| 摘要: |
| 以大兴安岭地区兴安落叶松（Larix gmelinii）为研究对象，分别选取1987年、2003年和2015年火干扰区域及其附近未受火干扰区域设置典型样地，基于树轮数据和调查数据重建历史直径结构，构建兴安落叶松树木生长与气候因子的相关关系，探讨气候变化背景下火干扰对兴安落叶松直径结构的影响。研究结果表明：（1）火干扰下兴安落叶松直径结构呈正偏，高峰态分布。中度火干扰恢复15年后则呈现负偏、峰度值下降的趋势，而重度火干扰恢复15年后仍处于正偏高峰态分布，但随后趋向负偏，低峰态分布。（2）火干扰改变了兴安落叶松直径生长与气候之间的响应关系，中度火干扰下兴安落叶松生长与上年冬季温度呈显著负相关（p＜0.05），随着火干扰强度增加，降水的抑制作用增强，重度火干扰下兴安落叶松直径生长与当年生长季（5—8月）、上年生长季（7—9月）和上年冬季（11—12月）降水呈显著负相关关系（p＜0.05）。不同恢复期内树木生长-气候因子关系也有所差异。中度火干扰下兴安落叶松与生长季温度的关系由火干扰初期正相关转变为中期（恢复15年）负相关（p＜0.05），与上年生长季降水的关系则转变为正相关关系（p＜0.05）；重度火干扰下兴安落叶松直径生长与上年冬季温度由恢复初期的负相关转变为后期（恢复31年）的正相关（p＜0.05），与当年生长季降水转变为负相关（p＜0.05）。在未来气候变暖和火干扰事件增加的趋势下，兴安落叶松直径结构趋向负偏、高峰态分布。 |
| 关键词: 直径结构 火干扰强度 气候因子 兴安落叶松 |
| DOI：10.7515/JEE192059 |
| CSTR： |
| 分类号: |
| 基金项目:国家重点研发计划（2017YFC0504003-1） |
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| Relationship between diameter structure dynamics and climate factors of Larix gmelinii under fire disturbance |
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CHEN Junyu, LIU Mingqian, YANG Jing, WANG Anbin, MA Shenyuan, GAO Lushuang
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1. College of Forestry, Beijing Forestry University, Beijing 100083, China
2. Key Laboratory of Forest Resources and Environmental Management, Beijing Forestry University, National Forestry and Grassland Administration, Beijing 100083, China
3. Forest Management Engineering Technology Research Center, National Forestry and Grassland Administration, Beijing 100083, China
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| Abstract: |
| Background, aim, and scope Diameter structure plays a decisive role in the future development of a forest. Using tree-ring data and survey data in a climate change background, we explore changes in the relationships between fire disturbance, the growth of Larix gmelinii (larch), and climate change by reconstructing the historical diameter structure. Materials and methods In this study, we investigate L. gmelinii in areas disturbed by fire in 1987, 2003, and 2015 in the Greater Khingan Mountains. Nearby areas not disturbed by fire are selected as control sites. Results (1) Fire disturbance caused the diameter structure of L. gmelinii to be positively deviated and the kurtosis value increased. After 15 years of recovery from moderate fire disturbance, there was a negative bias and the kurtosis value decreased. Fifteen years after recovery from severe fire disturbance, it remained positive and reached the peak of kurtosis but then showed a tendency to negative bias, and the kurtosis value decreased. (2) Fire disturbance changed the response relationship between the diameter growth of L. gmelinii and climate. Under moderate fire disturbance, the growth ofL. gmelinii was steadily and significantly negatively correlated with the winter temperature of the previous year (p＜0.05). The positive correlation with the temperature in the growing season changed from positive in the initial stage of fire disturbance to a negative correlation in the mid-term (15 years of recovery) (p＜0.05), while the relationship with precipitation in the growing season of the previous year was positively correlated (p＜0.05). Under severe fire disturbance, the diameter growth of L. gmelinii was significantly negatively correlated with precipitation in the current growing season (May—August), the previous year’s growing season (July—September), and winter of the previous year (November—December) (p＜0.05). The negative correlation with the winter temperature of the previous year changed from the initial period of recovery to a positive correlation (p＜0.05) in the later period (31 years of recovery), and a negative correlation with a change in precipitation in the current growing season (p＜0.05). Discussion Different fire disturbances can change the diameter structure of L. gmelinii by changing the forest’s light intensity, degree of competition, and soil composition. With increased recovery time, the distribution of the diameter of L.gmelinii forest is difficult to restore to the original ecological state. Under global warming, the growth of L. gmelinii in the Greater Khingan Mountains will be more sensitive to climatic factors, with increased temperatures increasing the respiration of L. gmelinii, promoting growth and development. Transpiration led to a change in the water distribution pattern of larch in the Greater Khingan Mountains and a decrease in environmental water content, which hindered growth. Fire disturbance can also change the diameter structure of the forest stand, which in turn can change the response of larch growth in the Greater Khingan Mountains to climate change. Conclusions (1) Increased fire intensity has a suppressive effect on diameter growth. Prolonged fire disturbance recovery time promotes diameter growth, and forest restoration time is shorter under moderate fire disturbance conditions than under severe fire disturbance conditions. (2) Fire disturbance changed the response relationship between the diameter growth of L. gmelinii and the climate in the Greater Khingan Mountains. The diameter growth showed an obvious lag response to temperature and precipitation. Under future climate warming conditions, the diameter distribution of L. gmelinii may move to a small and medium diameter level. Simultaneously, the diameter growth rate after fire disturbance will slow significantly, the recovery process from fire disturbance will be longer, and it will be difficult to restore the larch to its original natural state. Recommendations and perspectives Under the trend of increasing global warming and increasing fire disturbance events, the response relationship between the diameter structure of L. gmelinii in the Greater Khingan Mountains and the climate may change significantly under the influence of fire disturbance. This warrants further research and scrutiny. |
| Key words: diameter structure fire disturbance intensity climatic factors Larix gmelinii |
