Tree Species Selection ProjectWestern larch (Lw) - Larix occidentalis Tree Species > Western larch Page Index Distribution Range and Amplitiudes Tolerances and Damaging Agents Silvical Characteristics Genetics and Notes External Links Other external information on Western larch Performance of Ponderosa Pine and Western Larch Planted North of Natural Ranges (pdf) BC Distribution of Western larch (Lw) Range of Western larch A two-storied western larch stand near Cranbrook. Two-storied, uneven-aged, western larch - western red cedar (this photo) and/or western hemlock mixtures are typical of the wetter portion of the IDF zone and the drier portion of the ICH zone. These climatic regions support the most productive growth in larch. top Geographic Range and Ecological Amplitudes DescriptionWestern 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 Ecological Amplitudes Climatic amplitude: (cool semiarid) - cool temperate - (subalpine boreal) Orographic amplitude: montane – (subalpine) Occurrence in biogeoclimatic zones: (lower southern ESSF), southern MS, (PP), southern IDF, southern drier ICH Edaphic Amplitude 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. top Tolerance and Damaging Agents Root System CharacteristicsWestern 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. Tolerancestolerance totolerance classcomments Low lightLA shade-intolerant and exposure-requiring species, except in the PP zone where it appears to be moderately shade-tolerant. FrostM HeatMInfrequent in the lower PP Water deficitMInfrequent on very dry sites. Water surplusLAbsent on waterlogged sites. Nutrient (mainly N) deficiencyMTolerates acid substrates. top Damaging Agentsdamaging agentresistance classcomments SnowHDue to open crown and deciduous nature WindHDeeply rooted with an open crown risk class FireHRisk is high but resistance to ground fires is also high; resistance increases with age. InsectMLarch casebearer, western spruce budworm, larch needle blight. FungiLNot a major concern; brown trunk rot, red ring rot. Other agentsMDwarf mistletoe (Arceuthobium laricis (Piper) St. John). Associated tree species and successional roleIn 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. associated tree speciesoccurance classmajor area of occurance Lodgepole pineHThroughout southern B.C. Common douglasMThroughout southeastern B.C. Western redcedarMSouthern ICH Subalpine firLSouthern B.C. Engelmann spruceLLower ESSF Ponderosa pineLUpper PP and lower IDF Western hemlockLSouthern ICH top Silvical Characteristicscharacteristicinterpretive classcomments Reproduction capacityHSeed production begins at <25 years; the northern population is a poor seed producer. Seed dissemination capacityMDispersion up to 250 m from the parent tree. Potential for natural regeneration in low lightLpractically nil; an shade-intolerant and exposure requiring species Potential for natural regeneration in the openHproviding the presence of exposed mineral soil or burnt forest floor; partial shade is beneficial for seedling establishment potential initial growth rate (<5 years)MLow (<5 cm/yr) in the establishment period, high (>50 cm/yr) thereafter. Response of advance regeneration to releasenaadvance regeneration does not develop in the absences of adequate light and seed-beds Self-pruning capacity in dense standsHbut dense stands are infrequent Crown spatial requirementsHWide, long crowns. Light conditions beneath closed-canopy, mature standsHassociates with well developed understory vegetation Potential productivityHThe most productive interior conifer; site index (50 yr @ bh) approaching 35 m on the most productive sites. LongevityHProbably even longer than 900 years - the reported maximum. top Genetics and Notes GeneticsSome population differences were detected but races, varieties, or subspecies of western larch are not known. NotesWestern 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. top