本文以张家口退耕还林工程的新造经济林为例,提出了一种利用高分辨率遥感技术监测新造林成活率及长势的方法。主要采用面向对象的信息提取技术提取退耕地新造林的树冠信息。开发了基于树冠分布图的树冠因子提取程序,计算树冠因子,统计造林成活率,从而掌握新造林地的现状。最后,根据实际测量的数据进行误差检验,由遥感数据自动提取的树冠冠幅平均误差为:东西冠幅为0.337m,南北冠幅为0.433m;计算新造林成活率的精度达到了89.837%。为退耕还林工程科学,高效的管理及决策支持提供了依据。

Successful forest resources monitoring requires an effective method to collect information related to forest area and tree crown.Current field-based assessment methodology provides the needed information,but is costly,and therefore assessment frequency is low.High-resolution remote sensing techniques provide a potentially low-cost alternative to field-based assessment.This paper proposed a method of monitoring survival rate and growth condition of economic forests in the farmland being returned to forests by using high resolution Quickbird imagery in Zhangjiakou,Hebei province.Multi-resolution image segmentation and object-oriented image analysis approaches were used for extracting farmland being returned to forests and tree crown information from Quickbird data.Firstly,tree crown classifictation was conducted using object-oriented image analysis,then,a program was developed to acquire tree crown factors and survival rate the classified from tree crown map.Finally,accuracy assessment was done according to field survey data,the results showed that the average error of tree crown size was as follows: 0.337m in east-west,0.433m in south-north,the accuracy of survival rate was 89.837%.The study provides a scientific basis for planning,management and decision support of the project of returning farmland to forests.