To predict response of leaf litter decomposition to climate changes, we conducted litter-bag decomposition experiment along an elevation gradient in Hakkoda, northern Japan for 3 years. In this area, we set 2 permanent plots every 200m from 400 to 1400m a.s.l. Leaf litter of beech (Fagus crenata) and fir (Abies mariesii), which are dominant species in lower (400-900m) and higher elevation (900-1400 m), respectively, were decomposed in each plot where the litter was collected. In addition, common leaf litter of each species was decomposed in all plots.

The decomposition rates were evaluated based on time and on temperature during the experiment. Generally, the rates per unit time were not different between beech and fir forests, although they differed significantly among plots within each forest type. In contrast, the rates per unit soil temperature were higher in fir forests than in beech forests, even when the common fir litter was decomposed in both forests. Thus, the decomposition rate in higher elevation can be more sensitive to future warning than that in lower elevation.