State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110164, PR China.
State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110164, PR China; School of Natural Resources, University of Missouri-Columbia, 203 Anheuser-Busch Natural Resources Building, Columbia, MO 65211-7270, USA.
Sci Total Environ. 2014 Sep 15;493:472-80. doi: 10.1016/j.scitotenv.2014.06.011. Epub 2014 Jun 22.
Fire significantly affects species composition, structure, and ecosystem processes in boreal forests. Our study objective was to identify the relative effects of climate, vegetation, topography, and human activity on fire occurrence in Chinese boreal forest landscapes. We used historical fire ignition for 1966-2005 and the statistical method of Kernel Density Estimation to derive fire-occurrence density (number of fires/km(2)). The Random Forest models were used to quantify the relative effects of climate, vegetation, topography, and human activity on fire-occurrence density. Our results showed that fire-occurrence density tended to be spatially clustered. Human-caused fire occurrence was highly clustered at the southern part of the region, where human population density is high (comprising about 75% of the area's population). In the north-central areas where elevations are the highest in the region and less densely populated, lightning-caused fires were clustered. Climate factors (e.g., fine fuel and duff moisture content) were important at both regional and landscape scales. Human activity factors (e.g., distance to nearest settlement and road) were secondary to climate as the primary fire occurrence factors. Predictions of fire regimes often assume a strong linkage between climate and fire but usually with less emphasis placed on the effects of local factors such as human activity. We therefore suggest that accurate forecasting of fire regime should include human influences such as those measured by forest proximity to roads and human settlements.
火灾显著影响北方森林的物种组成、结构和生态系统过程。我们的研究目的是确定气候、植被、地形和人类活动对中国北方森林景观火灾发生的相对影响。我们使用了 1966-2005 年的历史火灾点火数据，并采用核密度估计的统计方法得出火灾发生密度（火灾次数/平方公里）。随机森林模型被用来量化气候、植被、地形和人类活动对火灾发生密度的相对影响。结果表明，火灾发生密度具有空间聚集性。在该地区南部，人口密度较高（占该地区人口的 75%左右），人为引发的火灾发生高度聚集。在该地区海拔最高、人口密度较低的中北部地区，闪电引发的火灾聚集。气候因素（如细可燃物和凋落物湿度）在区域和景观尺度上都很重要。人类活动因素（如距最近定居点和道路的距离）仅次于气候，是火灾发生的主要因素。火灾制度的预测通常假设气候和火灾之间存在很强的联系，但通常较少强调人类活动等局部因素的影响。因此，我们建议，准确预测火灾制度应包括人类影响，如森林与道路和人类住区的接近程度。
