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Characteristics of fuel load distribution in typical subtropical forest types
LI Jianhua, XIA Honglu, TANG Weiping, HUANG Han
JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (5) : 57-64.
PDF(2321 KB)
PDF(2321 KB)
Characteristics of fuel load distribution in typical subtropical forest types
【Objective】The fuel load is important for forest fire management. This study investigated the distribution of fuel load and analyzed the relationship between the per unit area fuel load components and volumes, within the tree layer among subtropical forest types, to provide scientific references for sustainable forest management. 【Method】Forest fire survey and supplementary investigation data were taken from Huzhou City, Zhejiang Province. Nine typical subtropical forest types were chosen as research objects. The fuel load per unit area of each component of different forest types was measured and calculated by quadratic investigation and drying methods. One-way ANOVA was used to test for differences of the fuel load per unit area among forest types and components. The linear or nonlinear correlation fitting was carried out on the fuel load per unit area of the components and the volume per unit area of the tree layer of typical forest types to analyze their correlation.【Result】The amount of the fuel load per unit area of tree layer in most forest types was significantly higher than that in the fallen dead wood layer (P< 0.05), and the fallen dead wood layer was significantly higher than other components such as the shrub layer (P< 0.05). However, the fuel load per unit area of the fallen dead wood layer in Phyllostachys edulis monoculture forests was significantly higher than that of other components (P< 0.05). The fuel load per unit area in the tree layer of Quercus spp. forests, Schima superba forests, and coniferous and broad-leaved mixed forests were higher than that of other forest types. The fuel load per unit area of the litter layer in coniferous and broad-leaved mixed forests, Schima superba forests, and other soft broad-leaved forests were higher than that of other forest types. The results of the regression analysis showed that for most forest types, there was a significant linear positive correlation between fuel load per unit area and volume per unit area of tree layer. Among them, Quercus spp. forests have the highest correlation (R2=0.89). Nevertheless, the amount of the fuel load per unit area in the shrub layer and herb layer in most forest types decreased with the increase of the amount of volume per unit area.【Conclusion】The management of subtropical forest fuel loads should take full account of the differences in the distribution characteristics of different forest types and the interrelationship among different components. The composition of tree species in the canopy layer has a significant impact on the distribution of forest surface fuels. The storage volume per unit area of tree layer is closely related to the fuel load per unit area of tree layer and is an important reference indicator for the analysis and prediction of fuel loads of forest components.
combustible load / tree species composition / stand volume / One-way ANOVA / regression fit / subtropical forest
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森林可燃物是森林生态系统的基本组成部分, 是影响林火发生及火烧强度的重要因素之一, 因此, 受到国内外学者的广泛关注。该文从以下4个方面综述了国内外可燃物研究的最新进展: 森林可燃物特性, 森林可燃物类型与火行为, 森林可燃物类型、载量的调查与制图, 森林可燃物管理。同时提出了我国森林可燃物今后的研究方向: 开展多尺度可燃物研究; 可燃物类型与火行为的研究; 把以试验观测为基础的静态研究与以空间技术和生态模型为基础的动态预测相结合, 研究可燃物处理效果; 全球气候变化背景下可燃物处理与碳收支。
Fuel is the basic component of forest ecosystems. It is one of the most important factors that influence forest fire ignition and fire severity. Hence, it has drawn much attention from researchers worldwide. We reviewed the current status of forest fuel studies from four aspects: 1) forest fuel properties, including physical and chemical properties, and flammability of forest fuels, 2) fuel models and fire behaviors, 3) methodologies for inventory and mapping of fuel types and fuel loads, and 4) forest fuel management. We also discuss the future direction in forest fuel studies, including 1) forest fuel studies at site, regional, and country-wide scales, 2) fuel models and fire behaviors, 3) combining observational and experimental studies with computer simulation and spatial analysis technologies for long-term predictions of fuel treatment effects over large landscapes, and 4) fuel treatment and carbon budget under global climate change. There are significant implications for forest fire management and forest fuel research in China.
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为研究可燃物负荷量空间分布对林火种类和火行为的影响,以川西南地区不同类型云南松林的冠层可燃物和地表可燃物、4个地形因子(海拔、坡度、坡位和坡向)和4个林分因子(郁闭度、胸径、树高和林龄)为对象,比较不同林分相同垂直层面和不同空间层次上的可燃物负荷量及分布特征,分析不同林分的林火行为趋势；并运用典型相关分析（CCA）分析可燃物负荷量与环境因子的关系.结果表明： 不同林分组成中,可燃物垂直分布呈显著性差异.云南松-栎类-丁香林、云南松-栎类林和云南松纯林容易发生地表火,但不易发生树冠火；云南松-侧柏林、云南松-油杉林和油杉-云南松林易发生地表火,而且易转化为树冠火.冠层可燃物主要受林龄、海拔、胸径和树高的影响,林下可燃物主要受郁闭度、坡度、树高和林龄的影响.
In order to understand the effects of fuel loadings spatial distribution on forest fire kinds and behaviors, the canopy fuels and floor fuels of <em>Pinups yunnanensis</em> forests with different canopy density, diameter at breast height (DBH), tree height, and stand age and at different altitude, slope grade, position, and aspect in Southwest China were taken as test objects, with the fuel loadings and their spatial distribution characteristics at different vertical layers compared and the fire behaviors in different stands analyzed. The relationships between the fuel loadings and the environmental factors were also analyzed by canonical correspondence analysis (CCA). In different stands, there existed significant differences in the vertical distribution of fuels. <em>Pinus yunnanensis</em>oak<em>Syzygium aromaticum</em>, <em>Pinus yunnanensis</em>oak, and <em>Pinus yunnanensis</em> forests were likely to occur floor fire but not crown fire, while <em>Pinus yunnanensis</em><em>Platycladus orientalis</em>, <em>Pinus yunnanensis</em><em>Keteleeria fortune</em>, and <em>Keteleeria fortune</em><em>Pinus yunnanensis</em> were not only inclined to occur floor fire, but also, the floor fire could be easily transformed into crown fire. The crown fuels were mainly affected by the stand age, altitude, DBH, and tree height, while the floor fuels were mainly by the canopy density, slope grade, altitude, and stand age.
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