Objective The spatial distribution pattern of trees is important for evaluating whether the forest needs to be managed, and judging which distribution state (aggregated distribution, random distribution, or uniform distribution) of trees is a prerequisite for developing suitable management plans. Moderate and high severity forest fires can kill a large number of trees, and then change the distribution characteristics of stand diameter and the spatial distribution pattern of forest trees. We investigated natural Larix gmelinii forests in the Da’erbinhu National Forest Park, Inner Mongolia of northern China one year following a mixed-severity wildfire.
Method By comparing the distribution of stand diameter, the spatial distribution pattern of different types of trees and their association, we analyzed the influence of fire on the spatial distribution pattern of trees.
Result The results showed that in high severity areas, the number of small living trees and the gathering radius of small dead trees were relatively small. Compared with the unburned sample plots, the medium living trees presented a clustered distribution at the medium scale in the burned areas. The middle trees and the small trees were associated in the moderate severity burned sample plots. The medium dead trees and the surrounding small dead trees were positively associated within a radius of 4 to 8 m, while the medium living trees and the surrounding small dead trees were negatively associated within a radius of 8 to 20 m.
Conclusion The spatial pattern of trees and the association between trees of different sizes and different status are affected by the fire severity. Choosing suitable afforestation measures according to the aggregation scale of trees for different fire severities is of great significance to forest restoration after a fire. This study can provide a scientific basis for the protection and rational use of nature larch forests in the Great Xing’an Mountains of northeastern China.