Abstract: By dissecting living trees in mountain forests, the spatial distribution characteristics of the population of Monochamus alternatus Hope within the wood segments of Pinus massoniana Lamb. were analyzed. Meanwhile, the emergence of Monochamus alternatus Hope was monitored at different altitude sites in mountain forests to explore its population dynamic patterns. The results showed that in the three plots at different altitudes of 450 m (D1), 680 m (D2) and 1 000 m (D3), the density of intrusion holes and emergence holes of Monochamus alternatus Hope was relatively high in the middle - upper part of the trees. The correlation equations established for the number of intrusion holes, emergence holes and the height of the tree trunks in the three altitude plots could effectively estimate the population distribution of Monochamus alternatus Hope within the trees. In the altitude plots of D1 and D3, the number of intrusion holes was significantly correlated with the number of emergence holes, with correlation coefficients of 0.812 and 0.674, respectively. At an altitude range of 450~1 000 m, both the initial emergence period and the final emergence period of Monochamus alternatus Hope were gradually delayed as the altitude increased. The initial emergence period was postponed by 15~30 d, and the final emergence period was postponed by 16~31 d. Its emergence period lasted for 86~88 d. Its active period was also delayed as the altitude increased. The initial appearance of its activity was postponed by 15~25 d, but the final appearance of its activity was consistently in the first ten-day period of October.

Key words: Pinus massoniana Lamb., living wood, Monochamus alternatus Hope, population distribution, alpine forest area, dynamic characteristics