树冠是树木获取光能并进行能量转换的主要场所,在监测树木长势,估算树木生物量等方面具有重要作用。及时准确获取树冠参数信息有助于研究树木生长状况和森林变化动态,有效改善森林经营管理。无人机遥感具有快速机动、云下飞行、影像分辨率高、成本低等优势,非常适合于亚高山针叶林树冠遥感影像的获取。论文以贡嘎山雅家埂局部范围亚高山针叶林为研究对象,采用固定翼无人机获取可见光遥感影像,基于面向对象方法自动提取了亚高山针叶林的东西冠幅、南北冠幅、单元面积树木数和郁闭度等参数。以目视解译结果作为参考数据进行验证,东西冠幅和南北冠幅的提取精度分别是0.765 1和0.855 6,单元面积树木数和郁闭度的提取精度分别是0.99和0.92。研究结果表明,基于无人机遥感影像的树冠参数信息自动提取方法高效可靠,能够满足亚高山针叶林生长状况快速评价与动态遥感监测的需求。

As the main part for trees to obtain light energy and convert energy,crown plays an important role in monitoring tree growth,estimating tree biomass and so on.Timely and accurate acquisition of crown parameter information can help to study tree growth status and forest dynamic changes,and improve forest management effectively.With superiorities of low cost,safety,flexible take-off and landing,ability to fly under cloud,hyper spatial image resolution,UAV (Unmanned Aerial Vehicle) remote sensing is very suitable for obtaining remote sensing imagery of crown of subalpine coniferous forest.We extracted tree crowns and crown parameters such as the transmeridional crown,north-south crown,number of trees per unit area,and density of subalpine coniferous forest in one region of Sichuan Gongga Mountains from fixed-wing UAV images based on object-based image analysis method.The visual interpretation result was taken as reference data to verify the precision.The results showed that extraction accuracies of transmeridional crown,north-south crown,number of trees per unit area,density were 0.77,0.86,0.99 and 0.92 respectively.This result indicated high effectiveness and reliability of forest crown information automatic extraction based on optical UAV remote imagery,and UAV remote sensing can meet the demands of evaluating subalpine coniferous forest growth status and monitoring dynamic changes.