Commercial moss harvest in northwestern Oregon: biomass and accumulation of epiphytes Original Research Article

As concern over the sustainability of commercial moss harvest in the Pacific Northwest has grown, so too has the need to develop methods for estimating the rate of harvest, the biomass inventory, and the rate of accumulation of commercially harvestable epiphytes. We estimated biomass and net moss accumulation in 10 sites in both the historically heavily moss-harvested Coast Range and the historically relatively unharvested Cascade Range of northwestern Oregon. Harvestable epiphyte biomass in the lower canopy (<2 m above ground) ranged from c. 120 to 1470 kg ha−1 in the Coast Range, and 25 to 1068 kg ha−1 dry weight in the Cascade Range. The greater biomass at the Coast Range sites resulted from a higher density of suitable substrates, with epiphyte mass per unit area of substrate roughly equal in the two sets of sites. Epiphyte mass accumulation on vine maple Acer circinatum was extremely variable within and between sites, especially in the Coast Range. A model describing the factors affecting epiphyte mat accumulation is described. We recommend active management to conserve epiphytic bryophytes through promoting hardwood tree and shrub substrates, restricting moss harvest to the lower canopy, controlling the rate of harvest, and instigating rotation periods.