Characteristics of old-growth Douglas-fir forests

Old-growth forests in the Douglas-firregion are distinguished primarily byseveral structural characteristicsincluding a wide range of tree sizes andages, a deep multilayered crown canopy,large individual trees, and accumulationsof coarse woody debris including snags anddown logs of large dimension. Old-growthforests are compositionally diverse andinclude many species for which it isoptimum habitat. Old-growth forests areproductive although the bulk of the energyis used for respiration. Woodaccumulations tend to be stable with growthat least balancing mortality. Nutrientlosses and erosion are generally low inold-growth watersheds. The large trees,snags, and logs are the key structuralfeatures of old-growth; silviculturalistscan use these as critical elements indeveloping and applying managementschemes.