1 and 3D represent three-dimensional space, namely length, width and height. In forestry research, this can be used to describe the spatial distribution and structure of forests or trees. By measuring and analyzing the three-dimensional structure of forest, we can know the height, crown width and trunk diameter of trees, and then study the structure and function of forest ecosystem.

2, 5D means five-dimensional space, that is, three-dimensional space plus time dimension, that is to say, besides spatial distribution and structure, time changes are also considered. In forestry research, this can be used to study the dynamic change, growth process and succession process of forest ecosystem. Through long-term monitoring and measurement, we can understand the growth rate, species composition change and stand structure succession of forests.