Spatial structure of mixed larch-spruce-fir stands.

To provide a referencing foundation for structural adjustments in a mixed larch（Larix olgensis）-spruce（Picea jezoensis）-fir（Abies nephrolepis） stand，found only in the over-logged forest of the Changbai Mountains，three parameters，namely uniform angle index，mingling index，and neighborhood comparison，were used to describe spatial structure. Results indicated that the stand uniform angle index was 0.520；the average stand mingling was 0.64；and for diameter at breast height with the neighborhood comparison，coniferous trees （esp. Picea jezoensis） dominated，with fewer Pinus koraiensis. The neighborhood pattern showed tree distribution was clustered，and the average mingling index indicated the stand was a medium mixed degree. Thus，these three spatial tests could be used to decide the trees and species to cut so as to adjust stands to an optimum structure.［Ch，3 tab. 17 ref.］