森林群落无样地取样方法的改进

植物群落取样是植物群落学研究的重要基础，多年来已经形成了一些成熟的方法。该文在介绍传统无样地取样方法的基础上，综合中点四分法与最近邻体法提出了一种新的无样地取样方法——四分邻体法，并应用该方法对北京市门头沟区小龙门林场华北落叶松林进行了野外取样验证。研究结果表明:四分邻体法较为简单、可行，比原有方法（中点四分法）有更高的精度，应是一种较为有效且不增加野外调查工作量的方法。 

Improving the method of plotless sampling for forest community

Sampling for plant community is a basic work in the study of phytocoenology. A series of methods have been created and applied over the years. Based on an introduction of conventional methods of plotless sampling,the nearest neighbor method and point-centred quarter method were integrated to a new plotless sampling method-quartered neighbor method. Using the improved method,Larix principis-rupprechtii forest communities in Xiaolongmen Forest Station and Mentougou District of Beijing were investigated. The results indicate that the improving method (quartered neighbor method) is more precise than the old one (point-centred quarter method).It is obviously available and easy to use but requires no more workload than the old one.