In a lower montane cloud forest near Monteverde, Costa Rica, biomass, distribution and composition of epiphytes were assessed on trees of different size classes in an old-growth forest and in a nearby 30-year-old secondary forest. Information on forest structure was used to derive stand-level estimates of epiphyte biomass of 16.2 t/ha in the old-growth forest and 1 t/ha in the secondary forest. In the old-growth forest epiphytes were dominated by mosses, which, together with crown humus, made up 84% of the total epiphytic biomass. In the secondary forest mosses were the dominant epiphyte fraction (92%) and nearly no crown humus was found. Water contents of epiphytic mosses and crown humus were determined in situ using gravimetric methods. Minimum and maximum water content of mosses were 36% and 418% of dry weight, respectively. Crown humus showed less fluctuation in water content than did mosses, with minimum and maximum values of 92% and 356%, respectively. The maximum water storage capacities at the stand level were estimated at 4.4 mm (mosses) and 0.55 mm (crown humus) in the old-growth forest, and at 0.36 mm (mosses) in the secondary forest where water storage of crown humus could be neglected.
Epiphyte biomass and its hydrological properties in old-growth and secondary montane cloud forest, Monteverde, Costa Rica. Fog Interception for the Enhancing of Streamflow in Tropical Areas (FIESTA) Project Working Paper Series No. 1, Albrecht von Haller Institute for Plant Sciences, University of Göttingen, Göttingen, Germany, 17 pp.