Abstract: Based on five forest management inventory data of Qingyuan county, Zhejiang province from 1985 to 2017, dynamic changes and causes of forest resources were analyzed combined with ecological, economic and social conditions. The results showed that the area of forest land decreased before 1989, and then increased, the area of forest and arbor continued to increase, while forest coverage first rose slowly and then rapidly, reaching 86.06% in 2017. The area of bamboo forest and the number of standing culm continued to increase. The total growing stock, arbor and unit area arbor growing stock decreased sharply before 1997 and then increased rapidly. The growing stock of young arbor forest continued to increase, that of near-mature, mature and over-mature arbor forest decreased before 1997 and then increased. The area and growing stock of artificial arbor forest and their ratio continued to increase, while growing stock natural forest decreased before 1997 and then increased. The proportion of area and growing stock of both forest tended to be the same. Analysis on causes of the changes demonstrated that “wood economy” and “mushroom economy” in the 1990s had great influence on the decrease of forest resources, while afforestation had effectively promoted the recovery of forest resources.