Estimation of epiphytic biomass and nutrient pools in the subtropical montane cloud forest in the Ailao Mountains, south-western China

Canopy organic matter (COM) composed of epiphyte community exists as a complex subsystem in the montane cloud forest (MCF). We estimated the biomass and nutrient pools of COM in a subtropical MCF in the Ailao Mountain National Nature Reserve (NNR). The diameter at breast height (DBH) of host trees was the best parameter in the estimation of epiphytic biomass, compared to the height (H) of host trees and the combination of both parameters. The effect of host tree species was negligible in the estimation. Therefore, it was concluded that the DBH data of all trees of a forest regardless of species was a suitable index for the non-destructive estimation of epiphytic biomass in field surveys, especially for investigations of larger study areas. According to species-specific equations, the total COM biomass was estimated to be 2,261 +/- A 537 (SD) kg ha(-1), which was dominated by bryophytes (73.6%) and canopy humus (13.9%). The greatest proportion of COM was located on the inner branches (52.2%), followed by outer branches, trunks, the understory, and branch junctions. The nutrient pools (mean +/- A SD, kg ha(-1)) of the COM were: N = 37.9 +/- A 9.0, P = 1.97 +/- A 0.47, K = 9.6 +/- A 2.3, Ca = 9.6 +/- A 2.3, Mg = 2.64 +/- A 0.63 and Na = 0.25 +/- A 0.06. Assessments of epiphytic biomass and nutrient capital supported the idea that the canopy subsystem holds a substantial pool of nutrients, especially when compared to the labile components of the forest ecosystem.