Verification of Scaling Relationship Between Litter Production and Biomass in a Near Tropical Montane Cloud Forest

Litterfall plays a crucial role in the carbon and nutrient cycles of forest ecosystems. The amount of litterfall governs the amount of carbon and nutrient to be returned in a forest ecosystem. However, when it comes to quantify forest litterfall, collection of canopy characteristic parameters for existing litterfall models is usually time-consuming and labor-intensive. Recent studies indicated that, in metabolic scaling theory, there is a common relationship between terrestrial plant production and biomass; a major part of the production is contributed by litterfall. Therefore, there could be a relationship between litterfall and biomass, which could facilitate large spatial scale estimation of litterfall since biomass may be assessed using remote sensing. To investigate this relationship, we acquired monthly litterfall of a hinoki (Chamaecyparis spp.) dominant montane forest in the northeastern Taiwan (23.98 N, 120.97 E) across the elevation range of 1267-2080 m a.s.l. Monthly litterfall data were recorded from fifteen 0.09 ha plots and each plot consisted from four randomly arranged 0.5 m2 litterfall traps. In addition, diameter at breast height of each live hinoki trees (n = 1,129) within all plots were measured and total biomass was derived using an in-situ species-specific allometry. We found that the relationship between biomass and litterfall might depend on season. Significant concordance between the ranking of tree size and litter production of different sites (Spearman's rank correlation, rho = 0.60, p = 0.0001) could be found as the growing season started. With the aid of fine grain airborne light detection and ranging (LiDAR) data, we may be able to provide a spatial layer of hinoki biomass and map growing season litterfall over a vast region. Furthermore, the study could help increase our understanding of the mechanism governing the litter production and improve future prediction of the ecosystem function.