Continuous litterfall was measured from 1993 to 2004 with litter-traps in a cool-temperate, broad-leaved deciduous forest at 1430 m in central Japan. The study site is located in Takayama Forest Research Station, on the middle slopes of Mt. Norikura (36°08’N, 137°25’E). A permanent plot of 1 ha (100m×100m) was set on a west-facing slope to study process-level flux measurements in 1998. Main dominant species in the permanent plot (ca. 50-60 yr olds) are Quercus and Betula. Litterfall was estimated from 14 litter traps (1m² area) settled on the permanent plot. Litterfall was separated into foliage (leaf litter) and woody material (branch, fruits, etc; branch ltter), oven-dried to constant mass, and weighed.

The average annual total of litterfall was 238±57 gC m^-2 (mean±SD) of which 70% were leaves. The year-to-year variation in total annual litterfall fluctuated markedly, the minimum being 184 gC m^-2 (in 2000) and maximum 394 gC m^-2 (in 2004). Inter-annual variavility of branch litter (70±60 gC m^-2, cv=85) were higher than those of leaf litter (170±18 gC m^-2, cv=11). The annual pattern of total, leaf and branch litter were most closely related to the air temperature before and at begining of the growing period (the mean temperature from April to June, T_AMJ). Unusually years, in 1998 and 2004, annual branch litter was over 3 times of other usually years.