Abstract
Mass loss and nitrogen dynamics of decaying boles were evaluated in a Hinoki cypress plantation in Higashitsuno Village, Kochi Prefecture. Samples of boles with a diameter of 5 to 10cm thinned in 1994, 1998 and 2002 were collected and density and nitrogen contents in the samples were measured. The density of boles decaying for 0, 4 and 8 years was 436, 354, and 211kg/m^3 respectively. The decomposition constant determined from the exponential regression model was 0.091/yr and half time of disappearance was 7.6 years. Nitrogen content of boles decaying for 0, 4 and 8 years was 445, 434, and 423gN/m^3, and did not change significantly during the decomposition. We concluded that at the study site, nitrogen immobilization from the outer environment was insignificant, and microbes efficiently utilized the nitrogen inside the boles.
