[Litterfall in main forest ecosystems of Northeast China].

A three-year investigation on the litterfall of 15 forests in 4 different regions of Northeast China showed that the annual litterfall had a significant difference among forest types in the same region, but no significant difference was found between years. In the litterfall, leaf occupied 70% and more, while branch, flower and fruit were less than 20%. The branch production correlated positively with leaf production, and the correlation coefficient was 0. 82. According to the investigation of 5 forest types in Changbai Mountain, the litterfall was 2.62-9.14 times higher in autumn and winter than in spring and summer. The peak of leaf-fall appeared in autumn, while that of branch and others withered evenly during a year. The litterfall of same forest type decreased with increasing latitude, and the relationships of the total and birch litterfall with latitude were established. Both the total and the birch litterfall were positively related to annual mean temperature, with the correlation coefficient 0.95 and 0.91, respectively.