森林资源监测是国情国力调查的重要组成部分,是林业重要的基础性工作。遥感技术弥补了传统人工抽样调查的不足,然而遥感样地的布设方式、数量及遥感判读精度是宏观森林资源监测值得关注的问题。本研究在西藏自治区2015年森林资源宏观监测成果的基础上,采用不同群团抽样方案与遥感判读相结合的方式,得出全区森林覆盖率,并分析群团内样本数量变动对西藏森林资源宏观监测结果的影响。研究结果表明,当样地内群团数量达到25个时,估计均值与实际森林覆盖率相差最小,变动系数最稳定,抽样精度达到最高94.49%。由此可知,大样地群团抽样方法对森林资源宏观监测来说是一种可行高效的方法,且工作量显著低于图斑区划判读的工作量。

Forest resource monitoring is a basic work of forestry,which is an important part of national investigation.The field observation method to monitor macro-forest resource is time-consuming,labor-intensive and costly.Remote sensing technology provides a practical solution to accurately monitor macro-forest resource.However,sample design,sample size and remote sensing interpretation accuracy have attracted wide publicity in macro-forest resource monitoring.In this paper,cluster sampling and remote sensing visual interpretation methods were applied to estimate forest coverage rate of Tibet.At the same time,the impact of size variation in cluster sampling was analyzed using forest resources macro monitoring in Tibet 2015.The results showed that the sampling accuracy reached the highest 94.49% when the number of sample sizes of each sample plot increased to 25.There was no significant difference between estimated result and actual forest coverage,and the coefficient of variation was stable.Therefore,the cluster sampling method was a feasible and efficient method,and the workload was significantly lower than that of visual interpretation method.