2017 Volume 59 Issue 1 Pages 13-25
Non-commercial thinning is known to produce aerial needle litter. The vertical position of litter mass is important for understanding material cycling in thinned forests because aerial litter decomposes more slowly than ground litter. The decomposition processes of aerial and ground litter and the physical falling of aerial litter to the ground determine the dynamics of remaining amount and vertical distribution of litter. Furthermore, decomposition in each position and aerial litter fall may depend on meteorological factors. We aimed to estimate the dynamics of remaining amount of litter by linking litter fall and decomposition rates and developed Bayesian models to clarify the effects of meteorological factors on these processes. We monitored decomposition and aerial litter fall of a Cryptomeria japonica needle litter for 42 months after thinning. The model results suggested that temperature was a determining factor for temporal variation in the litter decomposition rates, while precipitation was the main determining factor for temporal variation in the fall rate of aerial litter. Temperature and precipitation were positively correlated with decomposition and aerial litter fall, respectively. Our linked model suggested that aerial litter fall contributed only slightly to remaining amount of total litter during the 42 months after thinning, but affected the vertical distribution of litter considerably. The model also indicated that the above meteorological factors contribute notably to the dynamics of remaining amount of total litter and the vertical distribution. These results suggest that our model has the potential to be an effective tool for understanding material cycling in non-commercially thinned stands in temperate regions.