作 者:
王秋华;李晓娜;叶彪;龙腾腾;闫想想;李世友;董入云
单 位:
云南森林自然中心;西南林业大学土木工程学院云南省森林灾害预警与控制重点实验室;西南林业大学地理与生态旅游学院
关键词:
森林火灾;火焰高度;辐射热;火强度;潜在火行为;华山松;昆明
摘 要:
在实验室内模拟近似无风状态下华山松纯林地表可燃物的燃烧火行为,掌握潜在火行为相关特征,为安全扑救、避免人员伤亡提供参考依据。在昆明周边的云南森林自然中心华山松纯林内设置样地,通过外业调查、采样,在实验室燃烧床内模拟火行为,包括引燃时间、熄灭时间、辐射热、火焰高度、蔓延速率等,并计算火强度。华山松纯林地表可燃物的潜在火行为:点烧的可燃物含水率为5.71%~18.79%,接近野外的8.99%~14.96%,都很干燥、极易引燃;上坡火和下坡火的引燃时间很短,仅为1~2 s,遇到火源就被引燃,产生明亮火焰;下坡火的最大平均火焰高度达56.4 cm,明显高于上坡火的26.8 cm,前者的平均火焰温度最高为530℃,后者不到450℃;上坡火和下坡火的平均热辐射((4.1±0.9)~(7.2±1.0) kW/m~2和(4.2±0.7)~(6.9±1.0) kW/m~2)、蔓延速率(0.14~0.35 m/min和0.12~0.26 m/min)、烧损率(23.81%~51.40%和22.79%~58.33%)以及火强度(102.4~293.7 kW/m和116.0~322.9 kW/m),差距不明显。华山松纯林地表可燃物潜在燃烧火行为是低强度火,小坡度燃烧特征明显:燃烧相对稳定、平缓、火蔓延慢,火焰高度和火强度较小。但在野外,、地表可燃物里有部分半分解、分解的树桩和大枝条,一旦着火,即使地表明火扑灭,在适宜条件下,也能死灰复燃,危险性高。
译 名:
Potential fire behaviors of ground fuels in pure forest of Pinus armandii Franch
作 者:
WANG Qiuhua;LI Xiaona;YE Biao;LONG Tengteng;YAN Xiangxiang;LI Shiyou;DONG Ruyun;School of Civil Engineering,Southwest Forestry University,Yunnan Key Laboratory of Forest Disaster Warning and Control;School of G eography and Eco-toursim,Southwest Forestry University;Yunnan Natural Centre of Forestry;
关键词:
forest fire;;flame height;;radiation heat;;fire intensity;;potential fire behaviors;;Pinus armandii Franch;;Kunming
摘 要:
By examining fire behaviors of ground fuel in pure forest of Pinus armandii Franch in an approximately calm state in the laboratory,the features of fire behavior were investigated. The objectives of this research were to provide references for fire fighting,to put forward better counter measures for securely fire fighting,to avoid casualties,and to effectively prevent forest fires. After selecting typical plots of pure forest of Pinus armandii Franch,which placed in Nature Forestry Centre of Yunnan Province located on suburb of Kunming city. Forest fields were surveyed,samples were collected in the fields,and fire behaviors were investigated in the laboratory,which included the ignite time,extinguish time,radiation heat,and flame height and temperature,at the same time,the fire intensity was calculated.The results showed that ground fuels in pure forest of Pinus armandii Franch were in dry condition,such as the moisture contents of fuels before igniting were 5.71%-18.79%,while,moisture contents of field samples were 8.99%-14.96%,both were too dry to be ignited quickly,and their igniting time was one to two seconds. The average flame height of downhill fire was 56.4 cm,which was higher than the average flame height of 26.8 cm for upslope.The average flame temperatures of downhill and upslope were 530 ℃ and 450 ℃,respectively. The average heat radiation,spread speed,rate of fire loss and fire intensity of upslope and downhill fire were( 4.1±0.9)-( 7.2±1.0) kW/m~2 and( 4.2±0.7)-( 6.9±1.0) kW/m~2,0.14-0.35 m/min and 0.12-0.26 m/min,23.81%-51.40% and 22.79%-58.33%,102.4-293.7 kw/m and 116.0-322.9 kW/m,respectively. The different gaps of these fire behaviors were not obvious. Burning fire behaviors of ground fuel in pure forest of Pinus armandii Franch at approximately calm state in the laboratory were corresponded to the characteristics of small slope combustion,including burning steady,gently,with slowly small flames,and low fire intensity. While,in fields,there were many partial and semi-decomposition of stumps and large branches,even if ground fire had been extinguished,in a suitable condition,forest fire should occur and spread again.