The Idaho Forestry Program: Providing Opportunities for Forest Management While Meeting Riparian Conservation Objectives

The Idaho Forestry Program (IFP) is a proposed program that if adopted would apply to forest management and timber harvest on state and private lands in the Salmon and Clearwater Basins in Idaho.  ESA-protected species addressed under the IFP include spring/summer Chinook salmon, fall Chinook salmon, sockeye salmon, steelhead and bull trout. Under the IFP, streamside management zones could be actively managed using a 25 ft no harvest zone and commercial thinning within an outer 50 ft buffer.  To evaluate the effects of the IFP on ESA-protected species, we adapted existing models for simulating large woody debris recruitment (LWD) and effective shade (shade) for forest and stream conditions in central Idaho.  We compared LWD and shade inputs produced by the IFP to that produced by unharvested stands.  We also compared IFP results to LWD and shade produced by thinning the entire 75 ft buffer; this was a meaningful comparison for Idaho Forest Practices rule-making.  We informed our models using riparian inventories along 119 fish-bearing streams crossing primary forest lands managed by the Idaho Department of Lands.  Simulation results demonstrate that forest management activities conducted under the IFP would lead to a reduction in LWD and shade of about 10% compared to that provided if stands were not harvested.   Stands harvested under the IFP would produce levels of LWD and shade similar to that produced by a 75 ft buffer thinned to a relative density of 65%; however, the IFP permits harvest of 10% more volume than could be achieved by uniformly thinning the 75-ft buffer to that residual stocking.  Overall, we found that by maintaining a 25-ft no harvest zone, the IFP increased opportunities to conduct economic timber harvest within stream management zones while maintaining stand conditions protective of ESA species.