计划烧除对云南松纯林可燃物的影响

在云南省玉溪市新平县照壁山云南松纯林内，连续三年在同一位置设置固定样地，通过调查、采样，观测计划烧除时的点着时间、熄灭时间、辐射热、火焰高度、蔓延速度等火行为，调查并统计未计划烧除和计划烧除样地内的灌木和草本的物种组成、丰富度和频率。结果表明：随着计划烧除次数增加，灌木、草本以及蕨类的高度均降低，降低了林内的垂直连续性，即使发生火灾也很难导致树冠火的发生；经过三年连续的观测、调查，地表可燃物平均载量为 0.85±0.25 kg/m2，计划烧除的烧除效果与可燃物载量密切相关；短时间内，计划烧除样地内的灌木和草本的物种丰富度显著减少；计划烧除后紫茎泽兰重要值降低，蕨菜重要值明显增加。

Effects of prescribed burning on pinusyunnanensis pure forest fuel in Yunnan province

In the pure forest of pinus yunnanensis in Zhaobi moun?tain, Xinping County, Yuxi City, Yunnan Province, a fixed sample plot was set up at the same location for 3 consecutive years. Through field survey and sampling,the ignition time, extinction time, radiant heat, flame height, spread speed and other fire behaviors of prescribed burning were observed, and the species composition, richness and frequency of shrubs and herbs in the sample plots of unplanned and planned burning were investigated and counted. The results showed that: with the increase of planned burning times,the height of shrubs, herbs and ferns decreased, which reduced the vertical continuity in the forest,and it was difficult to cause canopy fire even if fire occurred. After 3 years of continuous observation and investigation,the average surface fuel load was 0.85 ± 0.25 kg/m2 ,and the burning effect of planned burning was closely related to fuel load. In a short period of time, the species richness of shrubs and herbs in the sample plot was significantly reduced. After planned burning, the important value of Eupatorium adenophorum Spreng decreased, while the important value of bracken increased significantly.