Foliage loss due to snow, wind, and winter drying damage: its effects on leaf biomass of some western conifer forests

Abstract

Damage to forest canopies by wind, snow, or winter desiccation significantly reduced stand leaf biomass and area below "steady-state" levels in several western coniferous forests. Leaf biomass of 12 different western conifer forests sampled for an average of 4 years was reduced by as much as 36.3, 34.5, and 42.2% by single wind damage, snow breakage, or winter desiccation events, respectively, during the sampling interval. Foliage loss exceeded annual foliage production as estimated from leaf litterfall in about half the stands where damage occurred. Production efficiency (Mg dry matter•ha−1•year−1•Mg−1 foliage) by remaining foliage appeared to increase after damage. Based on the data available, major canopy damage appears to occur at roughly 9- to 16-year intervals in western coniferous forests. However, this canopy damage is epidosic and unpredictable. Such damage adds an additional measure of uncertainty to forest productivity models.