The relationships between the distributions of forestlimit and subarctic coniferous trees and WI were examined in detail.
利用一些树种的分布资料，进一步论证了森林上限及亚寒带针叶林的分布与WI间的关系。
2
However, the externality of forest ecological effect makes its value cannot be compensated, which becomes principally limit factor for forest ecological construction.
但由于森林生态效益的外在性，使得其价值补偿无法实现，从而成为我国森林生态建设的根本性制约因素。
3
Due to the resolution limit of TM imagery, it is difficult to distinguish the forest variety in vertical structure.