View source for Silviculture

{{Short description|Practice of controlling forests for timber production}}

'''Silviculture''' is the practice of controlling the growth, composition/structure, as well as quality of [[forests]] to meet values and needs, specifically [[timber]] production.
The name comes from the Latin {{Lang|la|silvi-}} ('forest') and {{Lang|la|culture}} ('growing'). The study of forests and woods is termed ''[[silvology]]''. Silviculture also focuses on making sure that the treatment(s) of [[Stand level modelling|forest stands]] are used to conserve and improve their productivity.<ref name="Practice">{{cite book|title=The Practice of Silviculture|last1=Hawley|first1=Ralph C|last2=Smith|first2=David Martyn|publisher=Wiley|year=1954|edition=6th|location=New York|oclc=976898179}}</ref>

Generally, silviculture is the science and art of growing and cultivating forest crops based on a knowledge of silvics, the study of the life history and general characteristics of forest trees and stands, with reference to local/regional factors.<ref name="ford">{{cite book|title=Terminology of Forest Science, Technology Practice and Products: English-Language Version|last=International Union of Forestry Research Organizations|publisher=Society of American Foresters|others=F. C. Ford-Robertson|year=1971|isbn=978-0-939970-16-2|location=Washington, D.C.|oclc=223725063}}</ref> The focus of silviculture is the control, establishment and management of forest stands. The distinction between [[forestry]] and silviculture is that silviculture is applied at the [[Stand level modelling|stand-level]], while forestry is a broader concept. [[Adaptive management]] is common in silviculture, while forestry can include natural/conserved land without stand-level management and treatments being applied.

==Silvicultural systems==

The [[Forestry#History|origin of forestry]] in [[History of the forest in Central Europe|German-speaking Europe]] has defined silvicultural systems broadly as [[High forest (woodland)|high forest]] ({{Lang|de|Hochwald}}), [[Coppice|coppice with standards]] ({{Lang|de|Mittelwald}}) and compound coppice, [[short rotation coppice]], and [[coppice]] ({{Lang|de|Niederwald}}). There are other systems as well. These varied silvicultural systems include several harvesting methods, which are often wrongly said to be a silvicultural systems, but may also be called rejuvenating or regenerating method depending on the purpose.

The high forest system is further subdivided in German:<ref>Invented by Reiniger at The Schlägl Monastery, Austria http://www.stift-schlaegl.at/prodon.asp?peco=&Seite=373&Lg=1&Cy=1</ref> 
* High forest ({{Lang|de|Hochwald}})
** Age class forest ({{Lang|de|Altersklassenwald}})
*** Even-aged forestry
**** [[Clear cutting]] ({{Lang|de|Kahlschlag}})
**** [[Shelterwood cutting]] ({{Lang|de|Schirmschlag}})
**** [[Seed tree|Seed-tree method]]
*** Uneven-aged forestry
**** [[Selection cutting|The Femel selection cutting (group selection cutting)]] ({{Lang|de|Femelschlag}})
**** Strip selection cutting (strip-and-group [[felling]] system) ({{Lang|de|Saumschlag}})
**** Shelterwood wedge cutting ({{Lang|de|Schirmkeilschlag}})
**** Mixed-form regeneration methods ({{Lang|de|Mischformen}})
** [[Continuous cover forestry]] ({{Lang|de|Dauerwald}})
*** Uneven-aged forestry
**** [[Selection cutting|Selection forest]] ({{Lang|de|Plenterwald}})
**** Target diameter harvesting ({{Lang|de|Zielstärkennutzung}})
These names give the impression is that these are neatly defined systems, but in practice there are variations within these harvesting methods in accordance with to local ecology and site conditions. While location of an archetypal form of harvesting technique can be identified (they all originated somewhere with a particular forester, and have been described in the scientific literature), and broad generalizations can be made, these are merely rules of thumb rather than strict blueprints on how techniques might be applied.{{citation needed|date=January 2022}} This misunderstanding has meant that many older English textbooks did not capture the true complexity of silviculture as practiced where it originated in [[Mitteleuropa]].{{citation needed|date=January 2022}}

This silviculture was culturally predicated on wood production in [[Temperate climate|temperate]] and [[Subarctic climate|boreal climate]]s and did not deal with [[Dietrich Brandis|tropical forestry]]{{citation needed|date=January 2022}}. The misapplication of this philosophy to those tropical forests has been problematic{{according to whom?|date=January 2022}}. There is also an alternative silvicultural tradition which developed in [[Japan]] and thus created a different biocultural landscape called ''[[satoyama]]''.

After harvesting comes regeneration, which may be split into natural and artificial (see below), and tending, which includes release treatments, [[pruning]], [[thinning]] and intermediate treatments.<ref>{{cite book|title=Silviculture: Concepts and Applications|last=Nyland|first=Ralph D.|publisher=McGraw-Hill|year=2002|isbn=978-0-07-366190-2|edition=2nd|series=McGraw-Hill series in forest resources|location=Boston|pages=20}}</ref> It is conceivable that any of these three phases ([[Logging|harvesting]], [[Regeneration (ecology)|regeneration]], and tending) may happen at the same time within a stand, depending on the goal for that particular stand.

==Regeneration==
Regeneration is basic to the continuation of forested, as well as to the [[afforestation]] of treeless land. Regeneration can take place through self-sown [[seed]] ("natural regeneration"), by artificially sown seed, or by planted [[seedling]]s. In whichever case, the performance of regeneration depends on its growth potential and the degree to which its environment allows the potential to be expressed.<ref name="gross">{{cite book|title=Ecophysiology of Northern Spruce Species: The Performance of Planted Seedlings|last1=Grossnickle|first1=Steven C.|last2=National Research Council Canada|publisher=NRC Research Press|year=2000|isbn=978-0-660-17959-9}}</ref> Seed, of course, is needed for all regeneration modes, both for natural or artificial [[sowing]] and for raising planting stock in a [[Plant nursery|nursery]].

The process of natural regeneration involves the renewal of forests by means of self-sown seeds, root suckers, or coppicing. In natural forests, [[conifer]]s rely almost entirely on regeneration through seed. Most of the [[Forest#Classification|broadleaves]], however, are able to regenerate by the means of emergence of shoots from stumps (coppice) and broken stems.<ref>Huss J. (2004) Afforestation | Stand establishment, treatment and promotion – European experience; ''Encyclopedia of forest sciences''; Elsevier; pp. 14–27 https://doi.org/10.1016/B0-12-145160-7/00224-6</ref>{{Full citation needed|date=February 2018}}

===Seedbed requirements===

Any seed, self-sown or artificially applied, requires a seedbed suitable for securing [[germination]].

In order to [[germination|germinate]], a seed requires suitable conditions of temperature, [[Soil#Soil moisture|moisture]], and [[Pore space in soil|aeration]]. For seeds of many species, light is also necessary, and facilitates the germination of seeds in other species,<ref name="Schopmeyer 1974">{{cite book|url=https://archive.org/details/seedsofwoodyplan00fore|title=Seeds of Woody Plants in the United States|last=Schopmeyer|first=C. S.|publisher=United States Department of Agriculture Forest Service|year=1974|series=Agriculture Handbook No. 450|location=Washington, D.C.}}</ref> but spruces are not exacting in their light requirements, and will germinate without light. [[White spruce]] seed germinated at 35&nbsp;°F (1.7&nbsp;°C) and 40&nbsp;°F (4.4&nbsp;°C) after continuous stratification for one year or longer and developed [[radicle]]s less than {{Cvt|6|cm|}} long in the cold room.<ref name="MacArthur 1963">{{cite journal|last1=MacArthur|first1=JD|last2=Fraser|first2=JW|date=1963|title=Low temperature germination of some eastern Canadian tree seed|url=http://nofc.cfs.nrcan.gc.ca/bookstore_pdfs/30593.pdf|journal=Forestry Chronicle|volume=39|issue=4|pages=478–479|doi=10.5558/tfc39478-4|doi-access=free}}</ref> When exposed to light, those germinants developed [[chlorophyll]] and were normally [[Phototropism|phototropic]] with continued elongation.

For survival in the short and medium terms, a germinant needs: a continuing supply of moisture; freedom from lethal temperature; enough light to generate sufficient [[Photosynthate partitioning|photosynthate]] to support respiration and growth, but not enough to generate lethal stress in the seedling; freedom from [[Browsing (herbivory)|browsers]], tramplers, and [[pathogen]]s; and a stable root system. Shade is very important to the survival of young seedlings.<ref name="arn">{{cite book|title=Direct Seeding Symposium. Timmins, Ontario. September 11, 12, 13, 1973|last=Arnott|first=J. T.|publisher=Canadian Forestry Services|year=1974|editor-last=Cayford|editor-first=J.|location=Ottawa, ON|pages=55–66|chapter=Germination and seedling establishment|chapter-url=https://cfs.nrcan.gc.ca/publications?id=9272}}</ref><ref name=":0">{{cite book|title=Natural Regeneration of Engelmann Spruce After Clearcutting in the Central Rocky Mountains in Relation to Environmental Factors.|url=https://archive.org/details/CAT92273467|last=Alexander|first=R. R.|publisher=U.S. Dept. of Agriculture, Forest Service|year=1984|series=Research Paper RM|location=Fort Collins, Colorado|oclc=711671143}}</ref> In the longer term, there must be an adequate supply of essential nutrients and an absence of smothering.

In undisturbed forest, decayed [[windthrow|windfallen]] stemwood provides the most favorable seedbed for germination and survival. Seedlings growing on such sites are less likely to be buried by accumulated snowpack and leaf litter, and less likely to be subject to [[flood]]ing. Advantages conferred by those microsites include: more light, higher temperatures in the rooting zone, and better [[mycorrhiza]]l development.<ref name="Baldwin 1927">{{cite journal|last=Baldwin|first=Henry I.|date=1 July 1927|title=A Humus Study in Norway|journal=Ecology|volume=8|issue=3|pages=380–383|doi=10.2307/1929342|issn=1939-9170|jstor=1929342|bibcode=1927Ecol....8..380B }}</ref><ref name="mork">{{cite journal|last=Mork|first=Elias|date=1933|title=[Temperature as a factor of regeneration in the spruce forests of Northern Trondhjem]|journal=Meddelelser Fra Det Norske Skogforsøkvesen|volume=V|issue=16}} Reviewed in J. For. 32:1024, 1934.</ref><ref name="rowe">{{cite journal|last=Rowe|first=J. S.|date=1955|title=Factors influencing white spruce reproduction in Manitoba and Saskatchewan|url=http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/30470.pdf|journal=Canadian Forest Service Publications|volume=3}}</ref> According to a 1940 survey in the [[Porcupine Hills]] of [[Manitoba]], approximately 90% of spruce seedlings were germinating from this substrate.<ref name="rowe" /><ref name="phel2">{{cite journal|last=Phelps|first=V. H.|date=1940|title=Spruce regeneration in Canada: the Prairie Provinces.|journal=Forestry Chronicle|volume=16|pages=30–37}}</ref>

Mineral soil [[seedbed]]s are more receptive than the undisturbed forest floor,<ref name="alex2">{{cite journal|last1=Alexander|first1=R. R.|last2=Shepperd|first2=W. D.|date=1984|title=Silvical characteristics of Engelmann spruce.|url=https://www.fs.fed.us/rm/pubs_rm/rm_gtr114.pdf|journal=General Technical Report, Rocky Mountain Forest and Range Experiment Station, USDA Forest Service|issue= RM-114}}</ref> and are generally moister and more readily rewetted than the organic forest floor. However, exposed mineral soil, much more so than organic-surfaced soil, is subject to [[frost heaving]] and shrinkage during [[drought]]. The forces generated in soil by frost or drought are quite enough to break roots.<ref name="Sutton 1991">Sutton, R.F. 1991. Soil properties and root development in forest trees: a review. For. Can., Ont. Region, Sault Ste. Marie ON, Inf. Rep. O-X-413. 42 p.</ref>

The range of microsites occurring on the forest floor can be broadened, and their frequency and distribution influenced by site preparation. Each microsite has its own [[microclimate]]. Microclimates near the ground are better characterized by [[Vapour Pressure Deficit|vapour pressure deficit]] and net incident radiation, rather than the standard measurements of [[air temperature]], [[precipitation]], and wind pattern.<ref name=":0" />

[[Aspect (geography)|Aspect]] is an important component of microclimate, especially in relation to temperature and moisture regimes. Germination and seedling establishment of [[Picea engelmannii|Engelmann spruce]] were much better on north than on south aspect seedbeds in the [[Fraser Experimental Forest]], Colorado; the ratios of seeds to 5-year-old seedlings were determined as 32:1, 76:1, and 72:1 on north aspect bladed-shaded, bladed-unshaded, and undisturbed-shaded seedbeds, respectively.<ref name="alex3">{{cite book|url=https://books.google.com/books?id=96Mib4c5R7AC|title=Seed: Seedling Ratios of Engelmann Spruce After Clearcutting in the Central Rocky Mountains|last=Alexander|first=Robert R.|publisher=USDA Forest Service, Rocky Mountain Forest and Range Experiment Station|year=1983|series=Research Paper RM|location=Fort Collins, Colorado}}</ref> Clearcut openings of {{convert|1.2|to|2.0|ha}} adjacent to an adequate seed source, and not more than 6 tree-heights wide, could be expected to secure acceptable regeneration (4,900, 5-year-old trees per hectare), whereas on undisturbed-unshaded north aspects, and on all seedbed treatments tested on south aspects, seed to seedling ratios were so high that the restocking of any clearcut opening would be questionable.

At least seven variable factors may influence seed germination: seed characteristics, light, oxygen, soil reaction ([[pH]]), temperature, moisture, and seed enemies.<ref name="bald2">{{cite book|title=Forest Tree Seed of the North Temperate Regions With Special Reference to North America|last=Baldwin|first=Henry Ives|publisher=Chronica Botanica Co.|year=1942|edition=|location=Waltham MA}}</ref> Moisture and temperature are the most influential, and both are affected by exposure. The difficulty of securing natural regeneration of [[Norway spruce]] and [[Scots pine]] in northern Europe led to the adoption of various forms of reproduction cuttings that provided partial shade or protection to seedlings from hot sun and wind.<ref name="bald3">{{cite journal|last=Baldwin|first=Henry Ives|date=1 April 1933|title=The Density of Spruce and Fir Reproduction Related to the Direction of Exposure|journal=Ecology|volume=14|issue=2|pages=152–156|doi=10.2307/1932882|issn=1939-9170|jstor=1932882|bibcode=1933Ecol...14..152B }}</ref> The main objective of echeloned strips or border-cuttings with northeast exposure was to protect regeneration from overheating, and was originated in Germany and deployed successfully by A. Alarik in 1925 and others in Sweden.<ref name="alar">{{cite journal|last=Alarik|first=A.|date=1925|title=Moderna huggningsformer tillämpade pâ Finspång|journal=Skogen|language=sv|volume=12|pages=211–243}}</ref> On south and west exposures, direct insolation and heat reflected from tree trunks often result in temperatures lethal to young seedlings,<ref name="hart">{{cite journal|last=Hartley|first=Carl|date=1918|title=Stem lesions caused by excessive heat|url=https://naldc.nal.usda.gov/download/IND43966127/PDF|archive-url=https://web.archive.org/web/20180221100312/https://naldc.nal.usda.gov/download/IND43966127/PDF|url-status=dead|archive-date=February 21, 2018|journal=Journal of Agricultural Research|volume=14|issue=13|pages=595–604}}</ref> as well as desiccation of the surface soil, which inhibits germination. The sun is less injurious on eastern exposures because of the lower temperature in the early morning, related to higher [[humidity]] and presence of [[dew]].

In 1993, Henry Baldwin, after noting that summer temperatures in North America are often higher than those in places where border-cuttings have been found useful, reported the results of a survey of regeneration in a stand of [[red spruce]] plus scattered [[white spruce]] that had been isolated by clearcutting on all sides, so furnishing an opportunity for observing regeneration on different exposures in this old-field stand at [[Dummer, New Hampshire]].<ref name="bald3" /> The regeneration included a surprisingly large number of [[balsam fir]] seedlings from the 5% stand component of that species. The maximum density of spruce regeneration, determined 4 rods (20 m) inside from the edge of the stand on a north 20°E exposure, was 600,000/ha, with almost 100,000 balsam fir seedlings.

A prepared seedbed remains receptive for a relatively short period, seldom as long as 5 years, sometimes as short as 3 years. Seedbed receptivity on moist, fertile sites decreases with particular rapidity, and especially on such sites, seedbed preparation should be scheduled to take advantage of [[Mast (botany)#Mast seeding|good seed years]]. In poor seed years, site preparation can be carried out on mesic and drier sites with more chance of success, because of the generally longer receptivity of seedbeds there than those on moister sites.<ref name="eis">{{cite journal|last1=Eis|first1=S.|last2=Inkster|first2=J.|date=1 December 1972|title=White Spruce Cone Production and Prediction of Cone Crops|journal=Canadian Journal of Forest Research|volume=2|issue=4|pages=460–466|doi=10.1139/x72-070|bibcode=1972CaJFR...2..460E |issn=0045-5067}}</ref> Although an indifferent seed year can suffice if seed distribution is good and environmental conditions favourable to seedling germination and survival,<ref name="nob">{{cite book|url=https://archive.org/details/CAT92273418|title=Seedfall and Establishment of Engelmann Spruce and Subalpine Fir in Clearcut Openings in Colorado|last1=Noble|first1=Daniel L|last2=Ronco|first2=Frank|last3=Rocky Mountain Forest and Range Experiment Station (Fort Collins|first3=Colo.)|publisher=U.S. Dept. of Agriculture Forest Service|year=1978|series=Research Paper RM|location=Fort Collins, Colo.|oclc=6068388}}</ref> small amounts of seed are particularly vulnerable to depredation by small mammals.<ref name="rad">{{cite journal|last=Radvanyi|first=Andrew|date=1970|title=Small Mammals and Regeneration of White Spruce Forests in Western Alberta|journal=Ecology|volume=51|issue=6|pages=1102–1105|doi=10.2307/1933641|issn=0012-9658|jstor=1933641|bibcode=1970Ecol...51.1102R }}</ref> Considerable flexibility is possible in timing site preparation to coincide with cone crops. Treatment can be applied either before any logging takes place, between partial cuts, or after logging.<ref name="coat" /> In cut and leave strips, seedbed preparation can be carried out as a single operation, pre-scarifying the leave strips, post-scarifying the cut strips.<ref name="coat" />

[[Controlled burn|Broadcast burning]] is not recommended as a method of preparing sites for natural regeneration, as it rarely exposes enough mineral soil to be sufficiently receptive, and the charred organic surfaces are a poor seedbed for [[spruce]].<ref name="ack">{{cite journal|last=Ackerman|first=R. F.|date=1957|title=The effect of various seedbed treatments on the germination and survival of white spruce and lodgepole pine seedlings|url=http://www.cfs.nrcan.gc.ca/bookstore_pdfs/30541.pdf|journal=Forest Research Dvisiion Technical Note|issue=63}}</ref><ref name="zas2">{{cite book|title=Early Results of the Rosie Creek Fire Research Project, 1984|last=Zasada|first=J. C.|publisher=University of Alaska, Fairbanks Agricultural and Forestry Experiment Station|year=1985|editor-last=Juday|editor-first=Glenn|series=Miscellaneous Publications|volume=85-2|location=Fairbanks, Alaska|chapter=Production, dispersal and germination, and first-year seedling survival of white spruce and birch in the Rosie Creek burn|oclc=15124930|editor-last2=Dyrness|editor-first2=C.}}</ref><ref name="zas3">{{cite book|title=Forest Ecosystems in the Alaskan Taiga|last=Zasada|first=J.|publisher=Springer-Verlag|year=1986|isbn=978-1-4612-9353-8|editor-last=Cleve|editor-first=K.|series=Ecological Studies|location=New York|pages=44–73|chapter=Natural Regeneration of Trees and Tall Shrubs on Forest Sites in Interior Alaska|editor-last2=Chapin|editor-first2=F.|editor-last3=Flanagan|editor-first3=P.|editor-last4=Viereck|editor-first4=L.|editor-last5=Dyrness|editor-first5=C.}}</ref><ref name="zas4">{{cite journal|last1=Zasada|first1=John|last2=Norum|first2=Rodney|date=1 March 1986|title=Prescribed Burning White Spruce Slash in Interior Alaska|journal=Northern Journal of Applied Forestry|volume=3|issue=1|pages=16–18|doi=10.1093/njaf/3.1.16|issn=0742-6348}}</ref> A charred surface may get too hot for good germination and may delay germination until fall, with subsequent overwinter mortality of unhardened seedlings.<ref name="bell">Bell, F.W. 1991. Critical silvics of conifer crop species and selected competitive vegetation in northwestern Ontario. For. Can., Sault Ste. Marie, Ont./Ont. Min. Nat. Resour., Northwestern Ont. For. Tech. Devel. Unit, Thunder Bay ON, COFRDA Rep. 3310/ NWOFTDU Tech. Rep. 19. 177 p.</ref> Piling and burning of logging slash, however, can leave suitable exposures of mineral soil.<ref name="coat" />

===Season of planting===
{{See|Tree planting}}{{Empty section|date=February 2018}}

==Artificial regeneration==

With a view to reducing the time needed to produce planting stock, experiments were carried out with white spruce and three other [[Pinophyta|coniferous]] species from Wisconsin seed in the longer, frost-free growing season in [[Florida]], 125 vs. 265 days in central Wisconsin and northern Florida, respectively.<ref name="anon">Anon. 1961. Northern conifer planting stock produced under long [[Photoperiodism|photoperiods]] in Florida. p. 9–13 ''in'' 1960 Rep., Lake States For. Exp. Sta.</ref> As the species studied are adapted to long [[Photoperiodic|photoperiods]], extended [[daylength]]s of 20 hours were applied in Florida. Other seedlings were grown under extended daylength in Wisconsin and with natural daylength in both areas. After two growing seasons, white spruce under long days in Florida were about the same as those in Wisconsin, but twice as tall as plants under natural Wisconsin photoperiods. Under natural days in Florida, with the short local photoperiod, white spruce was severely dwarfed and had a low rate of survival. [[Picea mariana|Black spruce]] responded similarly. After two growing seasons, long day plants of all 4 species in Florida were well balanced, with good development of both roots and shoots, equaling or exceeding the minimum standards for 2+1 and 2+2 outplanting stock of Lake States species. Their survival when lifted in February and outplanted in Wisconsin equalled that of 2+2 Wisconsin-grown transplants. Artificial extension of the photoperiod in the northern Lake States greatly increased height increment of white and black spruces in the second growing season.

Optimum conditions for seedling growth have been determined for the production of containerized planting stock.<ref name="nien">{{Silvics |first1=Hans |last1=Nienstaedt |first2=John C. |last2=Zasada |volume=1 |genus=Picea |species=glauca}}</ref> Alternating day/night temperatures have been found more suitable than a constant temperature; at 400 lumens/m<sup>2</sup> light regime, a 28&nbsp;°C/20&nbsp;°C day/night temperatures have been recommended for white spruce.<ref name="nien" /><ref name="Pollard 1976">{{cite journal|last1=Pollard|first1=D. F. W.|last2=Logan|first2=K. T.|date=1976|title=Prescription for the aerial environment of a plastic greenhouse nursery|url=http://admin.rngr.net/publications/tree-improvement-proceedings/lake-states-forest-tree-improvement-conference-proceedings/1975/prescription-for-the-aerial-environment-of-a-plastic-greenhouse-nursery/at_download/file|journal=USDA Forest Service General Technical Report NC (USA)}}</ref> However, temperature optima are not necessarily the same at different ages and sizes.<ref name="nien" /> In 1984, R. Tinus investigated the effects of combinations of day and night temperature on height, caliper, and dry weight of 4 seed sources of Engelmann spruce. The 4 seed sources appeared to have very similar temperature requirements, with night optima about the same of slightly lower than daylight optima.<ref name="tin2">{{cite book|url=https://books.google.com/books?id=KDFK8b46EAwC&q=Optimum%20temperatures%20for%20growth%20of%20southern%20Rocky%20Mountain%20Engelmann%20spruce%20and%20Douglas-fir%20seedlings&pg=PP1|title=Optimum Temperatures for Growth of Southern Rocky Mountain Engelmann Spruce and Douglas-Fir Seedlings|last=Tinus|first=R. W.|publisher=USDA Forest Service, Rocky Mountain Forest and Range Experiment Station|year=1984|series=Research Paper RM|location=Fort Collins, Colorado}}</ref>

[[Provenance#Seed provenance|Tree provenance]] is important in artificial regeneration. Good provenance takes into account suitable tree genetics and a good environmental fit for planted / seeded trees in a forest stand. The wrong [[genotype]] can lead to failed regeneration, or poor trees that are prone to pathogens and undesired outcomes.

Artificial regeneration has been a more common method involving planting because it is more dependable than natural regeneration. Planting can involve using seedlings (from a nursery), (un)rooted cuttings, or seeds.<ref>{{cite book|title=Silviculture and Ecology of Western U.S. Forests|last1=Tappeiner|first1=John C.|last2=Maguire|first2=Douglas Alan|last3=Harrington|first3=Timothy Brian|publisher=Oregon State University Press|year=2007|isbn=978-0-87071-187-9}}</ref>

Whichever method is chosen it can be assisted by tending techniques also known as intermediate stand treatments.

The fundamental genetic consideration in artificial regeneration is that seed and planting stock must be adapted to the planting environment. Most commonly, the method of managing seed and stock deployment is through a system of defined seed zones, within which seed and stock can be moved without risk of climatic maladaptation.<ref name="joyce">{{cite book|title=Regenerating the Canadian Forest: Principles and Practice for Ontario|last1=Joyce|first1=D.|last2=Nitschke|first2=P.|last3=Mosseler|first3=A.|publisher=Fitzhenry & Whiteside|year=2001|isbn=978-1-55041-378-6|editor-last=Wagner|editor-first=R.G.|location=Markham, ON|pages=141–154|chapter=Genetic resource management|editor-last2=Colombo|editor-first2=S.}}</ref> Ontario adopted a seed zone system in the 1970s based on G.A. Hills' 1952<ref name="hills1">{{cite book|title=The Classification and Evaluation of Site for Forestry|last=Hills|first=G Angus|publisher=Ontario Department of Lands and Forests, Division of Research|year=1952}}</ref> site regions and provincial resource district boundaries, but Ontario's seed zones are now based on homogeneous climatic regions developed with the Ontario Climate Model.<ref name="Mackey 1996">{{cite journal|last1=MacKey|first1=Brendan G.|last2=McKenney|first2=Daniel W.|last3=Yang|first3=Yin-Qian|last4=McMahon|first4=June P.|last5=Hutchinson|first5=Michael F.|date=1 March 1996|title=Site regions revisited: a climatic analysis of Hills' site regions for the province of Ontario using a parametric method|journal=Canadian Journal of Forest Research|volume=26|issue=3|pages=333–354|doi=10.1139/x26-038|bibcode=1996CaJFR..26..333M |issn=0045-5067}}</ref><ref name="joyce" /> The regulations stipulate that source-identified seedlots may be either a general collection, when only the seed zone of origin is known, or a stand collection from a specific latitude and longitude. The movement of general-collection seed and stock across seed zone boundaries is prohibited, but the use of stand-collection seed and stock in another seed zone is acceptable when the Ontario Climate Model shows that the planting site and place of seed origin are climatically similar. The 12 seed zones for white spruce in Quebec are based mainly on ecological regions, with a few modifications for administrative convenience.<ref name="li">{{cite journal|last1=Li|first1=P|last2=Beaulieu|first2=J|last3=Bousquet|first3=J|date=1 February 1997|title=Genetic structure and patterns of genetic variation among populations in eastern white spruce (''Picea glauca'')|url=https://www.researchgate.net/publication/237870548|journal=Canadian Journal of Forest Research|volume=27|issue=2|pages=189–198|doi=10.1139/x96-159|bibcode=1997CaJFR..27..189L|issn=0045-5067}}</ref>

Seed quality varies with source. [[Seed orchard]]s produce seed of the highest quality, then, in order of decreasing seed quality produced, seed production areas and seed collection areas follow, with controlled general collections and uncontrolled general collections producing the least characterized seed.

===Seeds===

====Dewinging, extraction====

When seed is first separated from cones it is mixed with foreign matter, often 2 to 5 times the volume of the seed. The more or less firmly attached membranous wings on the seed must be detached before it is cleaned of foreign matter.<ref name="toum1">{{cite book|title=Seeding and Planting in the Practice of Forestry|last1=Toumey|first1=James W|last2=Korstian|first2=Clarence F|publisher=Wiley & Son|year=1954|location=New York|oclc=860730575 }}</ref> The testa must not incur damage during the dewinging process. Two methods have been used, dry and wet. Dry seed may be rubbed gently through a sieve that has a mesh through which only seed without wings can pass. Large quantities of seed can be processed in dewinging machines, which use cylinders of heavy wire mesh and rapidly revolving stiff brushes within to remove the wings. In the wet process, seed with wings attached are spread out 10&nbsp;cm to 15&nbsp;cm deep on a tight floor and slightly moistened throughout; light leather flails are used to free seed from the wings. B. Wang described a unique wet dewinging procedure in 1973 using a [[cement mixer]],<ref name="wang1">{{cite conference|last=Wang|first=Ben S.P.|date=1973|title=Collecting, processing and storing tree seed for research use|url=https://digitalcommons.usu.edu/aspen_bib/5279/|conference=IUFRO International Symposium on Seed Processing|location=Bergen, Norway|volume=1}}</ref> used at the Petawawa tree seed processing facility. Wings of white and [[Picea abies|Norway spruce]] seed can be removed by dampening the seed slightly before it is run through a [[Winnowing|fanning mill]] for the last time.<ref name="toum1" /> Any moistened seed must be dried before [[fermentation]] or [[Mold (fungus)|moulding]] sets in.

====Seed viability====

A [[Fluorescein diacetate hydrolysis|fluorescein diacetate (FDA)]] biochemical viability test for several species of [[Pinophyta|conifer seed]], including white spruce, estimates the proportion of live seed (viability) in a seedlot, and hence the percentage [[germination]] of a seedlot. The accuracy of predicting percentage germination was within +/- 5 for most seedlots.<ref name="nol" /> White spruce seed can be tested for viability by an indirect method, such as the fluorescein diacetate (FDA) test<ref name="nol">Noland, T.L.; Mohammed, G.H.; Seymour, N. 2001. Testing tree seed viability with FDA: what does it tell you? p. 23'' in'' Proc. Working together for our common future. LUSTR Co-op. Ann. Gen. Meet. & Workshop, Feb. 2001, Timmins ON.</ref> or ‘Ultra-sound';<ref name="coat" /> or by the direct growth method of ‘germination'. Samples of white spruce seed inspected in 1928 varied in viability from 50% to 100%, but averaged 93%.<ref name="toum">{{cite book|title=The Testing of Coniferous Tree Seeds at the School of Forestry, Yale University, 1906-1926|last1=Toumey|first1=James William|last2=Stevens|first2=Clark Leavitt|publisher=Yale University|year=1928|volume=21|oclc=3398562}}</ref> A 1915 inspection reported 97% viability for white spruce seed.<ref name="toum1" />

====Germinative testing====

The results of a germination test are commonly expressed as ''germinative capacity'' or a ''germination percentage'', which is the percentage of seeds that germinate during a period of time, ending when germination is practically complete. During extraction and processing, white spruce seeds gradually lost moisture, and total germination increased. Mittal et al. (1987)<ref name="mitt">Mittal, R.K.; Wang, B.S.P. 1987. Fungi associated with seeds of eastern white pine and white spruce during cone processing and seed extraction. Can. J. For. Res. 19(9):1026–1034.</ref> reported that white spruce seed from Algonquin Park, Ontario, obtained the maximum rate (94% in 6 days) and 99% total germination in 21 days after 14-week pre-chilling. The pre-treatment of 1% [[sodium hypochlorite]] increased germinability.

Encouraged by Russian success in using ultrasonic waves to improve the germinative energy and percentage germination of seeds of agricultural crops, Timonin (1966)<ref name="timon">Timonin, M.I. 1966. Effect of ultra-sound on the germination of white spruce and jack pine. Can. J. Bot. 44:113–115. (Cited in Coates et al. 1994).</ref> demonstrated benefits to white spruce germination after exposure of seeds to 1, 2, or 4 minutes of ultrasound generated by an [[MSE (centrifuges)|M.S.E.]] ultrasonic [[disintegrator]] with a power consumption of 280 VA and power impact of 1.35 amperes.<ref name="timon" />{{rp|Tables 3.18 and 3.19}} However, no seeds germinated after 6 minutes of exposure to ultrasound.

====Seed dormancy====

Seed [[dormancy]] is a complex phenomenon and is not always consistent within species.<ref name="Haddon 1982">Haddon, B.D.; Winston, D.A. 1982. Germination after two years storage of artificially ripened white spruce seed. p. 75–80 ''in'' Wang, B.S.P.; Pitel, J.A. (Eds.). Proc. Internat. Sympos. Forest Tree Seed Storage, Sept. 1980, Chalk River ON. Environ. Can., Can. For. Serv. (Cited in Coates et al. 1994).</ref> Cold stratification of white spruce seed to break dormancy has been specified as a requirement,<ref name="wang2">Wang, B.S.P. 1974a. Testing and treatment of Canadian white spruce seed to overcome dormancy. Assoc. Official Seed Analysts Proc. 64:72–79.</ref><ref name="zas">Zasada, J.C.; Foote, M.J.; Deneke, F.J.; Parkerson, R.H. 1978. Case history of an excellent white spruce cone and seed crop in interior Alaska: cone and seed production, germination and seedling survival. USDA, For. Serv., Pacific NW For. Range Exp. Sta., Portland OR, Gen. Tech. Rep. PNW-65. 53 p.</ref><ref name="arm7">Armson, K.A.; Sadreika, V. 1979. Forest tree nursery [[soil management]] and related practices – metric edition. Ont. Min. Nat. Resour., Div. For. For. Manage. Branch, Toronto ON. 179 p.</ref><ref name="simp2">Simpson, J.D.; Wang, B.S.P.; Daigle, B.I. 2004. Long-term storage of various Canadian hardwoods and conifers. Seed Sci. & Technol. 32:561–572.</ref> but Heit (1961)<ref name="heit2">Heit, C.E. 1961. Laboratory determination and recommended testing methods for 16 spruce (''Picea'') species. p. 165–171 ''in ''Assoc. Off. Seed Anal. 51st Annu. Meet. Proc. (Cited in Coates et al. 1994).</ref> and Hellum (1968)<ref name="hell">Hellum, A.K. 1968. A case against cold stratification of white spruce seed prior to nursery seeding. Can. Dep. For. and Rural Devel., For. Branch, Ottawa ON, Publ. 1243. 12 p.</ref> regarded stratification as unnecessary. Cone handling and storage conditions affect dormancy in that cold, humid storage (5&nbsp;°C, 75% to 95% relative humidity) of the cones prior to extraction seemingly eliminated dormancy by overcoming the need to stratify.<ref name="Haddon 1982" /> Periods of cold, damp weather during the period of cone storage might provide natural cold (stratification) treatment. Once dormancy was removed in cone storage, subsequent kiln-drying and seed storage did not reactivate dormancy.

Haddon and Winston (1982)<ref name="Haddon 1982" /> found a reduction in viability of stratified seeds after 2 years of storage and suggested that stress might have been caused by stratification, e.g., by changes in seed biochemistry, reduced embryo vigor, seed aging or actual damage to the embryo. They further questioned the quality of the 2-year-old seed even though high [[germination]] occurred in the samples that were not stratified.

====Cold stratification====

Cold stratification is the term applied to the storing of seeds in (and, strictly, in layers with) a moist medium, often peat or sand, with a view to maintaining viability and overcoming dormancy. Cold stratification is the term applied to storage at near-freezing temperatures, even if no medium is used. A common method of cold stratification, is to soak seed in tap water for up to 24 h, superficially dry it, then store moist for some weeks or even months at temperatures just above freezing.<ref name="van den Driessche 1969">van den Driessche, R. 1969. Forest nursery handbook. B.C. For. Serv., Victoria BC, Res. Notes 48. 44 p.</ref><ref name="san">Santon, J. 1970. Effect of stratification on germination of freshly harvested seed of several spruce and pine species in eastern Canada. Can. Dep. Fish. For., Can. For. Serv., Petawawa For. Exp. Sta., Chalk River ON, Inf. Rep. PS-X-17. 22 p.</ref><ref name="wang6">Wang, B.S.P. 1987. The beneficial effects of stratification on germination of tree seeds. p. 56–75 ''in'' Proc. Nurserymen's Meeting, Dryden ON, June 15–19, 1987. OMNR, Toronto ON.</ref> Although Hellum (1968)<ref name="hell"/> found that cold stratification of an Alberta seed source led to irregular germination, with decreasing germination with increasing length of the stratification period, Hocking's (1972)<ref name="hock">Hocking, D. 1972. Effects of stratification of Alberta white spruce and lodgepole pine seeds on emergence in operational seedbeds. Environ. Can., Can. For. Serv., Ottawa ON, Bi-mo. Res. Notes 28(4):26–27.</ref> paired test with stratified and nonstratified Alberta seed from several sources revealed no trends in response to stratification. Hocking suggested that seed maturity, handling, and storage needed to be controlled before the need for stratification could be determined. Later, Winston and Haddon (1981)<ref name="wins">Winston, D.A.; Haddon, B.D. 1981. Effects of early cone collection and artificial ripening on white spruce and red pine germination. Can. J. For. Res. 11:817–826.</ref> found that the storage of white spruce cones for 4 weeks at 5&nbsp;°C prior to extraction obviated the need for stratification.

====Seed ripeness====

Seed maturity cannot be predicted accurately from cone flotation, cone moisture content, cone specific gravity; but the province of B.C. found embryo occupying 90% + of the corrosion cavity and megagametophyte being firm and whitish in colour are the best predictors for white spruce in B.C.,<ref name="kolo">Kolotelo, D. 1997. Anatomy and morphology of conifer tree seed. Forest Nursery Technical Series 1.1 B.C. Min. for., 70 p.</ref> and Quebec can forecast seed maturity some weeks in advance by monitoring seed development in relation to heat-sums and the phenological progression of the inflorescence of fireweed (''Epilobium angustifolium'' L.), an associated plant species.<ref name="merc" /> Cone collection earlier than one week before seed maturity would reduce seed germination and viability during storage.<ref name="merc">Mercier, S. 1991. Maturation et indices de maturité des semences d'épinette blanche. [Maturation and maturity indexes of white spruce seeds.] Quebec Min. For., Quebec QC, Memoire Rech. For. 103. 62 p. [Fr.e.; E 4085]</ref> Four stages of maturation were determined by monitoring carbohydrates, polyols, organic acids, respiration, and metabolic activity. White spruce seeds require a 6-week post-harvest ripening period in the cones to obtain maximum germinability,<ref name="car2">Caron, G.E.; Wang, B.S.P.; Schooley, H.O. 1990. Effect of tree spacing, cone storage, and prechilling on germination of ''Picea glauca'' seed. For. Chron. 66(4):388–392.</ref> however, based on cumulative degree-days, seed from the same trees and stand showed 2-week cone storage was sufficient.<ref name="car3">Caron, G.E.; Wang, B.S.P.; Schooley, H.O. 1993. Variation in ''Picea glauca'' seed germination associated with the year of cone collection. Can. J. For. Res. 23(7):1306–1313.</ref>

==Forest tree nurseries==

See [[Plant nursery]]

==Forest tree plantations==

===Plantation establishment criteria===

Plantations may be considered successful when outplant performance satisfies certain criteria. The term "free growing" is applied in some jurisdictions. Ontario's "Free-to-Grow" (FTG) equivalent relates to a forest stand that meets a minimum stocking standard and height requirement, and is essentially free of competition from surrounding vegetation that might impede growth.<ref name="ont">Ontario Class Environmental Assessment for Timber Management. 1989. Ont. Min. Nat. Resour. Witness Statements, Evidence Panels I to XVII. Compiled 1989.02,22, Sections separately paginated.</ref> The FTG concept was introduced with the advent of the Forest Management Agreement program in Ontario in 1980 and became applicable to all management units in 1986. Policy, procedures, and methodologies readily applicable by forest unit managers to assess the effectiveness of regeneration programs were still under development during the Class Environmental Assessment hearings.

In British Columbia, the Forest Practices Code (1995)<ref name="forest">British Columbia. Ministry of Forests. 1995. Forest practices code of British Columbia: Silvicultural systems guidebook. BC MoF, BC Ministry of Environment, 44 p.</ref> governs performance criteria. To minimize the subjectivity of assessing [[deciduous]] competition as to whether or not a plantation is established, minimum specifications of number, health, height, and competition have been specified in British Columbia. However, minimum specifications are still subjectively set and may need to be fine-tuned in order to avoid unwarranted delay in according established status to a plantation. For example, a vigorous white spruce with a strong, multi-budded leading shoot and its crown fully exposed to light on 3 sides would not qualify as free-growing in the current British Columbia Code but would hardly warrant description as unestablished.

==Competition==

Competition arises when individual organisms are sufficiently close together to incur growth constraint through mutual modification of the local environment.<ref name="milt">Milthorpe, F.L. 1961. The nature and analysis of competition between plants of different species. p. 330–355'' in'' Mechanisms in Biological Competition. Sympos. Soc. Exp. Biol. 15, Cambridge Univ. Press, Cambridge, U.K.</ref> Plants may compete for light, moisture and nutrients, but seldom for space ''per se''. Vegetation management directs more of the site's resources into usable forest products, rather than just eliminating all competing plants.<ref name="buse1">Buse, L.J.; Baker, W.D. 1991. Determining necessity and priority for tending in young spruce plantations in northwestern Ontario. Ont. Min. Nat. Resour., Northwestern Ont. For. Technol. Devel. Unit, Thunder Bay ON, Tech. Note TN-08. 4 p.</ref> Ideally, site preparation ameliorates competition to levels that relieve the outplant of constraints severe enough to cause prolonged check.

The diversity of boreal and sub-boreal broadleaf-conifer mixed tree species stands, commonly referred to as the "mixedwoods", largely preclude the utility of generalizations and call for the development of management practices incorporating the greater inherent complexity of broadleaf-conifer mixtures, relative to single-species or mixed-species conifer forest.<ref name="simard">Simard, S. 1966.  1996. Mixtures of paper birch and conifers: An ecological balancing act. pp. 15-22 In: P.G. Comeau & K.D. Thomas (eds.) Silviculture of temperate boreal broadleaf-conifer mixtures. BC Ministry of Forests, Research Branch, Victoria, BC. Land Management Handbook 36.</ref> After harvesting or other disturbance, mixedwood stands commonly enter a prolonged period in which hardwoods overtop the coniferous component, subjecting them to intense competition in an understorey. It is well established that the regeneration and growth potential of understorey conifers in mixedwood stands is correlated to the density of competing hardwoods.<ref name="green">Green, D.S. 2004. Describing condition-specific determinants of competition in boreal and sub-boreal mixedwood stands. For. Chron. 80(6):736–742.</ref> To help apply "free-to-grow" regulations in British Columbia and Alberta, management guidelines based on distance-dependent relations within a limited radius of crop trees were developed, but Lieffers et al. (2002)<ref name="lie3">Lieffers, V.J.; Pinno, B.; Stadt, K.J. 2002. Light dynamics and free-to-grow standards in aspen-dominated mixedwood forests. For. Chron. 78(1):137–145.</ref> found that free-growing stocking standards did not adequately characterize light competition between broadleaf and [[Pinophyta|conifer]] components in boreal mixedwood stands, and further noted that adequate sampling using current approaches would be operationally prohibitive.

Many promising plantations have failed through lack of tending. Young crop trees are often ill-equipped to fight it out with competition resurgent following initial site preparation and planting.

Perhaps the most direct evaluation of the effect of competition on plantation establishment is provided by an effective [[herbicide]] treatment, given it is performed correctly and without contamination of waters of the state. The fact that herbicide treatment does not always produce positive results should not obscure the demonstrated potential of herbicides for significantly promoting plantation establishment. Factors that can vitiate the effectiveness of a herbicide treatment include: weather, especially temperature, prior to and during application; weather, especially wind, during application; weather, especially precipitation, in the 12 to 24 hours after application; vegetation characteristics, including species, size, shape, phenological stage, vigour, and distribution of weeds; crop characteristics, including species, phenology, and condition; the effects of other treatments, such as preliminary shearblading, burning or other prescribed or accidental site preparation; and the herbicide used, including dosage, formulation, carrier, spreader, and mode of application. There is a lot that can go wrong, but a herbicide treatment can be as good or better than any other method of site preparation.

===Competition indices===

The study of competition dynamics requires both a measure of the competition level and a measure of crop response. Various competition indices have been developed, e.g., by Bella (1971)<ref name="bella">Bella, I.E. 1971. A new competition model for individual trees. For. Sci. 17:364–372.</ref> and Hegyi (1974)<ref name="heg">Hegyi, F. 1974. A simulation model for managing jack pine stands. p. 74–90 ''in'' Fries, J. (Ed.). Growth Models for Tree and Stand Simulation. R. Coll. For., Dep. For. Yield Res., Res. Note 30.</ref> based on stem diameter, by Arney (1972),<ref name="arn2">Arney, J.D. 1972. Computer simulation of Douglas-fir tree and stand growth. Oregon State Univ., Corvallis OR, Ph.D. thesis. (Cited by Morris and MacDonald 1991, orig. not seen.)</ref> Ek and Monserud (1974),<ref name="ek">Ek, A.R.; Monserud, R.A. 1974. Trials with program FOREST: Growth and reproduction simulation of mixed species forest stands. p. 56–73 ''in'' Fries, J. (Ed.). Growth Models for Tree and Stand Simulation. R. Coll. For., Dep. For. Yield Res., Res. Note 30.</ref> and Howard and Newton (1984)<ref name="how2">Howard, K.M.; Newton, M. 1984. Overtopping by successional coast range vegetation slows Douglas-fir seedlings. J. For. 82:178–180.</ref> based on canopy development, and Daniels (1976),<ref name="dan">Daniels, R.F. 1976. Simple competition indices and their correlation with annual loblolly pine tree growth. For. Sci. 22:454–456.</ref> Wagner (1982),<ref name="wag">Wagner, R.G. 1982. A method for assessing severity of weeds in young plantations. ''in'' The Use of Herbicides in Forest Vegetation Management. Co-ordinated Research on Alternative Forestry Treatments and Systems (CRAFTS). Univ. Oregon, Dep. For. Sci., Portland OR. (Cited by Morris and MacDonald 1991, orig. not seen).</ref> and Weiner (1984)<ref name="wei">Weiner, J. 1984. Neighbourhood interference amongst ''Pinus rigida'' individuals. J. Ecol. 72:183–195.</ref> with proximity-based models. Studies generally considered tree response to competition in terms of absolute height or basal area, but Zedaker (1982)<ref name="zed">Zedaker, S.M. 1982. Growth and development of young Douglas-fir in relation to intra- and inter-specific competition. Oregon State Univ., Corvallis OR, Ph.D. thesis. (Cited by Morris and MacDonald 1991, orig. not seen.)</ref> and Brand (1986)<ref name="brand1">Brand, D.G.; Kehoe, P.; Connors, M. 1986. Coniferous afforestation leads to soil acidification in central Ontario. Can. J. For. Res. 16(6):1389–1391.</ref> sought to quantify crop tree size and environmental influences by using relative growth measures.

==Tending==

Tending is the term applied to pre-harvest silvicultural treatment of forest crop trees at any stage after initial planting or seeding. The treatment can be of the crop itself (e.g., spacing, pruning, thinning, and improvement cutting) or of competing vegetation (e.g., weeding, cleaning).<ref name="ford" />

===Planting===

How many trees per unit area (spacing) that should be planted is not an easily answered question. Establishment density targets or regeneration standards have commonly been based on traditional practice, with the implicit aim of getting the stand quickly to the free-to-grow stage.<ref name="AJW_WB_1995">Willcocks, A.[J.] and Bell, W. 1995. How initial [[forest plantation]] density affects future stand growth. OMNR, Northeast Science & Technology, NEST Tech. Note TN-008. 16 p.</ref> Money is wasted if more trees are planted than are needed to achieve desired stocking rates, and the chance to establish other plantations is proportionately diminished. Ingress (natural regeneration) on a site is difficult to predict and often becomes surprisingly evident only some years after planting has been carried out. Early stand development after harvesting or other disturbance undoubtedly varies greatly among sites, each of which has its own peculiar characteristics.

For all practical purposes, the total volume produced by a stand on a given site is constant and optimum for a wide range of density or stocking. It can be decreased, but not increased, by altering the amount of growing stock to levels outside this range.<ref name="Smith 1962">Smith, D.M. 1962. The Practice of Silviculture, 7th ed. Wiley & Sons, New York NY. 378 p.</ref> Initial density affects stand development in that close spacing leads to full site utilization more quickly than wider spacing.<ref name="omn">[OMNR] Ontario Ministry of Natural Resources. 1989. Operational guidelines for tree improvement in Ontario. Ont. Min. Nat. Resour., Toronto ON, 9 sections separately paginated.</ref> Economic operability can be advanced by wide spacing even if total production is less than in closely spaced stands.

Beyond the establishment stage, the relationship of average tree size and stand density is very important.<ref name="AJW_WB_1995"/> Various density-management diagrams conceptualizing the density-driven stand dynamics have been developed.<ref name="drew">Drew, J.T.; Flewelling, J.W. 1979. Stand density management: an alternative approach and its application to [[Douglas fir|Douglas-fir]] plantations. For. Sci. 25:518–532.</ref><ref name="arch">Archibald, D.J.; Bowling, C. 1995. Jack pine density management diagram for boreal Ontario. Ont. Min. Nat. Resour., Northeast Science & Technology, Tech. Note TN-005 NWST TN-31. 20 p.</ref> Smith and Brand's (1988)<ref name="Smith 1988">Smith, N.J.; Brand, D.G. 1988. Compatible growth models and stand density diagrams. p. 636–643 ''in'' Ek. A.R..; Shifley, S.R..; Burk, T.E. (Eds.). Forest Growth Modelling and Prediction. Vol. 2. Proc. IUFRO Conf., August 1987, Minneapolis MN.</ref> diagram has mean tree volume on the vertical axis and the number of trees/ha on the horizontal axis: a stand can either have many little trees or a few big ones. The self-thinning line shows the largest number of trees of a given size/ha that can be carried at any given time. However, Willcocks and Bell (1995)<ref name="AJW_WB_1995"/> caution against using such diagrams unless specific knowledge of the stand trajectory is known.

In the Lake States, plantations have been made with the spacing between trees varying from 3 by 3 to 10 by 10 feet (0.9 m by 0.9 m to 3.0 m by 3.0 m).<ref name="Kittredge">{{cite journal|last1=Kittredge|first1=J|title=Forest planting in the Lake States|journal=U.S.D.A., for. Serv., Washington DC, Agric. Bull.|date=1929|issue=1497|pages=87 p}}</ref> Kittredge recommended that no fewer than 600 established trees per acre (1483/ha) be present during the early life of a plantation. To insure this, at least 800 trees per acre (1077/ha) should be planted where 85% survival may be expected, and at least 1200/ac (2970/ha) if only half of them can be expected to live.<ref name="toum2">Toumey, J.W.; Korstian, C.F. 1954. Seeding and Planting in the Practice of Forestry., 3rd ed. Wiley & Son, New York NY. 520 p.</ref> This translates into recommended spacings of 5 by 5 to 8 by 8 feet (1.5 m by 1.5 m to 2.4 m by 2.4 m) for plantings of conifers, including white spruce in the Lake States.

===Enrichment planting===
{{main|Enrichment planting}}
A strategy for enhancing natural forests' economic value is to increase their concentration of economically important, indigenous tree species by planting seeds or seedlings for future harvest, which can be accomplished with [[enrichment planting]] (EP).<ref>5 Keefe, K. 2012;</ref><ref>[http://www.grida.no/climate/ipcc/land_use/235.htm 'Fact Sheet 4.12. Forest Regeneration', ''IPCC Special Report on Land Use, Land-Use Change And Forestry'']</ref>

===Release treatments===
* [[Weed control|Weeding]]: A process of getting rid of saplings' or seedlings' competition by mowing, application of herbicide, or other method of removal from the surroundings.<ref>Daniel, Theodore, John Helms, and Frederick Baker. ''Principles of Silviculture''. 2nd ed. New York: McGraw-Hill, 1979. Print.</ref>
* [[Cleaning (forestry)|Cleaning]]: Release of select saplings from competition by overtopping trees of a comparable age.  The treatment favors trees of a desired species and stem quality.
* [[Liberation cutting]]: A treatment that releases tree seedling or saplings by removing older overtopping trees.

===Spacing===

Over-crowded regeneration tends to stagnate. The problem is aggravated in species that have little self-pruning ability, such as [[Picea glauca|white spruce]]. Spacing is a thinning (of natural regeneration), in which all trees other than those selected for retention at fixed intervals are cut. The term juvenile spacing is used when most or all of the cut trees are unmerchantable.<ref name="llo">Lloyd, G.D. 1991. Juvenile spacing in rgw sub-boreal spruce biogeoclimatic region of British Columbia. p. 20–26 ''in'' Haavisto, V.F.; Smith, C.R.; Mason, C. (Eds.). Space to grow: spacing and thinning in northern Ontario. Proc. sympos., June 1990, Sault Ste. Marie ON, For. Can., Ont. Region/Ont. Min. Nat. Resour. Joint Rep. 15.</ref> Spacing can be used to obtain any of a wide range of forest management objectives, but it is especially undertaken to reduce density and control [[stocking]] in young stands and prevent stagnation, and to shorten the rotation, i.e., to speed the production of trees of a given size. Volume growth of individual trees and the merchantable growth of stands are increased.<ref name="herm">Hermelin, J. 1991. Spacing in eastern Canada: the New Brunswick experience. p. 27–29 ''in'' Haavisto, V.F., Smith, C.R.; Mason, C. (Eds.). Space to grow: spacing and thinning in northern Ontario. Proc. Sympos., June 1990, Sault Ste. Marie ON, For. Can., Ont. Region/Ont. Min. Nat. Resour. Joint Rep. 15.</ref> The primary rationale for spacing is that thinning is the projected decline in maximum allowable cut.<ref name="nic">Nicks. B.D. 1991. A company perspective on spacing and thinning. p. 62–67 ''in'' Haavisto, V.F.; Smith, C.R.; Mason, C. (Eds.). Space to grow: spacing and thinning in northern Ontario. Proc. sympos., June 1990, Sault Ste. Marie ON, For. Can., Ont. Region/Ont. Min. Nat. Resour. Joint Rep. 15.</ref> And since wood will be concentrated on fewer, larger, and more uniform stems, operating and milling costs will be minimized.

Methods for spacing may be: manual, using various tools, including power saws, brush saws, and clippers; mechanical, using choppersand mulchers; chemical; or combinations of several methods. One treatment has had notable success in spacing massively overstocked (<100 000 stems/ha) natural regeneration of spruce and fir in Maine. Fitted to helicopter, the Thru-Valve boom emits herbicide spray droplets 1000&nbsp;μm to 2000&nbsp;μm in diameter<ref name="MacKay 1991">MacKay, T. 1991. Reducing stem density with herbicides: what are the options?. p. 99–103 ''in'' Haavisto, V.F.; Smith, C.R.; Mason, C. (Eds.). Space to grow: spacing and thinning in northern Ontario. Proc. sympos., June 1990, Sault Ste. Marie ON, For. Can., Ont. Region/Ont. Min. Nat. Resour. Joint Rep. 15.</ref> at very low pressure. Swaths 1.2 m wide and leave strips 2.4 m wide were obtained with "knife-edge" precision when the herbicide was applied by helicopter flying at a height of 21 m at a speed of 40–48&nbsp;km/h. It seems likely that no other method could be as cost-effective.

Twenty years after spacing to 2.5 × 2.5 m, 30-year-old mixed stands of [[Abies balsamea|balsam fir]] and white spruce in the Green River watershed, New Brunswick, averaged 156.9 m<sup>3</sup>/ha.<ref name="ker">Ker, M.F. 1981. Early response of balsam fir to spacing in northwestern New Brunswick. Environment Canada, Canadian Forestry Service, Maritimes Forestry Centre, Fredericton, New Brunswick, Information Report M-X-129, 36 p.</ref>

A spacing study of 3 conifers (white spruce, [[red pine]] and [[jack pine]]) was established at Moodie, Manitoba, on flat, sandy, nutritionally poor soils with a fresh moisture regime.<ref name="bell1">Bella, I.E. 1986. Spacing effects 20 years after planting three conifers in Manitoba. Can., Can. For. Serv., Edmonton AB, For. Manage. Note No. 39. 11 p.</ref> Twenty years after planting, red pine had the largest average dbh, 15% greater than [[jack pine]], while white spruce dbh was less than half that of the pines. Crown width showed a gradual increase with spacing for all 3 conifers. Results to date were suggesting optimum spacings between 1.8 m and 2.4 m for both pines; white spruce was not recommended for planting on such sites.

Comparable data are generated by espacement trials, in which trees are planted at a range of densities. Spacings of 1.25 m, 1.50 m, 1.75 m, 2.00 m, 2.50 m, and 3.00 m on 4 site classes were used in the 1922 trial at Petawawa, Ontario. In the first of 34 old field white spruce plantations used to investigate stand development in relation to spacing at Petawawa, Ontario, regular rows were planted at average spacings of from 4 × 4 to 7 × 7 feet (1.22 m × 1.22 m to 2.13 m × 2.13 m).<ref name="stie">Stiell, W.M.; Berry, A.B. 1973. Development of unthinned white spruce plantations to age 50 at Petawawa Forest Experiment Station. Can. Dep. Environ., Can. For. Serv., Ottawa ON, Publ. 1317. 18 p.</ref> Spacings up to 10 × 10 feet (3.05 m × 3.03 m) were subsequently included in the study. Yield tables based on 50 years of data showed:

* Except for merchantable volumes at age 20 and site classes 50 and 60, closer spacings gave greater standing volumes at all ages than did wider spacings, the relative difference decreasing with age.
* Merchantable volume as a proportion of total volume increases with age, and is greater at wider than at closer spacings.
* Current annual volume increment culminates sooner at closer than at wider spacings.

A smaller espacement trial, begun in 1951 near Thunder Bay, Ontario, included white spruce at spacings of 1.8 m, 2.7 m, and 3.6 m.<ref name="ont2">[OMNR] Ontario Ministry of Natural Resources. 1989. Forest management research area Thunder Bay spacing trial. OMNR, Toronto ON, Queen's Printer. 9 p.</ref> At the closest spacing, mortality had begun at 37 years, but not at the wider spacings.

The oldest interior spruce espacement trial in British Columbia was established in 1959 near Houston in the Prince Rupert Forest Region.<ref name="Pollack 1992">Pollack, J.C.; Johnstone, W.; Coates, K.D.; LePage, P. 1992. The influence of initial espacement on the growth of a 32-year-old white spruce plantation. B.C. Min. For., Victoria BC, Res. Note 111. 16 p.</ref> Spacings of 1.2 m, 2.7 m, 3.7 m, and 4.9 m were used, and trees were measured 6, 12, 16, 26, and 30 years after planting. At wide espacements, trees developed larger diameters, crowns, and branches, but (at 30 years) basal area and total volume/ha were greatest in the closest espacement (Table 6.38). In more recent trials in the Prince George Region of British Columbia (Table 6.39) and in Manitoba,<ref name="bell2">Bella, I.E.; De Franceschi, J.P. 1980. Spacing effects 15 years after planting three conifers in Manitoba. Can. Dep. Environ., Can. For. Serv., Northern For. Res. Centre, Edmonton AB, Inf. Rep. NOR-X-223. 10 p.</ref> planting density of white spruce had no effect on growth after up to 16 growing seasons, even at spacings as low as 1.2 m. The slowness of juvenile growth and of crown closure delay the response to intra-competition. Initially, close spacing might even provide a positive nurse effect to offset any negative response to competition.

===Thinning===
{{further|Thinning#In forestry}}

Thinning is an operation that artificially reduces the number of trees growing in a stand with the aim of hastening the development of the remainder.<ref>6 Savill, P.S. 2004;</ref> The goal of [[thinning]] is to control the amount and distribution of available growing space. By altering [[Stocking (forestry)|stand density]], [[foresters]] can influence the growth, quality, and health of residual [[trees]]. It also provides an opportunity to capture mortality and cull the commercially less desirable, usually smaller and malformed, trees. Unlike regeneration treatments, thinnings are not intended to establish a new tree crop or create permanent canopy openings.

Thinning greatly influences the [[ecology]] and micro-meteorology of the stand, lowering the inter-tree competition for water. The removal of any tree from a stand has repercussions on the remaining trees both above-ground and below. Silvicultural thinning is a powerful tool that can be used to influence stand development, stand stability, and the characteristics of the harvestable products.

Tending and thinning regimes and wind and snow damage are intimately related when considering intensive [[Pinophyta|conifer]] plantations designed for maximum production.<ref name="nav">Navratil, S.; Branter, K.; and Zasada, J. 1991. Regeneration in the mixedwoods. p. 32–48 ''in'' Shortreid, A. (Ed.), Proc. Northern Mixedwood ‘89: a symposium at Fort St. John, B.C., Sept. 1989. For. Can., Pacific For. Centre, Victoria BC, FRDA Report 164.</ref>

Previous studies have demonstrated that repeated thinnings over the course of a forest rotation increase carbon stores relative to stands that are clear-cut on short rotations and that the carbon benefits differ according to thinning method (e.g., thinning from above versus below).<ref>7 D'Amato, Anthony W. 2011;</ref>

====Precommercial thinning====
In the early development of forest stand, density of trees remain high and there is competition among trees for nutrients. When natural regeneration or artificial seeding has resulted in dense, overstocked young stands, natural [[thinning]] will in most cases eventually reduce stocking to more silviculturally desirable levels. But by the time some trees reach merchantable size, others will be overmature and defective, and others will still be unmerchantable. To reduce this unbalance and to obtain more economic returns, in the early stage, one kind of cleaning is done which is known as precommercial thinning. Generally, one or two times precommercial thinning is done to facilitate the growth of the tree
The yield of merchantable wood can be greatly increased and the rotation shortened by precommercial thinning.<ref name="Day 1967">Day, M.W. 1967. Pre-commercial thinning in conifers with silvicides. Michigan State Univ., Agric. Exp. Sta., East Lansing MI, Quarterly Bull 50:59–62.</ref> Mechanical and chemical methods have been applied, but their costliness has militated against their ready adoption.

===Pruning===
[[Pruning]], as a silvicultural practice, refers to the removal of the lower branches of the young trees (also giving the shape to the tree) so clear [[Wood#Knots|knot]]-free wood can subsequently grow over the branch stubs. Clear knot-free [[lumber]] has a higher value. Pruning has been extensively carried out in the [[Monterey pine|Radiata pine]] plantations of [[New Zealand]] and [[Chile]]; however, the development of [[finger joint]] technology in the production of [[lumber]] and [[molding (decorative)|mouldings]] has led to many forestry companies reconsidering their pruning practices. ''Brashing'' is an alternative name for the same process.<ref>[http://dictionaryofforestry.org/dict/term/brashing The Dictionary of Forestry, The Society of American Foresters]</ref>
Pruning can be done to all trees, or more cost effectively to a limited number of trees. There are two types of pruning: natural or self-pruning and artificial pruning. Most cases of self-pruning happen when branches do not receive enough sunlight and die. Wind can also take part in natural pruning which can break branches.<ref>Smith, D.M., B.C. Larson, M.J. Kelty, and P.M.S. Ashton. ''The Practice of Silviculture: Applied Forest Ecology.'' 9th edition. New York: John Wiley & Sons, Inc., 1997. Print.</ref> Artificial pruning is where people are paid to come and cut the branches. Or it can be natural, where trees are planted close enough that the effect is to cause self-pruning of low branches as energy is put into growing up for light reasons and not branchiness.

===Stand Conversion===

The term ''stand conversion'' refers to a change from one silvicultural system to another and includes ''species conversion'', i.e., a change from one species (or set of species) to another.<ref name="ford" /> Such change can be effected intentionally by various silvicultural means, or incidentally by default e.g., when high-grading has removed the [[Pinophyta|coniferous]] content from a [[mixedwood stand]], which then becomes exclusively self-perpetuating [[aspen]]. In general, such sites as these are the most likely to be considered for conversion.

==Growth and yield==

In discussing yields that might be expected from the Canadian [[spruce]] forests, Haddock (1961)<ref name="Haddock 1961">Haddock, P.G. 1961. Silvicultural views on the Canadian spruce forests. For. Chron. 37(4):376–389.</ref> noted that Wright's (1959)<ref name="wri">Wright, T.G. 1959. The Canadian spruce forest. For. Chron. 35(4):291–297.</ref> quotation of spruce yields in the British Isles of 220 cubic feet per acre (15.4 m<sup>3</sup>/ha) per year and in Germany of 175 cubic feet per acre (12.25 m<sup>3</sup>/ha) per year was misleading, at least if it was meant to imply that such yields might be approached in the [[Taiga|Boreal Forest]] Region of Canada. Haddock thought that Wright's suggestion of 20 to 40 (average 30) cubic feet per acre (1.4 m<sup>3</sup>/ha to 2.8 m<sup>3</sup>/ha (average 2.1 m<sup>3</sup>/ha) per year was more reasonable, but still somewhat optimistic.

The principal way forest resource managers influence growth and yield is to manipulate the mixture of species and number (density) and distribution (stocking) of individuals that form the [[Canopy (biology)|canopy]] of the stand.<ref name="dav">Davis, L.S.; Johnson, K.N. 1987. Forest Management, 3rd ed. McGraw-Hill, New York, NY. 790 p.</ref><ref name="burg">Burgess, D.; Larocque, G.R.; Brand, D.G. 2001. Forest growth and future yields: the importance of today's regeneration practices. P. 603–624 ''in'' Wagner, R.G.; Colombo, S.J. (Eds.). Regenerating the Canadian Forest: Principles and Practice for Ontario. Fitzhenry & Whiteside, Markham ON in co-operation with Ont. Min. Nat. Resour. 650 p.</ref> [[Species composition]] of much of the [[Taiga|boreal]] forest in North America already differs greatly from its pre-exploitation state. There is less [[spruce]] and more [[hardwood]]s in the second-growth forest than in the original forest; Hearnden et al. (1996)<ref name="hear">Hearnden, K.W.; Millson, S.V.; Wilson, W.C. 1996. Ontario Independent Forest Audit Committee. Ont. Min. Nat. Resour., Sault Ste. Marie ON. 117 p.</ref> calculated that the spruce cover type had declined from 18% to only 4% of the total forested area in Ontario. Mixedwood occupies a greater proportion of Ontario's second-growth forest (41%) than in the original (36%), but its component of white spruce is certainly much diminished.

Growth performance is certainly influenced by site conditions and thus by the kind and degree of site preparation in relation to the nature of the site. It is important to avoid the assumption that site preparation of a particular designation will have a particular silvicultural outcome. Scarification, for instance, not only covers a wide range of operations that scarify, but also any given way of scarifying can have significantly different results depending on site conditions at the time of treatment. In point of fact, the term is commonly misapplied. ''Scarification'' is defined<ref name="ford" /> as "loosening the top soil of open areas, or breaking up the forest floor, in preparation for regenerating by direct seeding or natural seedfall", but the term is often misapplied to practices that include scalping, screefing, and blading, which pare off low and surface vegetation, together with most off its roots to expose a weed-free surface, generally in preparation for sowing or planting thereon.

Thus, it is not surprising that literature can be used to support the view that the growth of seedlings on scarified sites is much superior to that of growth on similar sites that have not been scarified,<ref name="wald4">Waldron, R.M. 1966. Factors affecting natural white spruce regeneration on prepared seedbeds at the Riding Mountain Forest Experimental Area, Manitoba. Can. Dep. For. Rural Devel., For. Branch, Ottawa ON, Deptl. Publ. 1169. 41 p.</ref><ref name="butt1">Butt, G.; Bancroft, B.; Folk, R. 1989. Ingress of Engelmann spruce and subalpine fir in southern interior ESSF. For. Can./B.C. Min. For., Victoria BC, Project 3.61, unpub. rep. (Cited in Coates et al. 1994)</ref><ref name="you">Youngblood, A.P.; Zasada, J.C. 1991. White spruce artificial regeneration options on river floodplains in interior Alaska. Can. J. For. Res. 21(4):423–433.</ref> while other evidence supports the contrary view that scarification can reduce growth.<ref name="Day 1970" /><ref name="herr">Herring, L.J.; McMinn, R.G. 1980. Natural and advanced regeneration of Engelmann spruce and subalpine fir compared 21 years after site treatment. For. Chron. 56:55–57.</ref><ref name="mcm">McMinn, R.G. 1986. Comparative productivity of seedbed, natural and planted regeneration following various site treatments in white spruce clearcuts. p. 31–33'' in'' Murray, M. (Ed.), The Yield Advantages of Artificial Regeneration at High Latitudes. Proc. 6th Internat. Workshop on Forest Regeneration. USDA, For. Serv., Pacific Northwest For. Range Exp. Sta., Gen. Tech. Rep. PNW-194. 60 p. (Cited in Coates et al. 1994).</ref> Detrimental results can be expected from scarification that impoverishes the rooting zone or exacerbates edaphic or climatic constraints.

Burning site preparation has enhanced spruce seedling growth,<ref name="butt1" /> but it must be supposed that burning could be detrimental if the nutrient capital is significantly depleted. An obvious factor greatly influencing regeneration is competition from other vegetation. In a pure stand of [[Picea abies|Norway spruce]], for instance, Roussel (1948)<ref name="rous">Roussel, L. 1948. Couvert et photométrie. Bull. Soc. Forest Franche-Comté 25:313–326. For. Abs. 10:458–459, 1949.</ref> found the following relationships:

{| align="center" border="1" width=60%
| '''Percent cover (%)'''
| '''Vegetation Description'''
|- 
| Below 1 
| No vegetation
|-
| 1-3 
| Moss carpet with a few fir seedlings
|- 
| 4-10 
| Herbaceous plants appear
|-
| 10-25 
| Bramble, herbs, fairly vigorous spruce seedlings
|- 
| >25 
| Herbs, brambles very dense, vigorous, no moss
|}

A factor of some importance in solar radiation–reproduction relationships is excess heating of the soil surface by radiation.<ref name="reif">Reifsnyder, W.E.; Lull, H.W. 1965. Radiant Energy in Relation to Forests. USDA, For. Serv. Washington DC, Tech. Bull. 1344. 111 p.</ref> This is especially important for seedlings, such as [[spruce]], whose first leaves do not shade the base of the stem at the soil surface. Surface temperatures in sandy soils on occasion reach lethal temperatures of 50&nbsp;°C to 60&nbsp;°C.

==Common methods of harvesting==
Silvicultural regeneration methods combine both the harvest of the timber on the stand and re-establishment of the forest. The proper practice of sustainable forestry<ref>[http://oregonfuture.oregonstate.edu/part1/pf1_02.html Oregon State University Extension Service]</ref> should mitigate the potential negative impacts, but all harvest methods will have some impacts on the land and residual stand.<ref>[http://www.cnrhome.uidaho.edu/default.aspx?pid=73972 RESIDUAL DAMAGE IN A CONIFER STAND THINNED WITH A CTL SYSTEM, University of Idaho]</ref> The practice of sustainable forestry limits the impacts such that the values of the forest are maintained in perpetuity. Silvicultural prescriptions are specific solutions to a specific set of circumstances and management objectives.<ref>8 Bauhus, Jürgen 2009;</ref>  Following are some common methods:

===Clearcut harvesting===
Conventional clearcut harvesting is relatively simple: all trees on a cutblock are felled and bunched with bunches aligned to the skidding direction, and a skidder then drags the bunches to the closest log deck.<ref name="saud">Sauder, E.A. 1996. Techniques to maintain a windfirm understory. p. 31 ''in'' FERIC West, Vancouver BC, Work Program 1996.</ref> Feller-buncher operators concentrate on the width of the felled swath, the number of trees in a bunch, and the alignment of the bunch. Providing a perimeter boundary is felled during daylight, night-shift operations can continue without the danger of trespassing beyond the block. Productivity of equipment is maximized because units can work independently of one another.

===[[Clearcutting]]===
An [[Even-aged timber management|even-aged regeneration method]] that can employ either natural or [[Treeplanting|artificial]] regeneration. It involves the complete removal of the forest stand at one time.<ref>''Effects of Group-Selection Opening Size on Breeding Bird Habitat Use in a Bottomland Forest.'' Christopher E. Moorman and David C. Guynn Jr.
 Ecological Applications, Vol. 11, No. 6 (Dec., 2001), pp. 1680-1691. Web. 4 Oct. 2013.</ref>  Clearcutting can be biologically appropriate with species that typically regenerate from stand replacing fires or other major [[Disturbance (ecology)|disturbances]], such as [[Lodgepole Pine]] (''Pinus contorta''). Alternatively, clearcutting can change the dominating species on a stand with the introduction of non-native and invasive species as was shown at the Blodgett Forest Research Station near [[Georgetown, California]]. Additionally, clearcutting can prolong [[Slash (logging)|slash]] decomposition, expose soil to erosion, impact visual appeal of a landscape and remove essential wildlife habitat. It is particularly useful in regeneration of tree species such as [[Douglas-fir]] (''Pseudotsuga menziesii'') which is [[List of shade-tolerant species|shade intolerant]].{{Verify source|date=April 2012}}.  In addition, the general public's distaste for even-aged silviculture, particularly clearcutting, is likely to result in a greater role for uneven-aged management on public lands as well.<ref>9 Schulte, Benedict J. 1998;</ref> Across Europe, and in parts of North America, even-aged, production-orientated and intensively managed plantations are beginning to be regarded in the same way as old industrial complexes: something to abolish or convert to something else.<ref>12 Gamborg, Christian 2003;</ref>

Clearcutting will impact many site factors important in their effect on regeneration, including air and [[soil]] temperatures. Kubin and Kemppainen (1991),<ref name="kubin">Kubin, E.; Kemppainen, L. 1991. Effect of clearcutting of boreal spruce forest on air and soil temperature conditions. Acta Forestalia Fennica No. 225. 42 p.</ref> for instance, measured temperatures in northern Finland from 1974 through 1985 in three clear-felled areas and in three neighbouring forest stands dominated by [[Picea abies|Norway spruce]]. Clear felling had no significant influence on air temperature at 2 m above the ground surface, but the daily air temperature maxima at 10&nbsp;cm were greater in the clear-felled area than in the uncut forest, while the daily minima at 10&nbsp;cm were lower. Night frosts were more common in the clear-felled area. Daily soil temperatures at 5&nbsp;cm depth were 2&nbsp;°C to 3&nbsp;°C greater in the clear-felled area than in the uncut forest, and temperatures at depths of 50&nbsp;cm and 100&nbsp;cm were 3&nbsp;°C to 5&nbsp;°C greater. The differences between the clear-felled and uncut areas did not diminish during the 12 years following cutting.

===[[Coppicing]]===
A regeneration method which depends on the sprouting of cut trees.  Most hardwoods, the [[coast redwood#Reproduction|coast redwood]], and certain pines naturally sprout from stumps and can be managed through coppicing. Coppicing is generally used to produce fuelwood, pulpwood, and other products dependent on small trees. A close relative of coppicing is [[pollarding]].<ref>Smith, D.M., B.C. Larson, M.J. Kelty, P.M.S. Ashton (1997) The Practice of Silviculture: Applied Forest Ecology, John Wiley & Sons, p. 340-46</ref> Three systems of coppice woodland management are generally recognized: simple coppice, coppice with standards, and the coppice selection system.<ref>10 Harmer, R. 2004;</ref>
*In Compound coppicing or '''coppicing with standards''', some of the highest quality trees are retained for multiple rotations in order to obtain larger trees for different purposes.

===Direct seeding===
Prochnau (1963),<ref name="proch">Prochnau, A.E. 1963. Direct seeding experiments with white spruce, alpine fir, Douglas fir and lodgepole pine in the central interior of British Columbia. B.C. Min. For. Lands, Victoria BC, MOFL No. 37, Res Note. 24 p. (Cited in Coates et al. 1994).</ref> four years after sowing, found that 14% of viable white spruce seed sown on mineral [[soil]] had produced surviving seedlings, at a seed:seedling ratio of 7.1:1.  With Engelmann spruce, Smith and Clark (1960)<ref name="Smith 1960">Smith, J.H.G.; Clark, M.B. 1960. Growth and survival of Engelmann spruce and alpine fir on seed spots at Bolean Lake, B.V. 1954–59. For. Chron. 36(1):46–49, 51. (Cited in Coates et al. 1994).</ref> obtained average seventh year seed:seedling ratios of 21:1 on scarified seedbeds on dry sites, 38:1 on moist sites, and 111:1 on litter seedbeds.

===[[Selection cutting#Group selection|Group selection]]===
The group selection method is an uneven-aged regeneration method that can be used when mid-tolerant species regeneration is desired.  The group selection method can still result in residual stand damage in dense stands, however directional falling can minimize the damage.  Additionally, [[forester]]s can select across the range of diameter classes in the stand and maintain a mosaic of age and diameter classes.

==={{Lang|fr|Méthode du contrôle}}===
Classical European silviculture achieved impressive results with systems such as Henri Biolley's {{Lang|fr|méthode du contrôle}} in Switzerland, in which the number and size of trees harvested were determined by reference to data collected from every tree in every stand measured every seven years.<ref name="bio">Biolley, H. 1920. L'aménagement des forêts par la méthode expérimentale et spécialement la méthode du contrôle. Paris, Attinger frères. 90 p.</ref>

While not designed to be applied to boreal mixedwoods, the {{Lang|fr|méthode du contrôle}} is described briefly here to illustrate the degree of sophistication applied by some European foresters to the management of their forests. Development of management techniques that allowed for stand development to be monitored and guided into sustainable paths were in part a response to past experience, particularly in Central European countries, of the negative effects of pure, uniform stands with species often unsuited to the site, which greatly increased the risk of [[soil retrogression and degradation|soil degradation]] and biotic diseases. Increased mortality and decreased increment generated widespread concern, especially after reinforcement by other environmental stresses.

More or less uneven-aged, mixed forests of preponderantly native species, on the other hand, treated along natural lines, have proved to be healthier and more resistant to all kinds of external dangers; and in the long run such stands are more productive and easier to protect.

However, irregular stands of this type are definitely more difficult to manage—new methods and techniques had to be sought particularly for the establishment of inventories, as well as increment control and yield regulation. In Germany, for instance, since the beginning of the nineteenth century under the influence of G.L. Hartig (1764–1837), yield regulation has been effected almost exclusively by allotment or formula methods based on the conception of the uniform normal forest with a regular succession of cutting areas.

In France, on the other hand, efforts were made to apply another kind of forest management, one that aimed to bring all parts of the forest to a state of highest productive capacity in perpetuity. In 1878, the French forester A. Gurnaud (1825–1898) published a description of a {{Lang|fr|méthode du contrôle}} for determining increment and yield. The method was based on the fact that through careful, selective harvesting, the productivity of the residual stand can be improved, because timber is removed as a cultural operation. In this method, the increment of stands is accurately determined periodically with the object of gradually converting the forest, through selective management and continuous experimentation, to a condition of equilibrium at maximum productive capacity.

Henri Biolley (1858–1939) was the first to apply Gurnaud's inspired ideas to practical forestry. From 1890 on, he managed the forests of his Swiss district according to these principles, devoting himself for almost 50 years to the study of increment and a treatment of stands directed towards the highest production, and proving the practicability of the check method. In 1920, he published this study giving a theoretical basis of management of forests under the check method, describing the procedures to be applied in practice (which he partly developed and simplified), and evaluating the results.

Biolley's pioneering work formed the basis upon which most Swiss forest management practices were later developed, and his ideas have been generally accepted. Today, with the trend of intensifying forest management and productivity in most countries, the ideas and application of careful, continuous treatment of stands with the aid of the volume check method are meeting with ever-growing interest. In Britain and Ireland, for example, there is increased application of [[continuous cover forestry]] principles to create permanently irregular structures in many woodlands.<ref>Helliwell, R., and E. R. Wilson. (2012). Continuous cover forestry in Britain: challenges and opportunities..Quarterly Journal of Forestry 106(3): 214-224 [https://www.researchgate.net/publication/260031518_Continuous_cover_forestry_in_Britain_challenges_and_opportunities]</ref>

===[[Patch cut]]===

===Row and broadcast seeding===
Spot and row seeders use less seed that does broadcast ground or aerial seeding but may induce clumping. Row and spot seeding confer greater ability to control seed placement than does broadcast seeding. Also, only a small percentage of the total area needs to be treated.

In the aspen type of the Great Lakes region, direct sowing of the seed of [[Pinophyta|conifers]] has usually failed.<ref name="kitt" /> However, Gardner (1980)<ref name="gard">Gardner, A.C. 1980. Regeneration problems and options for white spruce on river floodplains in the Yukon Territory. p. 19–24 ''in'' Murray, M.; Van Veldhuizen, R.M. (Eds.). Forest Regeneration at High,</ref> after trials in Yukon, which included broadcast seeding of white spruce seed at 2.24&nbsp;kg/ha that secured 66.5% stocking in the Scarified Spring Broadcast treatment three years after seeding, concluded that the technique held "considerable promise".

===[[Seedstock|Seed-tree]]===
An even-aged regeneration method that retains widely spaced residual trees in order to provide uniform seed dispersal across a harvested area. In the seed-tree method, 2-12 seed trees per acre (5-30/ha) are left standing in order to regenerate the forest. They will be retained until regeneration has become established at which point they may be removed. It may not always be economically viable or biologically desirable to re-enter the stand to remove the remaining seed trees. Seed-tree cuts can also be viewed as a clearcut with natural regeneration and can also have all of the problems associated with clearcutting. This method is most suited for light-seeded species and those not prone to [[windthrow]].

===Selection systems===
Selection systems are appropriate where uneven stand structure is desired, particularly where the need to retain [[Continuous Cover Forestry|continuous cover forest]] for aesthetic or environmental reasons outweighs other management considerations. Selection logging has been suggested as being of greater utility than shelterwood systems in regenerating old-growth Engelmann Spruce Sub-alpine Fir (ESSF) stands in southern British Columbia.<ref name="weet">Weetman, G.; Vyse, A. 1990. Natural regeneration. p. 118–130 ''in ''Lavender, D.P.; Parish, R.; Johnson, C.M.; Montgomery, G.; Vyse, A.; Willis, R.A.; Winston, D. (Eds.). Regenerating British Columbia's Forests. Univ. B.C. Press, Vancouver BC. (Cited in Coates et al. 1994).</ref> In most areas, selection logging favours regeneration of fir more than the more light-demanding spruce.<ref name="alex4">Alexander, R.R. 1987. Ecology, silviculture, and management of the Engelmann spruce–subalpine fir type in the central and southern Rocky Mountains. USDA, For. Serv., Washington DC, Agric. Handb. 659. 144 p.</ref><ref name="coat" /><ref name="glew">Glew, D.R. 1963. The results of stand treatment in the white spruce–alpine fir type of the northern interior of British Columbia. B.C. Dep. Lands For. Water Resour., B.C. For. Serv., Victoria BC, For. Manage. Note 1. 27 p. (Cited in Coates et al. 1994).</ref> In some areas, selection logging can be expected to favour spruce over less tolerant hardwood species (Zasada 1972)<ref name="zas1" /> or lodgepole pine.<ref name="coat">{{cite journal|last1=Coates|first1=K. D.|last2=Haeussler|first2=S.|last3=Lindeburgh|first3=S.|last4=Pojar|first4=R.|last5=Stock|first5=A. J.|date=1994|title=Ecology and silviculture of interior spruce in British Columbia|url=https://www.for.gov.bc.ca/hfd/pubs/Docs/Frr/FRR220.pdf|journal=FRDA Report|volume=220|issn=0835-0752}}</ref>

===Shelter spot seeding===
The use of shelters to improve germination and survival in spot seedings seeks to capture the benefits of [[greenhouse]] culture, albeit miniature. The Hakmet seed shelter, for instance, is a semi-transparent plastic cone 8&nbsp;cm high, with openings of 7&nbsp;cm diameter in the 7.5&nbsp;cm diameter base and 17&nbsp;mm diameter in the 24&nbsp;mm diameter top.<ref name="lah">Lähde, F. and Tuohisaari, O. 1976. An ecological study on the effects of shelters on germination and germling development of Scotch pine, Norway spruce and Siberian larch. Comm. Inst. For. Reprint 88.1. 35 p.</ref> This miniature greenhouse increases air humidity, reduces soil desiccation, and raises air and soil temperatures to levels more favourable to germination and [[seedling]] growth than those offered by unprotected conditions. The shelter is designed to break down after a few years of exposure to ultraviolet radiation.

Seed shelters and spring sowing significantly improved stocking compared with bare spot seeding, but sheltering did not significantly improve growth. Stocking of bare seedspots was extremely low, possibly due to smothering of seedlings by abundant broadleaf and herbaceous litter, particularly that from aspen and red raspberry, and exacerbated by strong competition from graminoids and raspberry.

Cone shelters (Cerkon™) usually produced greater survival than unsheltered seeding on scarified seedspots in trials of direct seeding techniques in interior Alaska, and funnel shelters (Cerbel™) usually produced greater survival than unsheltered seeding on non-scarified seedspots.<ref name="put2">Putman, W.E.; Zasada, J.C. 1986. Direct seeding techniques to regenerate white spruce in interior Alaska. Can. J. For. Res. 16(3):660–664.</ref> Both shelter types are manufactured by AB Cerbo in Trollhättan, Sweden. Both are made of light-degradable, white, opaque plastic, and are 8&nbsp;cm high when installed.

White spruce seed was sown in Alaska on a burned site in summer 1984, and protected by white plastic cones on small spots scarified by hand, or by white funnels placed directly into the residual ash and organic material.<ref name="put1">Putman, W.E.; Zasada, J.C. 1985. Raven damage to plastic seeding shelters in interior Alaska. North. J. Appl. For. 2(2):41–43. (Cited in Coates et al. 1994).</ref> A group of six ravens (''Corvus corax'') was observed in the area about one week after sowing was completed in mid-June. Damage averaged 68% with cones and 50% with funnels on an upland area, and 26% with funnels on a floodplain area. Damage by ravens was only 0.13% on unburned but otherwise similar areas.

In seeding trials in Manitoba between 1960 and 1966 aimed at converting [[aspen]] stands to spruce–aspen mixedwoods, 1961 scarification in the [[Duck Mountain Provincial Forest]] remained receptive to natural seeding for many years.<ref name="dyck">Dyck, J.R. 1994. Converting aspen stands to white spruce–aspen mixedwoods by planting and seeding, Manitoba: Manitoba forestry demonstration areas. Can./Manitoba Partnership in For., unumbered rep. 28 p.</ref>

===[[Shelterwood cutting|Shelterwood]]===
In general terms, the shelterwood system is a series of partial cuts that removes the trees of an existing stand over several years and eventually culminates in a final cut that creates a new even-aged stand.<ref>3 Brose, Patrick H. 2008; 3 Brose, Patrick H. 2008;</ref> It is an even-aged regeneration method that removes trees in a series of three harvests: 1) Preparatory cut; 2) Establishment cut; and 3) Removal cut. The success of practising a shelterwood system is closely related to: 1. the length of the regeneration period, i.e. the time from the shelterwood cutting to the date when a new generation of trees has been established; 2.the quality of the new tree stand with respect to stand density and growth; and 3.the value increment of the shelter trees. Information on the establishment, survival and growth of seedlings influenced by the cover of shelter trees, as well as on the growth of these trees, is needed as a basis for modelling the economic return of practising a shelterwood system.<ref>4 Holgén, Per 2000; 4 Holgén, Per 2000;</ref> The method's objective is to establish new forest reproduction under the shelter of the retained trees. Unlike the seed-tree method, residual trees alter [[understory]] environmental conditions (i.e. sunlight, temperature, and moisture) that influence tree seedling growth. This method can also find a middle ground with the light ambiance by having less light accessible to competitors while still being able to provide enough light for tree regeneration.<ref>''Survival and Growth of Under-Planted Trees: A Meta-Analysis across Four Biomes''.
 Alain Paquette, André Bouchard and Alain Cogliastro
 Ecological Applications, Vol. 16, No. 4 (Aug., 2006), pp. 1575-1589</ref> Hence, shelterwood methods are most often chosen for site types characterized by extreme conditions, in order to create a new tree generation within a reasonable time period. These conditions are valid foremost on level ground sites which are either dry and poor or moist and fertile.<ref>4 Holgén, Per 2000;</ref>

===Shelterwood systems===
Shelterwood systems involve two, three, or exceptionally more partial cuttings. A final cut is made once adequate natural [[Regeneration (biology)|regeneration]] has been obtained. The shelterwood system is most commonly applied as a two-cut uniform shelterwood, first an initial regeneration (seed) cut, the second a final harvest cut. In stands less than 100 years old, a light preparatory cut can be useful.<ref name="zas1" /> A series of intermediate cuts at intervals of 10–20 years has been recommended for intensively managed stands.<ref name="alex4" />

From operational or economic standpoints, however, there are disadvantages to the shelterwood system: harvesting costs are higher; trees left for deferred cutting may be damaged during the regeneration cut or related extraction operations; the increased risk of blowdown threatens the seed source; damage from bark beetles is likely to increase; regeneration may be damaged during the final cut and related extraction operations; the difficulty of any site preparation would be increased; and incidental damage to regeneration might be caused by any site preparation operations.<ref name="alex3" /><ref name="Day 1970">Day, M.W.; Rudolph, V.J. 1970. Development of a white spruce plantation. Michigan State Univ., Agric. Exp. Sta., East Lansing MI, Res. Pap. 111. 4 p.</ref><ref name="zas1">Zasada, J.C. 1972. Guidelines for obtaining natural regeneration of white spruce in Alaska. USDA, For. Serv., Pacific Northwest For. Range Exp. Sta., Portland OR. 16 p.</ref><ref name="Baldwin 1977">Baldwin, V.C. 1977. Regeneration following shelterwood cutting in a New Brunswick softwood stand. Can. Dep. Fish. & Environ., Can. For. Serv., Fredericton NB, Inf. Rep. M-X-76. 23 p.</ref><ref name="alex5">Alexander, R.R. 1973. Partial cutting in old-growth spruce-fir. USDA For. Serv., Rocky Mountain and Range Exp. Sta., Fort Collins, CO, Research Paper RM-100. 16 p.</ref>

===[[Selection cutting#Single-tree selection|Single-tree selection]]===
The single-tree selection method is an uneven-aged regeneration method most suitable when [[Shade tolerance|shade tolerant]] species regeneration is desired. It is typical for older and diseased trees to be removed, thus thinning the stand and allowing for younger, healthy trees to grow. Single-tree selection can be very difficult to implement in dense or sensitive stands and residual stand damage can occur. This method is also disturbs the canopy layer the least out of all other methods.<ref>''Conservation Approaches for Woody, Early Successional Communities in the Eastern United States''. Frank R. Thompson, III and Richard M. DeGraaf
 Wildlife Society Bulletin, Vol. 29, No. 2 (Summer, 2001), pp. 483-494. Web. 4 October 2013.</ref>

===Spot seeding===
Spot seeding was found to be the most economical and reliable of the direct seeding methods for converting [[aspen]] and [[Betula papyrifera|paper birch]] to [[spruce]] and [[pine]].<ref name="robert">Robertson, W.M. 1927. Cutting for reproduction in spruce stands. For. Chron. 3(3):7–10.</ref> In the Chippewa National Forest (Lake States), seed-spot sowing of 10 seeds each of white spruce and white pine under 40-year aspen after different degrees of cutting on gave second-season results clearly indicating the need to remove or disturb the forest floor to obtain germination of seeded white spruce and white pine.<ref name="kitt">Kittredge, J. Jr.; Gevorkiantz, S. R. 1929. Forest possibilities of aspen lands in the Lake States. Minnesota Agricultural Exp. Sta., Minneapolis, Minnesota, Technical Bulletin 60.</ref>

Spot seeding of [[Pinophyta|coniferous seed]], including white spruce, has had occasional success, but several constraining factors commonly limit [[germination]] success: the drying out of the forest floor before the roots of germinants reach underlying moisture reserves; and, particularly under hardwoods, the smothering of small seedlings by snow-pressed leaf litter and lesser vegetation. Kittredge and Gervorkiantz (1929)<ref name="kitt"/> determined that removal of the aspen forest floor increased germination percentage after the second season in seed spots of both white pine and white spruce, in four plots, from 2.5% to 5%, from 8% to 22%, from 1% to 9.5%, and from 0% to 15%.

Spot seeding requires less seed than broadcast seeding and tends to achieve more uniform spacing, albeit sometimes with clumping. The devices used in Ontario for manual spot seeding are the "oil can" seeder, seeding sticks, and shakers.<ref name="scott">Scott, J.D. 1970. Direct seeding in Ontario. For. Chron. 46(6):453–457.</ref> The oil can is a container fitted with a long spout through which a predetermined number of seeds are released with each flick of the seeder.

===Strip cutting===
Harvesting cutblocks where only a portion of the trees are to be removed is very different from clearcutting.<ref name="saud"/> First, trails must be located to provide access for the felling and skidding/forwarding equipment. These trails must be carefully located to ensure that the trees remaining meet the desired quality criteria and stocking density. Second, the equipment must not damage the residual stand. The further desiderata are outlined by Sauder (1995).<ref name="saud" />

The dearth of seed and a deficiency of receptive seedbeds were recognized as major reasons for the lack of success of clearcut harvesting. One remedy attempted in British Columbia and Alberta has been alternate strip cutting.<ref name="butt">Butt, G. 1988. Backlog forest land rehabilitation in the SBS and BWBS zones in the northern interior of British Columbia. Can./B.C. FRDA Rep. 023. 125 p.</ref> The greater seed source from uncut trees between the cut strips, and the disturbance to the forest floor within the cut strips could be expected to increase the amount of natural regeneration. Trees were cut to a diameter limit in the cut strips, but large trees in the leave strips often proved too much of a temptation and were cut too,<ref name="coat" /> thus removing those trees that would otherwise have been the major source of seed.

An unfortunate consequence of strip thinning was the build-up of spruce beetle populations. Shaded slash from the initial cut, together with an increase in the number of windthrown trees in the leave strips, provided conditions ideally suited to the beetle.<ref name="dye">Dyer, E.D.A.; Taylor, D.W. 1968. Attractiveness of logs containing female spruce beetles ''Dendroctontus obesus'' (ColeopteraL Scolytidae). Can. Entomol 100: 769-776.</ref>

===Underplanting===
DeLong et al. (1991)<ref name="del">DeLong, C. 1991. Dynamics of boreal mixedwood ecosystems. p.30–31 ''in'' Northern Mixedwood ‘89: Proceedings of a symposium held at Fort St. John, B.C., Sept. 1989. A. Shortreid (Ed.), For. Can., Pacific For. Centre, Victoria BC, FRDA Report 164.</ref> suggested underplanting 30- to 40-year-old [[aspen]] stands, on the basis of the success of natural spruce in regenerating under stands of such stands: "By planting, spacing can be controlled enabling easier protection of the spruce during stand entry for harvesting of the aspen overstorey".

===[[Variable retention]]===
A harvesting and regeneration method which is a relatively new silvicultural system that retains forest structural elements (stumps, logs, snags, trees, understory species and undisturbed layers of forest floor) for at least one rotation in order to preserve environmental values associated with structurally complex forests.<ref>Kohm, K. A, and Franklin, J. F., Creating a forestry for the 21st century: the science of ecosystem management. Island Press. 1997, {{ISBN|978-1-55963-399-4}}</ref>

"Uneven-aged and even-aged methods differ in the scale and intensity of disturbance. Uneven-aged methods maintain a mix of tree sizes or ages within a habitat patch by periodically harvesting individual or small groups of trees, Even-aged methods harvest most or all of the overstory and create a fairly uniform habitat patch dominated by trees of the same age".<ref>''The Role of Disturbance in the Ecology and Conservation of Birds''
 Jeffrey D. Brawn, Scott K. Robinson and Frank R. Thompson III
 Annual Review of Ecology and Systematics, Vol. 32, (2001), pp. 251-276. Web. 4 October 2013.</ref> Even-aged management systems have been the prime methods to use when studying the effects on birds.<ref>''Effects of Selection Cutting on Bird Communities in Contiguous Eastern Hardwood Forests''
. Andrew P. Jobes, Erica Nol and Dennis R. Voigt
 The Journal of Wildlife Management, Vol. 68, No. 1 (Jan., 2004), pp. 51-60. Web. 4 October 2013.</ref>

==Mortality==

A survey in 1955–56 to determine survival, development, and the reasons for success or failure of [[Pinophyta|conifer]] pulpwood plantations (mainly of white spruce) in Ontario and Quebec up to 32 years old found that the bulk of the mortality occurred within the first four years of planting, unfavourable site and [[climate]] being the main causes of failure.<ref name="stie2">Stiell, W.M. 1958. Pulpwood plantations in Ontario and Quebec. Can. Pulp Pap. Assoc., Woodlands Section, Index No. 1770 (F-2). 42 p.</ref>

==Advance growth==

Naturally regenerated trees in an understorey prior to harvesting constitute a classic case of good news and bad news. Understorey white spruce is of particular importance in mixedwoods dominated by [[aspen]], as in the B15, B18a, and B19a Sections of Manitoba,<ref name="rowe2">Rowe, J.S 1972. Forest regions of Canada. Can. Dep. Environ., Can. For. Serv., Ottawa ON, Publ. 1300. 172 p.</ref> and elsewhere. Until the latter part of the last century, white spruce understorey was mostly viewed as money in the bank on a long-term, low interest deposit, with final yield to be realized after slow natural succession,<ref name="brace3">Brace, L.; Bella, I. 1988. Understanding the understorey: dilemma and opportunity. ''In'' White spruce understories. Canada–Alberta Agreement, Projects 1480, 1488, 20204. For. Can., Northern For. Centre, Edmonton AB. (Cited in Coates et al. 1994)</ref> but the resource became increasingly threatened with the intensification of harvesting of aspen. White spruce plantations on mixedwood sites proved expensive, risky, and generally unsuccessful.<ref name="brace3" /> This prompted efforts to see what might be done about growing aspen and white spruce on the same landbase by protecting existing white spruce advance growth, leaving a range of viable crop trees during the first cut, then harvesting both [[hardwood]]s and spruce in the final cut. Information about the understorey component is critical to spruce management planning. The ability of then current harvesting technology and crews employed to provide adequate protection for white spruce understories was questioned by Brace and Bella. Specialized equipment and training, perhaps with financial incentives, may be needed to develop procedures that would confer the degree of protection needed for the system to be feasible. Effective understorey management planning requires more than improved mixedwood inventory.

Avoidance of damage to the understorey will always be a desideratum. Sauder's (1990)<ref name="saudnew">Sauder, E.A. 1990. Mixedwood harvesting. section B In White spruce understories, Canada–Alberta Agreement, Projects 1480, 1488, 20204. For. Can., Northern For. Centre, Edmonton AB, various pagination.</ref> paper on mixedwood harvesting describes studies designed to evaluate methods of reducing non-trivial damage to understorey residuals that would compromise their chance of becoming a future crop tree. Sauder concluded that: (1) operational measures that protected residual stems may not unduly increase costs, (2) all felling, conifers and hardwoods, needs to be done in one operation to minimize the entry of the feller-buncher into the residual stand, (3) several operational procedures can reduce understorey damage, some of them without incurring extra costs, and (4) successful harvesting of treatment blocks depends primarily on the intelligent location of skid trails and landings. In summary, the key to protecting the white spruce understorey without sacrificing logging efficiency is a combination of good planning, good supervision, the use of appropriate equipment, and having conscientious, well-trained operators.Even the best plan will not reduce understorey damage unless its implementation is supervised.<ref name="saud2">Sauder, E.A.; Sinclair, A.W.J. 1989. Harvesting in the mixedwood forest. Paper included in White spruce understories, Canada–Alberta Agreement, Projects 1480, 1488, 20204. For. Can., Northern For. Centre, Edmonton AB.</ref>

New stands need to be established to provide for future supply of commercial white spruce from 150,000 ha of [[Taiga|boreal]] mixedwoods in four of Rowe's (1972)<ref name="rowe2" /> regional Forest Sections straddling Alberta, Saskatchewan, and Manitoba, roughly from Peace River AB to Brandon MB.<ref name="brace1">Brace, L. 1989. Protecting understorey white spruce when harvesting aspen. ''In'' White spruce understories, Canada–Alberta Agreement, Projects 1480, 1488, 20204. For. Can., Northern For. Centre, Edmonton AB.</ref> In the 1980s, with harvesting using conventional equipment and procedures, a dramatic increase in the demand for aspen posed a serious problem for the associated spruce understorey. Formerly, white spruce in the understories had developed to commercial size through natural succession under the protection of the hardwoods. Brace articulated a widespread concern: "The need for protection of spruce as a component of boreal mixedwoods goes beyond concern for the future commercial softwood timber supply. Concerns also include fisheries and wildlife habitat, aesthetics and recreation, a general dissatisfaction with clearcutting in mixedwoods and a strong interest in mixedwood perpetuation, as expressed recently in 41 public meetings on forestry development in northern Alberta...".<ref name="brace1" />

On the basis of tests of three logging systems in Alberta, Brace (1990)<ref name="brace2">Brace, L. 1990. A test of three logging systems in Alberta. Paper included in White spruce understories, Canada–Alberta Agreement, Projects 1480, 1488, 20204. For. Can., Northern For. Centre, Edmonton AB.</ref> affirmed that significant amounts of understorey can be retained using any of those systems provided that sufficient effort is directed towards protection. Potential benefits would include increased short-term softwood timber supply, improved wildlife habitat and cutblock aesthetics, as well as reduced public criticism of previous logging practices. Stewart et al. (2001)<ref name="stew">Stewart, J.D.; Landhäusser, S.M.; Stadt, K.J.; Lieffers, V.J. 2001. Predicting natural regeneration of white spruce in boreal mixedwood understories. For. Chron. 77(6):1006–1013.</ref> developed statistical models to predict the natural establishment and height growth of understorey white spruce in the boreal mixedwood forest in Alberta using data from 148 permanent sample plots and supplementary information about height growth of white spruce regeneration and the amount and type of available substrate. A discriminant model correctly classified 73% of the sites as to presence or absence of a white spruce understorey, based on the amount of spruce basal area, rotten wood, ecological nutrient regime, soil clay fraction, and elevation, although it explained only 30% of the variation in the data. On sites with a white spruce understorey, a regression model related the abundance of regeneration to rotten wood cover, spruce basal area, pine basal area, soil clay fraction, and grass cover (R² = 0.36). About half the seedlings surveyed grew on rotten wood, and only 3% on mineral soil, and seedlings were ten times more likely to have established on these substrates than on litter. Exposed mineral soil covered only 0.3% of the observed transect area.

===Advance growth management===

''Advance growth management'', i.e., the use of suppressed understorey trees, can reduce reforestation costs, shorten rotations, avoid denuding the site of trees, and also reduce adverse impacts on aesthetic, wildlife, and watershed values.<ref name="McCaughey 1982">McCaughey, W.W.; Schmidt, W.C. 1982. Understory tree release following harvest cutting in spruce–fir forests of the Intermountain West. USDA, For. Serv., Intermountain For. Range Exp. Sta., Res. Pap. INT-285. Cited in Coates et al. 1994).</ref><ref name="john">Johnstone, W.D. 1978. Growth of fir and spruce advance growth and logging residuals following logging in west-central Alberta.  Can. Dep. Environ., Can. For. Serv., Northern For. Res. Centre, Edmonton AB, Inf. Rep. NOR-X-203. 16 p.</ref> To be of value, advance growth must have acceptable [[species composition]] and distribution, have potential for growth following release, and not be vulnerable to excessive damage from logging.

The age of advance growth is difficult to estimate from its size,<ref name="alex6">Alexander, R.R. 1958. Silvical characteristics of Engelmann spruce. USDA, For. Serv., Rocky Mountain For. Range Exp. Sta., Fort Collins CO, Paper 31. 20 p.</ref> as white that appears to be two- to three-year-old may well be more than twenty years old.<ref name="Ball 1979">Ball, W.J.; Kolabinski, V.S. 1979. An aerial reconnaissance of softwood regeneration on mixedwood sites in Saskatchewan. Can. Dep. Environ., Can. For. Serv., Northern For. Res. Centre, Edmonton AB, Inf. Rep. NOR-X-216. 14 p.</ref> However, age does not seem to determine the ability of advance growth of spruce to respond to release,<ref name="McCaughey 1982" /><ref name="john" /><ref name="McCaughey 1988">McCaughey, W.W.; Ferguson, D.E. 1988. Response of advance regeneration to release in the Inland Mountain West: a summary. p. 255–266 ''in ''Schmidt, W.C. (Compiler). Proc. Future Forests of the Mountain West: A Stand Culture Symp., Sept./Oct. 1986, Missoula MT. USDA, For. Serv., Intermount. Res. Sta., Ogden UT, Gen. Tech. Rep. INT-243. 402 p.</ref> and trees older than 100 years have shown rapid rates of growth after release. Nor is there a clear relationship between the size of advance growth and its growth rate when released.

Where advance growth consists of both [[spruce]] and [[fir]], the latter is apt to respond to release more quickly than the former, whereas spruce does respond.<ref name="Smith 1979">Smith, R.B.; Wass, E.F. 1979. Tree growth on and adjacent to contour skid roads in the subalpine zone, southeastern British Columbia. Can. Dep. Environ., Can. For. Serv., Victoria BC, Report BC-R-2. 26 p.</ref><ref name="stett">Stettler, R.F. 1958. Development of a residual stand of interior spruce–alpine fir during the first twenty-eight years following cutting to a 12-inch diameter limit. For. Serv., Victoria BC, Res. Note 34. 15 p. [Coates et al. 1994]</ref> If the ratio of fir to spruce is large, however, the greater responsiveness to release of fir may subject the spruce to competition severe enough to negate much of the effect of release treatment. Even temporary relief from [[shrub]] competition has increased height growth rates of white spruce in northwestern New Brunswick, enabling the spruce to overtop the shrubs.<ref name="bask">Baskerville, G.L. 1961. Response of young fir and spruce to release from shrub competition. Can. Dep. Northern Affairs and National Resources, For. Branch, Ottawa ON, For. Res. Div., Tech. Note 98. 14 p. (Cited in Coates et al. 1994)</ref>

==Site preparation==

Site preparation is any of various treatments applied to a site in order to ready it for seeding or planting. The purpose is to facilitate the [[Regeneration (biology)|regeneration]] of that site by the chosen method. Site preparation may be designed to achieve, singly or in any combination: improved access, by reducing or rearranging slash, and amelioration of adverse forest floor, soil, vegetation, or other biotic factors. Site preparation is undertaken to ameliorate one or more constraints that would otherwise be likely to thwart the objectives of management. A valuable bibliography on the effects of soil temperature and site preparation on subalpine and [[Taiga|boreal]] tree species has been prepared by McKinnon et al. (2002).<ref name="mck">McKinnon, L.M.; Mitchell, A.K.; Vyse, A. 2002. The effects of soil temperature and site preparation on subalpine and boreal tree species: a bibliography. Nat. Resour., Can., Can. For. Serv., Victoria BC, Inf. Rep. BC-X-394. 29 p.</ref>

Site preparation is the work that is done before a forest area is regenerated. Some types of site preparation are burning.

===Burning===

Broadcast burning is commonly used to prepare clearcut sites for planting, e.g., in central British Columbia,<ref name="Macadam 1987">Macadam, A.M. 1987. Effects of broadcast slash burning on fuels and soil chemical properties in the sub-boreal spruce zone of central British Columbia. Can. J. For. Res. 17(12):1577–1584.</ref> and in the temperate region of North America generally.<ref name="kii">Kiil, A.D.; Chrosciewicz, Z. 1970. Prescribed fire – its place in reforestation. For. Chron. 46:448–451.</ref>

Prescribed burning is carried out primarily for slash hazard reduction and to improve site conditions for regeneration; all or some of the following benefits may accrue:

:a) Reduction of logging slash, plant competition, and humus prior to direct seeding, planting, scarifying or in anticipation of natural seeding in partially cut stands or in connection with seed-tree systems.
:b) Reduction or elimination of unwanted forest cover prior to planting or seeding, or prior to preliminary scarification thereto.
:c) Reduction of humus on cold, moist sites to favour regeneration.
:d) Reduction or elimination of slash, grass, or brush fuels from strategic areas around forested land to reduce the chances of damage by wildfire.

Prescribed burning for preparing sites for direct seeding was tried on a few occasions in Ontario, but none of the burns was hot enough to produce a seedbed that was adequate without supplementary mechanical site preparation.<ref name="scott"/>

Changes in soil chemical properties associated with burning include significantly increased pH, which Macadam (1987)<ref name="Macadam 1987" /> in the Sub-boreal Spruce Zone of central British Columbia found persisting more than a year after the burn. Average fuel consumption was 20 to 24 t/ha and the forest floor depth was reduced by 28% to 36%. The increases correlated well with the amounts of slash (both total and ≥7&nbsp;cm diameter) consumed. The change in pH depends on the severity of the burn and the amount consumed; the increase can be as much as two units, a hundred-fold change.<ref name="holt">Holt, L. 1955. White spruce seedbeds as related to natural regeneration. Pulp Paper Res. Instit. Can., Montreal QC. 28 p.</ref> Deficiencies of copper and iron in the foliage of white spruce on burned clearcuts in central British Columbia might be attributable to elevated pH levels.<ref name="Ballard 1985">Ballard, T.M. 1985. Spruce nutrition problems in the central interior and their relationship with site preparation. Proc. Interior spruce seedling performance: state of the art Symposium. Northern Silviculture Committee Workshop, Feb. 1985, Prince George BC.</ref>

Even a broadcast slash fire in a clearcut does not give a uniform burn over the whole area. Tarrant (1954),<ref name="tarr">Tarrant, R.F. 1954. Effect of slash burning on soil pH. USDA, For. Serv., Pacific Northwest For. and Range Exp. Sta., Portland OR, Res. Note 102. 5 p.</ref> for instance, found only 4% of a 140-ha slash burn had burned severely, 47% had burned lightly, and 49% was unburned. Burning after windrowing obviously accentuates the subsequent heterogeneity.

Marked increases in exchangeable calcium also correlated with the amount of slash at least 7&nbsp;cm in diameter consumed.<ref name="Macadam 1987" /> Phosphorus availability also increased, both in the forest floor and in the 0&nbsp;cm to 15&nbsp;cm mineral soil layer, and the increase was still evident, albeit somewhat diminished, 21 months after burning. However, in another study<ref name="tay">Taylor, S.W.; Feller, M.C. 1987. Initial effects of slashburning on the nutrient status of Sub-boreal Spruce Zone ecosystems. ''In'' Papers presented at the Fire Management Symposium, April 1987, Prince George BC, Central Interior Fire Protection Committee, Smithers BC.</ref> in the same Sub-boreal Spruce Zone found that although it increased immediately after the burn, phosphorus availability had dropped to below pre-burn levels within nine months.

Nitrogen will be lost from the site by burning,<ref name="Macadam 1987" /><ref name="tay" /><ref name="litt">Little, S.N.; Klock, G.O. 1985. The influence of residue removal and prescribed fire on distribution of forest nutrients. USDA, For. Serv., Res. Pap. PNW-333.</ref> though concentrations in remaining forest floor were found by Macadam (1987)<ref name="Macadam 1987" /> to have increased in two of six plots, the others showing decreases. Nutrient losses may be outweighed, at least in the short term, by improved soil microclimate through the reduced thickness of forest floor where low soil temperatures are a limiting factor.

The ''Picea/Abies'' forests of the Alberta foothills are often characterized by deep accumulations of organic matter on the soil surface and cold soil temperatures, both of which make reforestation difficult and result in a general deterioration in site productivity; Endean and Johnstone (1974)<ref name="end">Endean, F.; Johnstone, W.D. 1974. Prescribed fire and regeneration on clearcut spruce–fir sites in the foothills of Alberta. Environ. Can., Can. For. Serv., Northern For. Res. Centre, Edmonton AB, Inf. Rep. NOR-X-126. 33 p.</ref> describe experiments to test prescribed burning as a means of seedbed preparation and site amelioration on representative clear-felled ''Picea/Abies'' areas. Results showed that, in general, prescribed burning did not reduce organic layers satisfactorily, nor did it increase soil temperature, on the sites tested. Increases in seedling establishment, survival, and growth on the burned sites were probably the result of slight reductions in the depth of the organic layer, minor increases in soil temperature, and marked improvements in the efficiency of the planting crews. Results also suggested that the process of site deterioration has not been reversed by the burning treatments applied.

===Ameliorative intervention===

Slash weight (the oven-dry weight of the entire crown and that portion of the stem < 4 inches in diameter) and size distribution are major factors influencing the [[Wildfire|forest fire]] hazard on harvested sites.<ref name="kii1">Kiil, A.D. 1965. Weight and size distribution of slash of white spruce and lodgepole pine. For. Chron. 41:432–437.</ref> Forest managers interested in the application of prescribed burning for hazard reduction and silviculture, were shown a method for quantifying the slash load by Kiil (1968).<ref name="kii2">Kiil, A.D. 1968. Weight of the fuel complex in 70-year-old lodgepole pine stands of different densities. Department of Forestry and Rural Development, Forest Research Laboratory, Calgary, Alberta. Departmental Publication 1228. 13 p.</ref> In west-central Alberta, he felled, measured, and weighed 60 white spruce, graphed (a) slash weight per merchantable unit volume against diameter at breast height (dbh), and (b) weight of fine slash (<1.27&nbsp;cm) also against dbh, and produced a table of slash weight and size distribution on one acre of a hypothetical stand of white spruce. When the diameter distribution of a stand is unknown, an estimate of slash weight and size distribution can be obtained from average stand diameter, number of trees per unit area, and merchantable cubic foot volume. The sample trees in Kiil's study had full symmetrical crowns. Densely growing trees with short and often irregular crowns would probably be overestimated; open-grown trees with long crowns would probably be underestimated.

The need to provide shade for young outplants of [[Picea engelmannii|Engelmann spruce]] in the high [[Rocky Mountains]] is emphasized by the U.S. Forest Service. Acceptable planting spots are defined as microsites on the north and east sides of down logs, stumps, or slash, and lying in the shadow cast by such material.<ref name="ronco">Ronco, F. 1975. Diagnosis: sunburned trees. J. For. 73(1):31–35. (Cited in Coates et al. 1994).</ref> Where the objectives of management specify more uniform spacing, or higher densities, than obtainable from an existing distribution of shade-providing material, redistribution or importing of such material has been undertaken.

===Access===

Site preparation on some sites might be done simply to facilitate access by planters, or to improve access and increase the number or distribution of microsites suitable for planting or seeding.

Wang et al. (2000)<ref name="wang">Wang, G.G.; Siemens, A.; Keenan, V.; Philippot, D. 2000. Survival and growth of black and white spruce seedlings in relation to stock type, site preparation and plantation type in southeastern Manitoba. For. Chron. 76(5):775–782.</ref> determined field performance of white and black spruces eight and nine years after outplanting on boreal mixedwood sites following site preparation (Donaren disc trenching versus no trenching) in two plantation types (open versus sheltered) in southeastern Manitoba. Donaren trenching slightly reduced the mortality of black spruce but significantly increased the mortality of white spruce. Significant difference in height was found between open and sheltered plantations for black spruce but not for white spruce, and root collar diameter in sheltered plantations was significantly larger than in open plantations for black spruce but not for white spruce. Black spruce open plantation had significantly smaller volume (97&nbsp;cm<sup>3</sup>) compared with black spruce sheltered (210&nbsp;cm<sup>3</sup>), as well as white spruce open (175&nbsp;cm<sup>3</sup>) and sheltered (229&nbsp;cm<sup>3</sup>) plantations. White spruce open plantations also had smaller volume than white spruce sheltered plantations. For transplant stock, strip plantations had a significantly higher volume (329&nbsp;cm<sup>3</sup>) than open plantations (204&nbsp;cm<sup>3</sup>). Wang et al. (2000)<ref name="wang" /> recommended that sheltered plantation site preparation should be used.

===Mechanical===

Up to 1970, no "sophisticated" site preparation equipment had become operational in Ontario,<ref name="hall">Hall, J. 1970. Site preparation in Ontario. For. Chron. 46:445–447.</ref> but the need for more efficacious and versatile equipment was increasingly recognized. By this time, improvements were being made to equipment originally developed by field staff, and field testing of equipment from other sources was increasing.

According to J. Hall (1970),<ref name="hall" /> in Ontario at least, the most widely used site preparation technique was post-harvest mechanical scarification by equipment front-mounted on a bulldozer (blade, rake, V-plow, or teeth), or dragged behind a tractor (Imsett or S.F.I. scarifier, or rolling chopper). Drag type units designed and constructed by Ontario's Department of Lands and Forests used anchor chain or tractor pads separately or in combination, or were finned steel drums or barrels of various sizes and used in sets alone or combined with tractor pad or anchor chain units.

J. Hall's (1970)<ref name="hall" /> report on the state of site preparation in Ontario noted that blades and rakes were found to be well suited to post-cut scarification in tolerant [[hardwood]] stands for natural regeneration of [[Betula alleghaniensis|yellow birch]]. Plows were most effective for treating dense brush prior to planting, often in conjunction with a planting machine. Scarifying teeth, e.g., Young's teeth, were sometimes used to prepare sites for planting, but their most effective use was found to be preparing sites for seeding, particularly in backlog areas carrying light brush and dense herbaceous growth. Rolling choppers found application in treating heavy brush but could be used only on stone-free soils. Finned drums were commonly used on jack pine–spruce cutovers on fresh brushy sites with a deep duff layer and heavy slash, and they needed to be teamed with a tractor pad unit to secure good distribution of the slash. The S.F.I. scarifier, after strengthening, had been "quite successful" for two years, promising trials were under way with the cone scarifier and barrel ring scarifier, and development had begun on a new flail scarifier for use on sites with shallow, rocky soils. Recognition of the need to become more effective and efficient in site preparation led the Ontario Department of Lands and Forests to adopt the policy of seeking and obtaining for field testing new equipment from Scandinavia and elsewhere that seemed to hold promise for Ontario conditions, primarily in the north. Thus, testing was begun of the Brackekultivator from Sweden and the Vako-Visko rotary furrower from Finland.

According to J. Charton and A. Peterson,<ref>{{cite journal |last1=Charton |first1=Jason |last2=Peterson |first2=Al |title=Motormanual Scarification: A Tool for Forest Restoration (Alaska) |journal=Ecological Restoration |date=2000 |volume=18 |issue=2 |page=131 |url=http://er.uwpress.org/content/18/2/131.1.extract}}</ref> motormanual scarification is best suited for small restoration projects (less than 25,000 trees) or in ecologically sensitive areas such as riparian zones or areas that are prone to erosion.

According to J. Charton,<ref>{{cite book |last1=Charton |first1=Jason |title=Scarification Intensity, Its Effect on First Year Survival and Growth of Machine Planted Spruce Seedlings |date=2001 |publisher=Alaska Pacific University |page=58 |url=https://books.google.com/books?id=zHAuOAAACAAJ}}</ref> scarification intensity can effect first year seedling mortality and growth.  Scarification should be properly applied to various site conditions to ensure that it works in a positive manner for planted seedlings.  Since both fireweed and bluejoint grass were shown as soil moisture moderators, reduced scarification intensity may be beneficial to planted seedlings in the wetter areas found on the Kenai Peninsula.  However, other factors such as encouraging natural regeneration to promote pre-beetle [[species composition]]s should be considered.  Reforestation managers should balance response to scarification in wet areas to achieve the proper balance between planted seedling survival and growth and achieving the desired level of natural regeneration.

===Mounding===

Site preparation treatments that create raised planting spots have commonly improved outplant performance on sites subject to low soil temperature and excess soil moisture. Mounding can certainly have a big influence on soil temperature. Draper et al. (1985),<ref name="drap">Draper, D.; Binder, W.; Fahlman, R.; Spittlehouse, D. 1985. Post-planting ecophysiology of Interior spruce. Interior Spruce Seedling Performance: State of the Art. Northern Silvic. Committee, Prince George BC. 18 p. (mimeo).</ref> for instance, documented this as well as the effect it had on root growth of outplants (Table 30).

The mounds warmed up quickest, and at soil depths of 0.5&nbsp;cm and 10&nbsp;cm averaged 10 and 7&nbsp;°C higher, respectively, than in the control. On sunny days, daytime surface temperature maxima on the mound and organic mat reached 25&nbsp;°C to 60&nbsp;°C, depending on soil wetness and shading. Mounds reached mean soil temperatures of 10&nbsp;°C at 10&nbsp;cm depth five days after planting, but the control did not reach that temperature until fifty-eight days after planting. During the first growing season, mounds had three times as many days with a mean soil temperature greater than 10&nbsp;°C than did the control microsites.

Draper et al.'s (1985)<ref name="drap" /> mounds received five times the amount of photosynthetically active radiation (PAR) summed over all sampled microsites throughout the first growing season; the control treatment consistently received about 14% of daily background PAR, while mounds received over 70%. By November, fall frosts had reduced shading, eliminating the differential. Quite apart from its effect on temperature, incident radiation is also important photosynthetically. The average control microsite was exposed to levels of light above the [[compensation point]] for only three hours, i.e., one-quarter of the daily light period, whereas mounds received light above the compensation point for eleven hours, i.e., 86% of the same daily period. Assuming that incident light in the 100-600 μE/m<sup>2</sup>/s intensity range is the most important for [[photosynthesis]], the mounds received over four times the total daily light energy that reached the control microsites.

===Orientation of linear site preparation, e.g., disk-trenching===

With linear site preparation, orientation is sometimes dictated by [[topography]] or other considerations, but where the orientation can be chosen, it can make a significant difference. A disk-trenching experiment in the Sub-boreal Spruce Zone in interior British Columbia investigated the effect on growth of young outplants ([[Pinus contorta|lodgepole pine]]) in 13 microsite planting positions: berm, hinge, and trench; in north, south, east, and west aspects, as well as in untreated locations between the furrows.<ref name="burt">Burton, P.; Bedford, L.; Goldstein, M.; Osberg, M. 2000. Effect of disk trench orientation and planting spot position on the ten-year performance of lodgepole pine. New For. 20:23–44.</ref> Tenth-year stem volumes of trees on south, east, and west-facing microsites were significantly greater than those of trees on north-facing and untreated microsites. However, planting spot selection was seen to be more important overall than trench orientation.

In a Minnesota study, the N–S strips accumulated more snow, but the snow melted faster than on E–W strips in the first year after felling.<ref name="clau">Clausen, J.C.; Mace, A.C., Jr. 1972. Accumulation and snowmelt on north–south versus east–west oriented clearcut strips. Univ. Minnesota, Coll. For., St. Paul MN, Minn. For. Res. Notes No. 34. 4 p.</ref> Snow-melt was faster on strips near the centre of the strip-felled area than on border strips adjoining the intact stand. The strips, 50 feet (15.24 m) wide, alternating with uncut strips 16 feet (4.88 m) wide, were felled in a ''Pinus resinosa'' stand, aged 90 to 100 years.

==See also==
{{Portal|Trees}}
{{div col|colwidth=22em}}
* [[Agroforestry]]
* [[Coppicing]]
* [[Dehesa]]
* [[Ecological thinning]]
* [[Forest dynamics]]
* [[Forestry]]
* [[Forest management]]
* [[History of the forest in Central Europe]]
* [[Hardwood timber production]]
* [[Live crown]]
* [[Natural landscape]]
* [[Permaculture]]
* [[Plantations]]
* [[Populiculture]]
* [[Seed tree]]
* [[Selection cutting]]
* [[Silvology]]
* [[Sustainable forest management]]
* [[World Forestry Congress]]
{{div col end}}

== References ==

=== Notes ===
{{reflist|colwidth=30em}}

=== Bibliography ===
{{refbegin|}}
* Daniel, T. W., J. A. Helms, and F. S. Baker 1979. ''Principles of Silviculture'', 2nd Edition. McGraw-Hill, New York. 521 pp.&nbsp;{{ISBN|0-07-015297-7}}
* Evans, J. 1984. ''Silviculture of Broadleaved Woodland''. Forestry Commission Bulletin 62. HMSO. London. 232 pp.&nbsp;{{ISBN|0-11-710154-0}}
* Hart, C. 1995. ''Alternative Silvicultural Systems to Clear Cutting in Britain: A Review''. Forestry Commission Bulletin 115. HMSO. London. 93 pp.&nbsp;{{ISBN|0-11-710334-9}}
* Nyland, R. D. 1996. ''Silviculture, Concepts and Applications''. The McGraw-Hill Companies, Inc. New York. 633 pp.&nbsp;{{ISBN|0-07-056999-1}}
* Savill, P., Evans, J., Auclair, D., Falck, J. 1997. ''Plantation Silviculture in Europe''. Oxford University Press, Oxford. 297 pp.&nbsp;{{ISBN|0-19-854909-1}}
* Smith, D. M. 1986. ''The Practice of Silviculture'', 8th edition. John Wiley & Sons, Inc., New York. 527 pp.&nbsp;{{ISBN|0-471-80020-1}}
* Smith, D. M., B. C. Larson, M. J. Kelty, P. M. S. Ashton. 1997. ''The Practice of Silviculture: Applied Forest Ecology'', 9th edition. John Wiley & Sons, New York. 560 pp.&nbsp;{{ISBN|0-471-10941-X}}
* Reid, R. (2006) 'Management of ''Acacia melanoxylon'' in Plantations' [https://web.archive.org/web/20070626125823/http://www.mtg.unimelb.edu.au/publications/Blackwood%20conference%20paper.pdf]
* Reid, R. (2002) 'The Principles and Practice of Pruning' [https://web.archive.org/web/20070626125838/http://www.mtg.unimelb.edu.au/publications/AFGLiftout%20no%202.pdf]
{{refend}}

==External links==
{{refbegin}}
* [http://www.ritchiewiki.com/wiki/index.php/Silviculture Silviculture] on the Ritchiewiki
* [http://www.na.fs.fed.us/spfo/pubs/silvics_manual/Table_of_contents.htm Silvics of North America Volumes 1 and 2 (USDA Forest Service, Agriculture Handbook 654, December 1990)] {{Webarchive|url=https://web.archive.org/web/20110708011138/http://www.na.fs.fed.us/spfo/pubs/silvics_manual/Table_of_contents.htm |date=2011-07-08 }}
* [http://forestry-dev.berkeley.edu/blodgett.php Blodgett Forest Research Station] {{Webarchive|url=https://web.archive.org/web/20131105093545/http://forestry-dev.berkeley.edu/blodgett.php |date=2013-11-05 }}
* [https://web.archive.org/web/20140912183121/http://nfdp.ccfm.org/silviculture/national_e.php Silviculture data in Canada since 1990]
* [http://nfdp.ccfm.org/terms/intro_e.php Silvicultural Terms in Canada] {{Webarchive|url=https://web.archive.org/web/20150507174146/http://nfdp.ccfm.org/terms/intro_e.php |date=2015-05-07 }}
{{refend}}

{{Forestry}}

{{Authority control}}

[[Category:Forest management]]
[[Category:Logging]]