作 者 ：胡海清,赵致奎,王晓春*,张远东
期 刊 ：生态学报 2010年 30卷 23期 页码：6372~6379
Keywords:Daxing′an Mountains, fire scars, Mongolian pine, tree ring, fire history,
摘 要 ：大兴安岭地区是我国重要林区，又是林火的多发区，林火是森林生态系统中的重要干扰因子，对整个森林生态系统结构、功能和动态都有重要影响。樟子松为欧洲赤松的一个变种，在我国主要分布于大兴安岭地区。近年来，频繁的森林火灾造成樟子松林大面积减少。因此，重建大兴安岭樟子松林火历史，掌握樟子松林火灾规律已显得十分迫切。在大兴安岭北部塔河县蒙克山林场采集了11棵樟子松火疤圆盘，利用树木年轮年代学方法重建了大兴安岭北部塔河县蒙克山樟子松林的火灾历史，获得1个以树轮年代学为基础的樟子松火疤年表。利用火历史分析软件得到蒙克山樟子松林火灾间隔期和轮回期分别为24.8a和33a。由火疤年表得到的蒙克山樟子松林火灾历史大致可分为3个历史时期：满清中期（1723-1859年）、清末民国时期（1860-1949年）和建国后（1950年至今）。41个火疤记录中早早材火（E）所占比例最大，占全部火疤数目的61%，晚材火（A）、未确定火（U）和休眠季节火（D）则相对较少。大区域性火灾事件平均间隔期为32.5a，最大火灾间隔期为61a。本研究为进一步探究大兴安岭地区寒温带针叶林火灾历史的时间和空间格局及其之间的联系提供了基础数据。
Abstract:Daxing′anling region is not only one of the major forest zones but also one of the fire-prone forest areas in China. Forest fire, a major disturbance factor in this ecosystem, can influence the progress of an entire forest ecosystem. Pinus sylvestris var. mongolica Livt is a variety of Mongolian pine, and is found mainly in the Daxing′an Mountains. Frequent forest fires have recently caused a sharp decrease of Mongolian pine forest area. Therefore, we are now using tree-ring scars to reconstruct forest fire history and place current wildfires in a historical perspective. Eleven fire-scar discs were collected and used to create a fire chronology for the past 258 years. Sample preparation and crossdating took place at Mengkeshan of Tahe, located north of the Daxing′an Mountains. In the samples taken, the lowest number of fire scars was three and the maximum was seven. There were a total of forty-one scars recorded from the samples. Most of the scars came from the earlywood (61%), and the rest came from the latewood or could not be accurately determined. The earliest and latest forest fires in this chronology occurred in 1862 and 1987 respectively. Fires in 1883, 1925 and 1944 showed higher coherence among samples, which indicated that those fires were widespread, and could have been triggered by climate or by human factors. The biggest forest fire in the instrumental record was in 1987. This occurred right after the foundation of the P. R. China and was only found in one tree-ring sample. This gave evidence that not all violent forest fires were included in sampled tree-ring fire scars. The grand mean of individual tree-ring fire scars was 32.5 years, while the longest fire-free interval recorded for all trees that were sampled was 61 years in this area. Using the FHX2 software, mean fire interval (MFI) and fire return interval in the Mongolian pine forest of Mengkeshan were 24.8 and 33 years, respectively. Composite fire chronologies were tabulated on four levels. The 32.5 years composite MFI of this study is similar to the 37 and 37.2 years MFI from A′longshan in Daxing′an Mountains by Xu et al. and from northern Daxing′an Mountains by Hu et al. and the 21.7 years composite MFI in this report is a little longer than the 19.8 years MFI reported by Wang et al. The Mongolian pine forest fire history of Mengkeshan can be roughly divided into three historical periods depending on fire frequency distribution. During the mid-Qing Dynasty (1723-1859), there were few fire occurrences because of a “Closure Policy” and few human activities. During the period of late-Qing Dynasty and the Republic of China (1860-1949), forest fire numbers increased rapidly due to the “Open Policy”, huge crowds flocking into this area, and frequent wars. After the foundation of the P. R. China (1950-present), forest fire numbers decreased sharply because the new Chinese government implemented a strict forest prevention policy in Daxing′an Mountains region. This research provides basic data for studying forest fire spatio-temporal regime and its causal mechanisms in Daxing′an Mountains.
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