Abstract: The purpose of the study is to explore the impact of crop tree release on the spatial structure of Pinus massoniana and broadleaf forests after the removal of pine wilt disease-infected trees, with the objective of optimizing forest structure, promoting forest growth, and enhancing broadleaf transformation to improve ecological functions. Eight 20 m × 20 m standard plots were set up, four-neighbor tree spatial structure units were used to calculate the uniform angle index, the mingling degree, layering index, openness, and Hegyi competition index, and the spatial structure before and after simulating crop tree release was compared. The results showed that after crop tree release, the average mingling degree of the eight plots increased from 0.604 to 0.668; changes in the uniform angle index of most plots indicated that tree distribution tended to be random; the average openness increased from 0.299 to 0.361, improving light conditions and growth space; the average layering index increased from 0.576 to 0.608, and the complexity of the vertical structure of trees in six plots increased; the average Hegyi competition index decreased from 0.875 to 0.751, relieving competition pressure among trees. Crop tree release strategies could significantly optimize the spatial structure of P. massoniana and broadleaf trees mixed forests, reduce competition pressure among trees, promote mingling degree and structural complexity, enhance species diversity, productivity, and stability of forests, and facilitate broadleaf transformation, thereby improving ecological functions.

Key words: crop tree release, mixed forests of Pinus massoniana and broadleaf trees, stand spatial structure