摘要
广西三门江森林公园的松栎异龄林有着大量的地表可燃物和梯状可燃物,树冠呈连续分布,易发生树冠火。设计了5种方案来处理该区域5个样地的可燃物。处理Ⅰ、Ⅱ、Ⅲ主要是砍除灌木和修剪小树,提升冠基高;处理Ⅳ除砍灌之外,去除了2/3的1、10h时滞可燃物;处理Ⅴ为处理Ⅰ+处理Ⅳ。针对桂中地区的气候和物候特点,设置了低、中、高3种燃烧条件。利用FCCS计算各种处理的火行为参数,参照Van Wagner树冠火模型,分析可燃物处理前后可能发生的林火的类型、强度,比较了几种可燃物处理方案在减少树冠火风险上的有效性。结果表明,就减少树冠火发生的有效性而言,处理Ⅴ>处理Ⅳ>处理Ⅲ>处理Ⅱ>处理Ⅰ。在低燃烧条件下,4种可燃物处理方案都可以将火行为降减为地表火。随着燃烧条件的提高,可燃物处理有效性下降。在高燃烧条件下,虽然可燃物处理可以降低火强度,但是,5种可燃物处理方案都不能避免树冠火的发生。
Pine-Fagus forest in Sanmenjiang forest park was characterized by continuous canopy and abundant surface and ladder fuels accumulated over years lacking silvicultural management, vulnerable to crown fire. Five fuel treatments were designed to mitigate crown fire hazard of the forest, with treatment Ⅰ, Ⅱ, Ⅲ mainly clearing shrubs and pruning young trees to increase height to live crown; treatment Ⅳ clearing shrubs and removing 2/3 1h and 10 h timelag fuels; treatment Ⅴ was a combination of treatment Ⅰ and Ⅳ. Considering climatic and phenological characteristics of Central Guangxi, 3 combustion scenarios were set up to represent low, moderate and severe environmental conditions. Fuel Characteristic Classification System（FCCS） was used to calculate fire behavior of the treatments. Combined with Van Wagner（1977） crown fire model, fire type, fireline intensity of each sampled plots were analyzed, and effectiveness of fuel treatments in mitigating crown fire hazard was compared. The results showed that in terms of effectiveness in mitigating crown fire hazard, treatment ⅤⅣⅢⅡⅠ. Under the condition of low combustion, 4 treatments could reduce fire behavior to surface fire. The effectiveness of fuel treatments decreased as combustibility increased; and under severe combustion condition, though the fuel treatments could cut fire intensity, none of the treatments designed could prevent the stands from crown fire.
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2016年第3期46-52,共7页
Journal of Central South University of Forestry & Technology
基金
国家林业公益性行业科研专项(201204512)
广西科技厅项目(桂科攻14124004-3-11)
关键词
树冠火
可燃物处理
FCCS
火线强度
含水率
crown fire
fuel treatment
FCCS
fireline intensity
moisture scenario
