内蒙古森林火灾发生风险及其驱动因素

森林火灾是危害森林健康的主要灾害之一,科学预测森林火灾是预防森林火灾的重要依据。以中国新旧森林火灾政策作为分界线,将内蒙古森林历史火灾数据分为四个阶段,基于增强回归树模型建立内蒙古森林火灾发生模型,预测森林火灾发生情况,解释不同时期森林火灾和火灾风险变化的差异。预测结果表明:(1)4个时期建模精度AUC均大于0.94,表明BRT模型能够较好地预测研究区森林火灾的发生;(2)气温日较差、日最小相对湿度、上一年春防累计降水量、上一年秋防累计降水量、上一年春防最高地表气温海拔、距火点最近公路距离被确定为影响内蒙古森林火灾发生的重要驱动因素。(3)新旧《森林防火条例》实施前后森林火灾风险等级变化:1981-1988年3月14日,中、高和极高森林火灾风险区分布在呼伦贝尔的东部,而2009-2020年中、高和极高森林火灾风险区分布在呼伦贝尔南部和中部、赤峰市的西南部、锡林郭勒盟和呼和浩特市的中部、乌兰察布市和包头市的南部以及鄂尔多斯市的东部。有助于了解不同时期《森林防火条例》影响下的内蒙古森林火灾的驱动因素和火险等级的变化,为优化森林火灾管理政策及预测预报工作提供科学依据。

Risk of forest fire occurrence in Inner Mongolia and the impact of its drivers

Forest fire is one of the major disasters that jeopardize the health of forests, and scientific prediction of forest fire is an important basis for forest fire prevention. In this study, using China''s old and new forest fire policies as the dividing line, we divided the historical forest fire data of the Inner Mongolia into four periods, modeled the occurrence of forest fires based on the boosted regression tree (BRT) model, predicted the occurrence of forest fires, and explained the differences in the changes of forest fires and fire risks in different periods. The prediction results showed that: (1) the modeling accuracy area under curve (AUC) for all four periods was greater than 0.94, indicating that the BRT model was able to predict the occurrence of forest fires in the study area better; (2) The daily difference in temperature, daily minimum relative humidity, cumulative precipitation in the previous year''s spring control, cumulative precipitation in the previous year''s autumn control, the previous year''s spring control maximum surface temperature elevation, and the distance of the closest road to the fire point were identified as important drivers affecting the occurrence of forest fires in Inner Mongolia. (3) Changes in forest fire risk levels before and after the implementation of the old and new Forest Fire Prevention Regulations were as follows: from 1981 to March 14, 1988, the medium, high, and very high forest fire risk zones were distributed in the eastern part of Hulunbeier, while from 2009 to 2020 the medium, high, and very high forest fire risk zones were distributed in the southern and central part of Hulunbeier, the southwestern part of Chifeng City, the central Xilingol League and Hohhot, the southern Ulanqab and Baotou, and the eastern Ordos. The study helps to understand the drivers of forest fires and the changes in fire risk levels in the Inner Mongolia under the influence of the Forest Fire Prevention Regulations in different periods, and provides a scientific basis for optimizing forest fire management policies and forecasting.