Biological Cycling of the Nutrient Elements in Forest Ecosystems

Research results on the biological cycling of the nutrient elements in forest ecosystems were summarized, in which uptaking, returning and accumulating of nutrient elements were included. The general procedure of regulating nutrient cycling were also analysed and discussed in the paper. The rate of nutrient cycling changes with the forest types and geographical distribution. Generally, hardwood forests have higher cycling rate than coniferous forests, and those in low latitude zones have higher cycling rate than those in high latitude zones. The changes of forest productivity corresponds to the changes of nutrient cycling rates. Reallocation of nutrient elements within trees is a common phenomenon, and it is an adaptive reaction of the tree to malehabitat. Moreover, coniferous forests and those in high latitude zones have higher efficiency in nutrient use.