北京密云森林资源评价与分析

以＂十五＂、＂十一五＂林业二类调查数据为基础,评价分析＂十一五＂期间北京市密云县森林资源现状与发展变化趋势,结果显示：密云县森林经营主要以防护型林种为主、经济林为辅,截止2009年,其森林覆盖率稳步增长至57.18%。大面积灌木林地、未成林地及宜林地经过良好抚育管理转化为有林地,且活立木总蓄积量增幅达21.71%,虽然存在林分结构不合理、纯林较多、幼龄林面积及蓄积量比重继续增大等问题,但森林单位面积蓄积量逐步增加。整体看来,密云县森林质量在不断提高,不健康林分比例逐渐降低,总体为一般健康水平。

Assessment and Analysis on Forest Resources in Miyun of Beijing

Based on the forest inventory data for management plan during 10th and 1 l th Five-Years Plan, the forest resources were assessed and analyzed in Miyun Country, Beijing. The results showed that：The forest management in Miyun country, gives top priority to protective forest, and the second management is economic forest, the forest coverage rate growth steadily to 57.18% by 2009. The large area of shrubland, ,land that should be planted trees later and have not been planted, was changed into woodland. , and timber stock vol- ume has been increasing 21.71%. Although there are many problems such as unreasonable forestry structure, large area of pure forest and the increasing acreage of young forest, however, per unit volume has gradually in- creased. Overall, the quality of the forest in Miyun County is constantly improving, which is standing for gen- eral health level.