Moss harvest: What's out there and how fast does it grow?

As the harvest of moss as a secondary forest product grows, so too, does the need to understand better the ecology of the species involved. Biomass, species composition, and biomass accumulation rates were measured for epiphytic moss mats on hardwood trunks in ten sites within the Hebo District of the Siuslaw National Forest in Oregon's Coast Range (Tillamook County). Sites ranged from 400 to 1350 m in elevation with mixed or coniferous overstories of 65 to 110 years in age. Mats were weighed to estimate the biomass of "harvestable mosses" (mosses and hepatics) at each site. Harvestable quantities ranged from 120 to 3050 kg/ha, dry weight. A total of 23 bryophyte, 10 lichen, and 2 vascular species were present in the mats. Five of these are Record of Decision Strategy (ROD) 4 listed species. Hardwood stems were aged by coring and accumulation rates were estimated from plots of biomass vs. stem age. Biomass accumulation rates of mats were estimated to be approximately 5.1 g/m/yr averaged over the first 15 years of vine maple growth, 2.9 g/m/yr averaged over the next 25 years, and -0.5 g/m/yr on average thereafter. Slow rates of accumulation and the inadvertant harvest of nontarget species (e.g., ROD listed lichens) provide the incentive to manage the harvest of moss as a secondary forest product more actively than in the past.