Abstract:

The experiment was conducted in Laoshan Experimental Station of Maoershan Experimental Forest Farm, Northeast Forestry University. The results are as follows: The mass-loss rate of Mongolian Scots pine dead needles in the first and third year after falling are 34.67% and 63.75% respectively; the mass-loss ratio of dead cone, bark scales and branches in the first year after falling are 36.69%, 33.66% and 30.12% to that of dead needles respectively; and the mass-loss ratio of Korean pine dead needles and Mongolian oak, spring ulm and Manchurian ash dead leaves in the first and third year after falling are 58.70% and 84.71 %, 81.60% and 80.55 %, 134.94% and 156.55%, 124.26% and 147.71 % to that of dead needles of Mongolian Scots pine respectively. The mass-loss in the first year after falling is 26.61 % to total litter mass, in which 20.50% and 58.29% mass-loss are provided by broadleafed litter (its litter mass is 11.85% to total) and dead needles of Mongilian Scots pine (ite litter mass is 43.64 % to total); whereas only 10.92 %, 5.28% and 3.37 % mass-loss are provided by dead bark scales, branches and cones of Mongolian Scots pine (their litter mass is 24.28%, 13.10% and 6.89% to total respectively). The releasing ratio and amounts of nutrient elements in different litters varies seasonally. Generally speaking, the net releasing ratio of major nutrient elements (N, P, K, Ca, Mg, and Fe) in broadleafed litter is relatively high, whereas the releasing ratio of major and minor nutrient elements in litters of Mongolian Scots pine is relatively low. The net releasing ratio of K, Mg, N, Zn, Mn, P, Ca, Fe and Cu in first year after falling is 58.50%, 40.13%, 12.84%, 7.24%, 5.13%, 4.64%, 1.13%, -4.20% and -65.27% respectively. The-broadleaved litter (its litter mass is 11.85% to total) provided 44.58%, 54.92% and 80.40% net release of N, K and Mg respectively, as well as total net release of P and Ca.

Key words: Litters, Mass-loss, Nutriment elements, Decomposing dynamics, Net release