Shrub community development and annual productivity trends over a 100-year period on an industrial forest of Northern Idaho

Abstract

Understory community structure of conifer plantations and naturally regenerated stands on north and south aspects is assessed in stands up to 100 years following initial overstory removal on an industrial forest of northern Idaho. Industrial forests differ from other forests as they are managed for timber production, yet these forests maintain substantial wildlife populations and provide recreational opportunities. Species occurrence, stem density, twig density and height were compared between north and south aspects and between plantation and natural regeneration stands. Differences were detected relative to aspect and stand type but variation among sites was also significant. Annual shrub productivity, biomass of current year’s twigs, was estimated for all shrub species in 77 different stands. Productivity curves were developed for plantation and natural regeneration type stands on both north and south aspects which predict total stand annual productivity from time of initial cutting to over 100 years after overstory removal ( R 2>0.90). Maximum annual shrub productivity occurred between 7 and 14 years after overstory removal and broadcast burning. The findings of the study indicate that early successional stages across the landscape can, by forest management, be maintained to produce forage and influence animal distribution.