Using inventory projections to evaluate management options for the nontimber forest product of epiphytic moss

Several US national forests have implemented moratoria on harvesting moss in the absence of management plans that can demonstrate long-term sustainability. To fill this gap, harvest schedules are presented for epiphytic moss in northwestern Oregon based on a variation of the classic volume control model. Commercial moss inventory over a 150-year simulation period was estimated as initial inventory plus biomass increment minus mortality and legal harvest. A 50-year exclusion period between harvests was chosen based on the minimum time estimated to replenish moss and to maintain acceptable species richness for the moss and the invertebrate taxa that inhabit it. Mean estimates for the input parameters were used for a "baseline" scenario and the upper and lower 95th percentile confidence intervals for the estimates were used for "optimistic" and "conservative" scenarios describing moss growth and yield estimates. Recent moss harvest permit levels exceed those that would sustain resource yield and biodiversity even under the optimistic scenario. Avoiding resource depletion would require reducing permit levels by 3.5- and 1.4-fold under baseline and optimistic scenarios, respectively. Sustained yield would require reductions of 6.8- and 1.7-fold, respectively.