大兴安岭白桦、山杨响应气候的先锋和伴生功能变化及对森林维系的树木年轮学研究

Climate change deeply affects the stability and balance of terrestrial forest ecosystem on the earth, however, forest plays an irreplaceable role on solving the environmental problems and alleviating the resource crisis. The pioneer and accompanying tree species determine forest formation, preserve and development as well as the principal species. It is important to mitigate the crisis of resources and environment, and maintain ecological security by knowing pioneer and accompanying tree species growth and climate response patterns and mechanisms under a climate change. In this study, based on the principles and technologies of dendrochronology, ecology and silviculture, coupled the results of field investigation, long-term eco-monitoring and indoor analysis and experiments, we select tree-ring of Betula platyphylla and Populus davidiana, which grow on the Great Xing'an Mountains, as study object, to study the typical pioneer and accompanying tree species' growing laws, growth - climate response and their linkage with forest environment and forest evolution, the tree-ring indicating pioneer and accompanying function variation, growth synergy and distribution decline with principal tree species (Larix gmelinii), and the crucial ecological process information of forest evolution. And then, we can optimize regulations and control measures, and management objectives on forest, improve and perfect early warning mechanism of ecological security on north forest under climate change for dealing with an accelerate warming climate.

气候变化深刻影响着陆地森林生态系统的稳定和平衡，而森林在解决环境问题，缓解资源危机方面起着不可替代的作用。森林中的先锋/伴生树种和建群树种一样决定着森林的形成、维系和发展。气候变化背景下，了解其生长模式和气候响应方式及机制，对于解决和缓解资源与环境危机、维护生态安全意义重大。本研究以生长于大兴安岭的白桦和山杨的树木年轮为研究对象，通过树木年轮学理论与技术，结合林学、生态学理论与技术，并将野外调查、长期监测和室内分析测试相结合，研究气候变化背景下典型先锋/伴生树种的生长规律、气候响应及其与森林环境和森林演变的关联，树木年轮变化指示的伴生或先锋功能波动，与主要树种（如落叶松）的生长协同和分布进退，以及关键森林演变的生态过程信息。进而优化森林的调控措施和经营目标，完善气候变化背景下北方森林生态安全预警机制，以应对加速变暖的气候环境。

先锋和伴生树种是维系特定森林生态系统结构和功能稳定的重要组成。本计划依托树木年轮学和森林生态学的理论和技术，重点以分布于我国大兴安岭林区的先锋和伴生树种山杨和白桦为研究对象，构建了我国林区东北山杨和白桦森林生态系统树木年轮数据库，研究了伴生树种的生长特点、气候响应规律及其全球气候变化背景下的潜在生长模式，即首次区域性地量化了我国北方森林主要先锋和伴生树种山杨和白桦及其主要相关树种的生长信息；明确了伴生和先锋树种山杨和白桦及其主要相关树种生长模式、生产力变化和气候的响应和适应特性；评估和预测了未来气候变化背景下其所代表森林的树木生产力的变化和适生区域的动态与趋势。研究结果填补了区域数据空白，为气候变化背景下森林生态的可持续发展提供了理论和数据支撑。