从预防树冠火角度确定云南松的最低修枝高度

Determination of the Lowest Pruning Height of Pinus yunnaneneis Trees from the Aspect of Preventing Crown Fire

为确定可以阻止云南松林地表火向树冠火转化的最低修枝高度,测定云南松针叶的着火点,在自行设计的燃烧床上对不同载量的云南松林细小可燃物进行6次燃烧试验,通过分析可燃物地表火过程中燃烧区域垂直方向上的温度变化,将燃烧区域垂直方向上最高温度等于着火点处的高度确定为云南松的最低安全修枝高度。经推算,可燃物载量为2.32 kg/m2、2.44 kg/m2、2.61 kg/m2、3.19 kg/m2、3.77 kg/m2、4.06 kg/m2时,云南松的最低安全修枝高度分别为0.83 m、1.14 m、1.21 m、1.51 m、1.62 m、1.86 m。

Abstract：In order to determine the lowest pruning height of Pinus yunnaneneis trees which could prevent forest crown fire conversion from surface fire, combustion experimentations of fine fuel were tested 6 times with experimental equipment designed by the authors and the ignition temperature were measured. The lowest prun- ing height of Pinus yunnaneneis trees from the aspect of preventing crown fire, at which the highest temperature of the height in combustion field equaled ignition temperature, was put forward based on temperature curves of different heights on combustion field in experimental course. The results showed that the respectively lowest pruning heights of Pinus yunnaneneis trees were 0. 83 m, 1.14 m, 1.21 m, 1.51 m, 1.62 m, 1.86 m while forest fuel loads were 2.32 kg/m^2, 2.44 kg/m^2, 2.61 kg/m^2, 3.19 kg/m^2 ,3.77 kg/m^2, 4.06 kg/m^2.