<正>林分可视化系统Stand Visualization System，SVS是森林调查样地或小班水平可视化的理想工具软件，它生成的直观、立体图像，为林分生长和林业可视化的研究提供了新方法。笔者利用湿地松人工林林分调查数据，采用林分可视化系统展示了湿地松人工林林分可视化流程，详细介绍了该系统的使用方法和注意事项，并对SVS林分模拟结果进行了分析和讨论。

A comparative study on molecular detection of Bursaphelenchus xylophilus was conducted in this paper. Specific amplification PCR, ITS-PCR-RFLP and real time PCR were used in molecular detection of B. xylophilus. According to detection time, detection accuracy and operation skills, this paper summarized following conclusions: (1) Specific amplification PCR is used widely up to now because of its simple operation and low costs; (2) ITS-PCR-RFLP can be used to identify physiological race, being more accurate than Specific amplification PCR, however it takes long time to operate, it can be used for differentiation of population of B. xylophilus and species identification; (3) Real-time PCR takes short time to operate, has a high accurate results, and it’s easy to operate. However it needs specific instruments which are very expensive. It should be better used in quarantine of B. xylophilus.