Active fires show an increasing elevation trend in the tropical highlands
Active fires show an increasing elevation trend in the tropical highlands
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DOI：
10.1111/gcb.16097
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发表时间：
2022-01
影响因子：
11.6
通讯作者：
Chi-wei Xiao;Zhi-ming Feng;Peng Li
中科院分区：
文献类型：
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作者：
Chi-wei Xiao;Zhi-ming Feng;Peng Li
作为地球生态系统的一个固有要素，森林和植被火灾是气候变化的主要促成因素和直接后果之一。鉴于地形是森林景观和火灾行为的关键驱动因素之一，澄清全球火灾事件的地形特征和趋势非常重要，特别是在热带地区。在这里，我们使用可用的MODIS Collection 6活动火灾产品（2001-2019）调查了大陆到全球范围内的活动火灾海拔变化，包括热带，热带外，低地和高地（海拔超过200米[asl]）。主要结论如下：（1）全球年活动性火灾事件总数（平均450万起）呈下降趋势，其中97%以上频繁发生在海拔1500 m以下。(2)热带和高地分别占全球活跃火灾的74%（±3%）和71%（±2%），其中77%（±2%）发生在热带高地。(3)从世纪开始，高地的火灾呈上升趋势，特别是在热带地区，而低地则呈相反的趋势。更重要的是，高地海拔上升的速率比低地海拔下降的速率大。(4)最后，联合国关于降低发展中国家因森林砍伐和退化所产生的排放的合作方案（UN-REDD）似乎减缓了甚至扭转了伙伴国家热带地区火灾发生率上升的趋势，特别是在低地。在全球气候变化和火灾猖獗的背景下，特别是在热带高地，发生活跃火灾的海拔有上升的趋势，这表明更多的植被燃烧事件发生或将发生在丘陵和山区，从而对热带森林和一些重要的生物多样性保护区构成进一步威胁。各国政府和科学界应做出更持续的努力，鼓励加强火灾管理实践，并开展深入的研究计划。
As an inherent element of the Earth's ecosystem, forest, and vegetation fires are one of the key contributors to and direct consequences of climate change. Given that topography is one of the key drivers of forest landscapes and fire behavior, it is important to clarify what the topographical characteristics and trends of global fire events are, particularly in the tropics. Here, we have investigated the variations in elevation of active fires at the continental to a global scale, including the tropics, the extra‐tropics, the lowlands, and the highlands (greater than 200 m above sea level [asl]), using the available MODIS Collection 6 active fire products (2001–2019). The main conclusions are: (1) the annual totality (average of 4.5 million) of global active fire events decreased and over 97% of them occurred frequently below 1500 m asl. (2) The tropics and the highlands accounted for ~74% (±3%) and 71% (±2%) of global active fires, respectively, and 77% (±2%) were observed in the tropical highlands. (3) From the beginning of the 21st century, active fires in the highlands displayed an upward elevational trend, particularly in the tropics, while the opposite trend was observed for the lowlands. More importantly, the rate of the increasing elevation in the highlands had a greater magnitude than that of decreasing elevation in the lowlands. (4) Finally, the United Nations collaborative program on Reducing Emissions from Deforestation and Forest Degradation (UN‐REDD) in Developing Countries seemed to slow down or even result in a reversal of the upward elevational trend of fire occurrences in the tropics for the partner countries, especially in the lowlands. In the context of global climate change and rampant fires, the trend of rising elevation for active fire occurrences, particularly in the tropical highlands, indicates that more vegetation burning events occur or will occur in hilly to mountainous areas, thus posing further threats to tropical forests and some important biodiversity refuges. More sustained efforts should be made by governments and the scientific community to instigate enhanced fire management practices and to conduct in‐depth research programs.