The community not only has layers on the ground, but also has root distribution underground. Underground and overground communities generally correspond; Tree roots extend into the deepest soil, shrub roots are shallow, herbaceous roots are mostly concentrated in the surface soil, and moss roots are directly distributed on the surface.

The vertical stratification of biological communities is closely related to light conditions, and the plants in each layer adapt to the light level of that layer and reduce the light intensity of the lower layer. The decline of light intensity is the most obvious phenomenon in the forest. The tallest tree has plenty of light. On average, the light reaching the lower tree is only 10 ~ 50% of the total light of the upper tree, 5 ~ 10% of the shrub layer and 1 ~ 5% of the herb layer. With the change of light intensity, the temperature and air humidity also change.