Fernandes P, Botelho H
Departamento Florestal, Centro de Estudos em Gestão de Ecossistemas, Universidade de Trás-os-Montes e Alto Douro, 5000-911 Vila Real, Portugal.
J Environ Manage. 2004 Jan;70(1):15-26. doi: 10.1016/j.jenvman.2003.10.001.
The ignition of low-intensity fires in the dormant season in the pine stands of north-western Portugal seeks to reduce the existing fuel hazard without compromising site quality. The purpose of this study is to characterise this practice and assess its effectiveness, based on information resulting from the normal monitoring process at the management level, and using operational guidelines, fire behaviour models and a newly developed method to classify prescribed fire severity. Although the region's humid climate strongly constrains the activity of prescribed fire, 87% of the fires analysed were undertaken under acceptable meteorological and fuel moisture conditions. In fact, most operations achieved satisfactory results. On average, prescribed fire reduces by 96% the potential intensity of a wildfire occurring under extreme weather conditions, but 36% of the treated sites would still require heavy fire fighting resources to suppress such fire, and 17% would still carry it in the tree canopy. Only 10% of the prescribed burns have an excessive impact on trees or the forest floor, while 89% (normal fire weather) or 59% (extreme fire weather) comply with both ecological integrity maintenance and wildfire protection needs. Improved planning and monitoring procedures are recommended in order to overcome the current deficiencies.
在葡萄牙西北部的松树林中,在休眠季节点燃低强度火灾旨在降低现有的燃料危险,同时不影响立地质量。本研究的目的是根据管理层面正常监测过程所获得的信息,利用操作指南、火灾行为模型以及一种新开发的规定火烧严重程度分类方法,对这种做法进行特征描述并评估其有效性。尽管该地区潮湿的气候严重限制了规定火烧的活动,但所分析的火灾中有87%是在可接受的气象和燃料湿度条件下进行的。事实上,大多数作业都取得了令人满意的结果。平均而言,规定火烧可将极端天气条件下发生的野火的潜在强度降低96%,但36%的处理过的地点仍需要大量灭火资源来扑灭此类火灾,17%的地点树冠仍会着火。只有10%的规定火烧对树木或林地有过度影响,而89%(正常火灾天气)或59%(极端火灾天气)的火烧既符合生态完整性维护需求,又满足野火防护需求。建议改进规划和监测程序,以克服当前的不足。