Nonparametric multivariate analysis of variance for affecting factors on the extent of forest fire damage in Jilin Province, China

Forest fires are influenced by several factors,including forest location,species type,age and density,date of fire occurrence,temperatures,and wind speeds,among others.This study investigates the quantitative effects of these factors on the degree of forest fire disaster using nonparametric statistical methods to provide a theoretical basis and data support for forest fire management.Data on forest fire damage from 1969 to 2013 was analyzed.The results indicate that different forest locations and types,fire occurrence dates,temperatures,and wind speeds were statistically significant.The eastern regions of the study area experienced the highest fire occurrence,accounting for 85.0%of the total number of fires as well as the largest average forested area burned.April,May,and October had more frequent fires than other months,accounting for 78.9%,while September had the most extensive forested area burned(63.08 ha)and burnt area(106.34 ha).Hardwood mixed forest and oak forest had more frequent fires,accounting for 31.9%and 26.0%,respectively.Hardwood-conifer mixed forest had the most forested area burned(50.18 ha)and burnt area(65.09 ha).Temperatures,wind speeds,and their interaction had significant impacts on forested area burned and area burnt.

火干扰后短期白桦林和落叶松林土壤呼吸及其组分的影响

以小兴安岭2种典型林型(落叶松林和白桦林)的火后短期(火烧后1年内)土壤呼吸为研究对象。对火烧迹地与对照样地的土壤呼吸进行测定,比较火干扰后短期内火烧迹地与对照样地土壤呼吸的变化。结果表明:2种林型同一月份火烧与对照样地之间土壤呼吸速率差异最显著的月份均出现在8月(P<0.05),其他月份差异不显著(P>0.05),但火干扰后短期内白桦林的土壤呼吸总平均值有所下降,落叶松林略有增加,具体表现为白桦林火烧样地生长季土壤总呼吸平均值(3.91μmol·m-2·s-1)明显低于对照样地(5.29μmol·m-2·s-1),自养呼吸和异养呼吸同样小于对照样地,4个月的土壤呼吸总平均值火干扰后亦下降。落叶松林火烧样地生长季土壤总呼吸(4.62μmol·m-2·s-1)高于对照样地(4.18μmol·m-2·s-1),自养呼吸(火烧0.76μmol·m-2·s-1高于对照0.50μmol·m-2·s-1)和异养呼吸(火烧3.86μmol·m-2·s-1高于对照3.67μmol·m-2·s-1)同样大于对照样地,并且4个月的总平均值火干扰后亦有所升高;在回归模型中白桦林和落叶松林5 cm处土壤温度,土壤湿度以及其交互作用共同解释土壤总呼吸的82.9%和88.6%,火干扰后白桦林的解释比例为88.8%有所上升,落叶松林为72.9%有所降低。本研究旨在估测火干扰对土壤呼吸的影响,为火干扰对土壤呼吸的短期影响研究提供基础数据,为更深入地研究土壤呼吸对火干扰的响应提供参考依据。

河北省围场县森林火险区划研究

以围场满族蒙古族自治县作为研究区,利用森林资源二类调查数据、DEM数据和地形图,以GIS技术作为支撑,选取地物类型、地形因子以及人类活动和交通区位作为主要林火影响因子,采用因子加权重置综合分析法计算围场县各个乡镇的森林火险指数。根据计算出的森林火险指数,将所有乡镇分为低火险、中火险、高火险和极高火险4类火险区。结果表明,低、中、高和极高火险区分别占研究区的2.73%、36.50%、57.72%和3.41%,极高或高火险区主要集中在塞罕坝机械林场和御道口牧场东北部;中火险区主要位于御道口牧场;低火险区则集中在卡伦后沟牧场和红松洼国家级自然保护区。最后通过对划分的火险区进行了总体、地域的分析,并提出了预防对策。此研究可以为围场县的森林火灾管理提供有价值的参考。