寒温带兴安落叶松生长对气候响应差异的生物因素探究

Considering former research focus on the common response of Larix gmelinii radial growth to climate change, neglect the biological factors such as tree age and competition may cause variation on response, these could inhibit comprehensive understanding how the climate change influence on radial growth of Larix gmelinii. The research is focus on Greater Khingan mountain area’s regional typical plant.larix gmelinii, analysis the influence of age and competition on individual tree.ring growth response to climate change on differ habitat.The specific objective of this study include: elucidate the tree scale variability of tree ring growth and tree ring growth response to climate; identify the influence of age and competition on tree scale tree ring growth response to climate change; identify the influence of age and competition on tree scale tree ring growth response to extreme drought; the spatial character of tree ring growth response to dominate climate index and extreme drought under differ age and competition condition. Through study the influence of age and competition on geographic patterns of relationship between larix gmelinii's tree ring growth and climate, we can investigate how the sensitivity of tree-ring growth to climate change modulated by biological factors, we can also valuable ecology informations on how climate change influence larix gmelinii and dynamic of forest in these area. These will helpful for setup sustainable forest management system and provide a theoretical basis on how to protect these valuable forest in the situation of climate change.

针对目前有关气候变化对兴安落叶松生长影响研究忽略树龄、竞争等生物因素导致生长对气候响应差异特征及近年来极端干旱发生频率增加对生长适应性可能影响，存在难以全面了解气候变化如何通过树木生长及生长对气候响应变化影响着森林生态系统问题。本项目以大兴安岭兴安落叶松林为研究对象，在单木尺度上分析不同生境条件兴安落叶松径向生长对气候变化的响应与适应受树龄、竞争调节特征。研究内容主要包括：不同生境条件径向生长变异特征和径向生长对气候响应变异特征；不同生境条件树龄、竞争对生长-气候响应和生长-极端干旱适应性调节特点及变化规律；不同树龄，竞争压力的树木径向生长对主要气候因子响应和对极端干旱适应性空间格局及变化规律。本项目通过探索树龄、竞争对兴安落叶松生长-气候响应和生长-极端干旱适应性影响时空变化，为深入了解气候变化对兴安落叶松适应性、稳定性影响和森林动态变化提供有价值信息。

大兴安岭是我国升温最快，树木生长对气候变暖最为敏感的地区之一。为了解生物因素对兴安落叶松（Larix gmelinii）生长-气候响应时空动态特征影响，本研究从单木和林分尺度上分析不同生境条件兴安落叶松径向生长对气候变化的响应与适应受树龄、竞争调节特征。研究内容主要包括：不同生境条件径向生长变异特征和径向生长对气候响应变异特征；不同生境条件树龄、竞争对生长-气候响应和生长-极端干旱适应性调节特点及变化规律；不同树龄，竞争压力的树木径向生长对主要气候因子响应和对极端干旱适应性空间格局及变化规律。主要发现包括：（1）热量条件限制减弱导致树木生长受生物因素影响加强，呈现个体间的生长一致性下降趋势；（2）热量条件限制减弱后树木个体间生长的一致性与降水关系加强，水分不足会导致生长一致性上升；（3）兴安落叶松对干旱的适应能力较强，大径级树木对干旱的抵抗力和恢复弹力更低，对干旱的适应能力更弱；（4）快速升温会加剧水分胁迫，导致兴安落叶松生长急剧下降并出现不同程度的生长衰退趋势；（5）兴安落叶松对干旱的抵抗力和恢复弹力随纬度升高而降低；（6）研究区范围较高纬度的兴安落叶松对干旱的适应能力较弱，出现生长衰退的频率和强度最高。研究结果证实气候因子限制性减弱（增强）会加大（减小）生物因素对树木生长影响，我们需要充分了解温度持续上升和日益严峻的干旱胁迫对于兴安落叶松生长产生的不利影响，这对我们保护这片具有重要生态意义森林十分重要。