{{context, date=December 2014 A mixedwood stand is a

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

type in which 26% to 75% of the

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an ...

is made up of softwood trees.Natural Resources Canada, Canadian Forest Service. 1995. Silviculture terms in Canada (Terminologie de la sylviculture au Canada). NRCan, CFS, Ottawa, Ontario, 2nd edition. 109 p. Uncertainties of the definition, extent, and potential of mixedwood types necessitate the placement of some mensurational bounds on the subject of mixedwood management, especially the distribution and component sub-types, age classes, advance growth, productivity, and rotation ages. A major ecological factor in mixedwood management is the

spruce budworm ''Choristoneura'' is a genus of moths in the family Tortricidae. Several species are serious pests of conifers, such as spruce and are known as spruce budworms. Species *'' Choristoneura adumbratanus'' (Walsingham, 1900) *'' Choristoneura afri ...

; another is the problem of providing for sufficient white spruce regeneration.Project 07-24-0 analysis, Artificial regeneration of spruce in the spruce–fir forest type of Ontario. J.B. Scarratt, Canadian Forest Service, Ontario Region, Sault Ste Marie, Ontario. E3933 The white spruce–aspen mixedwood associations of the Prairie Provinces have a variety of compositions ranging from pure

aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the '' Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (Chin ...

to pure

white spruce White spruce is a common name for several species of spruce ('' Picea'') and may refer to: * ''Picea glauca'', native to most of Canada and Alaska with limited populations in the northeastern United States * '' Picea engelmannii'', native to the ...

, to mixtures of both.

Balsam poplar ''Populus balsamifera'', commonly called balsam poplar, bam, bamtree, eastern balsam-poplar, hackmatack, tacamahac poplar, tacamahaca, is a tree species in the balsam poplar species group in the poplar genus, ''Populus.'' The genus name ''Populu ...

white birch ''Betula papyrifera'' (paper birch, also known as (American) white birch and canoe birch) is a short-lived species of birch native to northern North America. Paper birch is named for the tree's thin white bark, which often peels in paper like ...

, black spruce,

balsam fir ''Abies balsamea'' or balsam fir is a North American fir, native to most of eastern and central Canada (Newfoundland west to central Alberta) and the northeastern United States (Minnesota east to Maine, and south in the Appalachian Mountains to ...

, and

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

s may also occur.Rowe, J.S 1972. Forest regions of Canada. Can. Dep. Environ., Can. For. Serv., Ottawa ON, Publ. 1300. 172 p. Silvicultural treatments have generally been aimed at promoting white spruce, primarily through plantation establishment and management. The type of stand of a given association is as much a product of successional stage and stand history McCune, B.; Allen, T.F..H. 1985. Will similar forests develop on similar sites? Can. J. Bot. 63:367–376. as it is of site type.Lieffers, V.J.; Beck, J.A. 1994. A semi-natural approach to mixedwood management in the prairie provinces. For. Chron. 70(3):260–264. Depending on seed source and seedbed conditions, recruitment of white spruce may begin relatively soon after disturbance or may be spread over many decades.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. Management of mixedwoods in the Prairie Provinces in the 1990s usually used clearcutting. When

is the main species to be regenerated, little treatment is applied to the site, but slash piles, compaction of soil, and damage to aspen root systems are minimized as much as is feasible in order to encourage suckering. In the coniferous harvest, aspen that is not harvested is usually left standing to reduce suckering, as well as for the benefit of wildlife. Regeneration of white spruce is more difficult. In general, plantation techniques are used, with mechanical site preparation following clearcutting. Depending on site conditions and availability of equipment, disk trenching, double disking, blading, ripper, or Marttiini plowing, Bracke spot scarification, high-speed mixing, or spot mounding are used. Plantings of white spruce have come to favour the use of large container or transplant stock. In the early years after clearcutting, site preparation and planting, shade-intolerant vegetation, such as aspen, ''Calamagrostis canadensis'', and

green alder ''Alnus alnobetula'' is a common tree widespread across much of Europe, Asia, and North America. Many sources refer to it as ''Alnus viridis'', the green alder, but botanically this is considered an illegitimate name synonymous with ''Alnus alno ...

compete strongly with the young outplants, frequently causing death.Lieffers, V.J.; MacDonald, S.E.; Hogg, E.H. 1993. Ecology of and control strategies for ''Calamagrostis canadensis'' in boreal forest sites. Can. J. For. Res. 23(10):2070–2077.

References

Taiga and boreal forests