Western larch (Lw) - Larix occidentalis
Western larch is a medium - to large-sized (occasionally >60 m tall), deciduous conifer, with a branch-free stem over much of its length; short, narrow, pyramidal crown and horizontal branches; reddish-brown, deeply furrowed bark with flaky ridges. Western larch is the world’s largest and most important timber species of this genus. It is an aesthetically attractive species, which is used for lumber, fine veneer, poles, ties, mine timber, and pulp.
|Geographic Range||Geographic element:
Western North American/Cordilleran
Distribution in Western North America:
central in the Cordilleran region
(cool semiarid) - cool temperate - (subalpine boreal)
montane – (subalpine)
Occurrence in biogeoclimatic zones:
(lower southern ESSF), southern MS, (PP), southern IDF, southern drier ICH
Range of soil moisture regimes:
(very dry) - moderately dry - slightly dry - fresh – moist - (very moist)
Range of soil nutrient regimes:
(very poor) - poor - medium - rich - very rich
In comparison with interior common douglas, western larch is infrequent on moist and very moist sites on which common douglas attains the most productive growth. It appears that western larch is more abundant and vigorous on calcium- and magnesium-rich soils than on acidic soils.
|Root System Characteristics||Western larch develops a deep and extensive root system. Fibrous roots under young larch stands extend up to 100 cm in depth. Wind-fallen mature larch trees have their roots usually infected by root rots. Roots of western larch are associated with both ecto- and endo-mycorrhizae.|
|Associated tree species and successional role||In southeastern British Columbia, western larch may grow in pure stands but more frequently, it grows in mixed-species stands. Old-growth western larch stands are rare. It is present in early, mid-, and late stages of fire-driven, secondary succession.|
|Genetics||Some population differences were detected but races, varieties, or subspecies of western larch are not known.|
|Notes||Western larch forests are valued for their multiple resource values. Thus, the presence of the species in pure as well as mixed-species stands should be maintained or even increased where multiple resource use is the major management objective. More detailed silvics information is given by:
Schmidt, W.C. and R.C. Shearer. 1990. Larix occidentalis. Pp. 160-172 in R.M. Burns and B.H. Honkala (technical coordinators) Silvics of North America, Vol. 1. Agri. Handbook 654, USDA For. Serv., Washington, D.C.
Schmidt, W.C. and K.J. McDonald. (compilers) 1992. Ecology and management of Larix forests. GTR-INT-319, USDA For. Serv., Intermountain Research Station, Ogden, Utah.
Schmidt, W.C. and K. J. McDonald (compilers) 1995. Ecology and management of Larix forests: a look ahead. Proceedings of an International Symposium, Whitefish, Montana, October, 5-9, 1992. GTR-INT-319, USDA For. Serv., Intermountain Research Station, Ogden, Utah.