寒温带典型森林应对气候变暖的弹性与适应性森林管理研究

Climate warming has changed boreal forest disturbance regimes, for example, the increasing frequencies of anomalous fire, drought susceptibility and insect outbreaks. All of these enhanced disturbances have increased the impacts on the boreal forest resilience significantly. For boreal forests of northeastern China, the effects of forest management practices have been found to be more important than climatic change; especially the previous harvest regime significantly influenced the forest composition and age structure. Because of the effects of historical factors, regional discrepancy and current forest management practices, the boreal forests are now on the status of fewer tree species occupied, even-aged structure, simple plant community, and low biodiversity. Recent studies have shown that the boreal forests are showing lower forest ecosystem resilience and adaption under climate warming. However, current boreal forests management practices were ignored the changing forest ecosystem resilience and adaptability caused by climate warming indirectly, also these forest management practices are rarely consider the sustainability under climate warming and the long-term effects on future forest ecosystem. In addition, we still do not know how to design forest management strategies to improve forest resilience under various climate warming scenarios. We selected the Great Xing'an Mountain as the study region, where has been labeled as the most important forest timber production in the past two decades and more sensitive to climate change and forest disturbance than other forests. This proposal intend to investigate three key research questions that integrate historical forest management data, field data collection, forest landscape model simulation and spatial statistical analysis, 1) quantitation of forest resilience at landscape scale, 2) prediction of the sustainability of current forest management practices for future forest ecosystem under climate warming, and 3) effects of climate warming and forest management strategies on forest ecosystem resilience. This research could provide scientific base for a sustainable forestry regional management which could improve the future forest resilience and adaptability under climate warming.

气候变暖通过改变森林干扰状态，显著增加了对北方森林生态系统弹性的影响。最新研究表明，受历史因素、区域差异以及现行管理措施影响，北方森林树种及年龄结构单一、群落简单、生物多样性低下，致使其在应对气候变暖时表现出较低的森林生态系统弹性和适应性。然而，目前森林管理措施却很少考虑其在气候变暖状况下的可持续性以及对森林生态系统弹性的长期影响，而且在未来气候条件下，对如何设计森林管理方案以提高森林生态系统弹性还缺乏深入了解。因此，本项目拟采用历史数据、野外调查、森林景观模型模拟和空间统计相结合方法，开展三方面研究：1）量化评估景观尺度上森林生态系统弹性高低；2）预测现行管理措施在气候变暖下的可持续性；3）气候变暖和森林管理方案对森林生态系统弹性的影响。本研究探讨气候变暖后森林管理方案对森林生态系统弹性的影响，定量我国北方森林生态系统弹性及其动态，为管理部门制定合理的长期森林管理策略提供科学依据。

近百年来，气候变化在不同尺度上直接影响森林生态系统的树种组成、年龄结构以及森林碳储量，同时，其也会通过改变自然干扰如林火等间接影响森林生态系统，最终影响北方森林生态系统弹性。北方森林受历史因素、区域差异以及现行管理措施等作用，树种及年龄结构单一，群落系统简单，生物多样性相对较低，致使其在应对气候变暖等外在影响时表现出较低的森林生态系统弹性和适应性。本项目基于历史数据、野外调查数据、森林景观模型模拟和空间统计相结合等方法，对大兴安岭地区森林景观进行了相关探究。在筛选相关森林生态系统弹性指标因子的基础上，量化了北方森林生态系统弹性时空动态变化，评估了当前气候条件下现行森林管理措施对森林生态弹性的影响，以及气候变暖条件下现行森林管理措施的可持续性；对比分析了气候变暖和森林管理方案下的森林生态系统弹性时空动态变化，明确了气候变暖和不同森林管理方案对研究区森林生态系统弹性和适应性的相对重要性，探讨了能够应对气候变暖提高森林生态系统弹性和适应性的森林管理方案。重要研究结果包括未来气候变暖后，现行森林管理措施将不能继续维持未来我国北方森林生态系统的弹性与适应性；从森林生态弹性数值变化角度出发，未来森林管理方案对森林生态系统弹性的影响将大于气候变暖对其造成的直接影响；未来森林管理方案在一定程度上可增加景观尺度森林生态弹性值；针对不同气候情景，需要设计不同的森林管理方案以提高未来森林生态系统弹性。本项目为森林生态系统弹性数值量化提供参考，明确了当前和未来气候变暖条件下大兴安岭地区森林生态系统弹性动态变化规律和森林管理方案实施效果，为该地区森林保护、经营和应对气候变暖提供了更为准确的科学依据。