不同烈度林火对油松林潜在地表火行为的影响

油松是我国华北地区代表性树种之一，含有丰富油脂，容易引发大面积高烈度森林火灾。阐明不同烈度林火对油松林地表可燃物负荷量和潜在地表火行为的影响，对于油松林林火管理具有重要意义。以辽河源自然保护区2014年不同烈度林火干扰后油松林分为研究对象，根据不同烈度(重度、中度、轻度)和对照(未过火)分别设置3块20 m×20 m样地，共12块样地，调查地表可燃物和林分结构指标，结合室内实验，利用BehavePlus 5.0软件进行潜在火行为模拟，探讨不同烈度林火5年后油松林地表可燃物负荷量和潜在地表火行为特点，并分析影响潜在地表火行为的主要因素。研究结果表明：(1)不同烈度林火之间，细小可燃物负荷量和地表可燃物总负荷量均不存在显著性差异(P>0.05)。(2)不同烈度林火后，在不同风速和可燃物含水率条件下，油松林潜在地表火蔓延速度、火线强度不存在显著性差异(P>0.05),单位面积发热量、火焰高度、反应强度存在显著性差异(P<0.05)。(3)不同烈度林火后油松林潜在地表火行为主要受油松更新幼苗基径、灌木负荷量、油松平均冠幅、上层枯叶负荷量、油松更新幼苗密度的影响。研究结果表明不...

Effects of wildfire of different severities on potential surface fire behavior of Pinus tabuliformis forest

Pinus tabuliformis is one of the representative tree species in North China, which is rich in oil and easy to cause large area and high severity wildfire. It is of great significance for wildfire management of Pinus tabuliformis forest to elucidate the influence of wildfire of different severities on the surface fuel load and potential surface fire behavior of Pinus tabuliformis forest. In this study, Pinus tabuliformis forests with different severities of wildfire disturbance in Liaoheyuan Nature Reserve in 2014 were taken as the research object. According to different severities (high, moderate, low) and control (unburned), three 20 m×20 m sample plots were set, and a total of 12 plots were set. Based on the investigation of surface fuel and stand structure index, combined with indoor experiments, the potential fire behavior was simulated by BehavePlus 5.0 software. The characteristics of surface fuel load and potential surface fire behavior of Pinus tabuliformis forest after 5 years of fire with different severities were discussed, and the main factors affecting the potential surface fire behavior were analyzed. The results indicated that (1) there was no significant difference in the fine fuel load and the total surface fuel load between different severities wildfire disturbance (P>0.05). (2) Under the conditions of different wind speeds and fuel moisture content, there were no significant differences in the potential surface fire spread rate and fireline intensity (P>0.05), but there were significant differences in the calorific value per unit area, flame height and reaction intensity (P<0.05) after forest fire disturbance with different severities. (3) The potential surface fire behavior of Pinus tabuliformis forest with different severities was mainly affected by the regeneration seedling base diameter of Pinus tabuliformis, shrub load, average canopy width of Pinus tabuliformis, load of upper dead leaves, and the regeneration seedling density of Pinus tabuliformis. The results showed that forest fires with different severities could reduce the severity and risk of reburning.