中国天然林保护工程区森林覆盖遥感监测

天然林资源保护工程（天保工程）自1998年开始实施至2020年底结束，标志着我国林业由以木材生产为主向以生态建设为主进行转变，对天然林资源开展定量监测与评估，有助于全面、及时、科学地评价天保工程对森林资源的保护成效。基于公开发布的土地覆盖产品，利用新的遥感数据合成算法构建了森林类型综合提升方法，生产了一套我国天保工程区的森林覆盖产品，对天保工程区1997年至2020年间的森林覆盖情况开展监测与评估。利用中国森林生态系统定位研究网络数据（CFERN）、森林资源规划设计调查数据和地面调查数据进行精度检验，森林类型的分类精度优于90%。分析结果显示，自天保工程实施以来，工程区的森林覆盖度总体呈恢复性增长趋势，森林覆盖从1997年的30.15%增长到2020年的31.74%，净增长1.59%，其中，长江上游地区森林增长量最高，占全工程区森林增长面积的50.97%。研究结果表明我国天保工程区内森林资源得到有效保护和恢复，天保工程实施效果显著。

Forest coverage monitoring in the Natural Forest Protection Project area of China

The Natural Forest Protection Project (NFPP) has been implemented since 1998 and completed by the end of 2020, which marked the transformation of China''s forestry from wood production to ecological construction. Quantitative monitoring and assessing of natural forest resources is helpful to evaluate the effect of natural NFPP comprehensively, timely and scientifically. Based on the public land cover products, this paper uses new remote sensing data composition algorithm and the forest type comprehensive promotion method to produce a set of land cover products aiming at the forest coverage of the NFPP areas in China. The forest cover for NFPP is monitored and evaluated from 1997 to 2020. The classification accuracy of land cover products for NFPP is verified by the field data of the Chinese Forest Ecosystem Research Network (CFERN), forest inventory and planning data and ground survey data, which indicate the forest accuracies more than 90%. The results show that the forest coverage presents a general trend of recovery growth since the beginning of the NFPP. The forest coverage changes from 30.15% in 1997 to 31.74% in 2020, with a net increase of 1.59%, of which, the forest growth in the upper reaches of the Yangtze River is the highest, accounting for 50.97% of the total forest growth areas. The results show that the forest resources in the NFPP area are effectively protected and restored, and the implementation effect of the project is significant.