抚育间伐调控黄土丘陵区刺槐人工林水分养分机理研究

Plantations in the loess hilly region had serious ecological problems now, such as simple structure, poor stability, low plant diversity and the declined of ecosystem services. To comprehensive understand the regulation mechanisms for the optimization of plantation composition and structure, and the promotion of ecosystem functions of plantations are new and important scientific question in the process of vegetation restoration after Sloping Land Conservation Program launched in this region. Thinning, a common and effective forest management technique, improves the growth of the remaining trees, enhances forest regeneration and biodiversity, and then affects forest ecosystem functions. Therefore, the high density Robinia pseudoacacia plantations in the loess hilly region is studied in this current pending project, using the wide range of field investigation and new fixed sample continuous monitoring methods, water and nutrients as the key indicators, try to study the effects of different thinning intensities on the stand composition, structure and productivity, plant water and nutrient use efficiency, litter production and nutrient returns, soil moisture and nutrient, and then to clarify the dynamic of the water and nutrients processes among plant-litter-soil under thinning treatment, and to reveal the regulation mechanism of water and nutrients processes for structure optimization and function promotion of Robinia pseudoacacia plantations in loess hilly region. The outcome of the current pending project would be providing a theoretical basis for the establishment of effective regulation mode of plantation structural optimization and functional upgrade in the loess hilly region.

黄土丘陵区人工林组成和结构简单、稳定性差、植物多样性低和生态服务功能低下等问题已十分突出。人工林组成结构优化与功能提升的调控机理研究是该区自退耕还林实施以来植被重建中所面临新的重要科学问题。抚育间伐是森林经营最有效的措施之一，可改善林木生长环境，提高林分质量，有利于林下植被生长和植物种群更新，进而影响森林的生态功能。本项目以黄土丘陵区现存高密度刺槐人工林为研究对象，采用大范围间伐迹地野外调查和新建抚育固定样地连续监测相结合的方法，以水分和养分限制因子为主线，研究不同抚育间伐强度对林分组成、结构及生产力、植物水分和养分利用效率、凋落物产量与养分归还、和土壤水分养分等指标的影响，阐明不同抚育强度对植物-凋落物-土壤间水分和养分供需协调的动态变化过程，揭示抚育间伐对黄土丘陵区刺槐人工林结构优化与功能提升的水分和养分调控机制，为该区建立人工林结构优化与功能提升的有效调控模式提供理论依据。

黄土丘陵区人工林结构简单、稳定性差、植物多样性低和生态服务功能衰退等问题已十分突出。人工林结构优化与功能提升的调控机理研究是该区自退耕还林实施以来植被重建中所面临新的重要科学问题。抚育间伐是森林经营最有效的措施之一，可改善林木生长环境，提高林分质量，有利于林下植被生长和植物种群更新，进而影响森林的生态功能。本项目在执行期间通过野外定位观测、面上调查和室内分析相结合的方法，较为系统地开展了不同抚育间伐强度（密度）及其不同林龄阶段刺槐人工林群落结构特征，不同组分、层次生态化学计量特征，土壤水分、养分特征及其利用效率等研究，取得了系列研究结果，对于揭示抚育间伐（密度调节）后的刺槐人工林组成结构演变特征及其功能提升的机制提供了重要理论依据，研究结果可以为该区刺槐人工林的经营与管理提供技术支撑。在本项目的资助下，共发表相关论文10篇，其中SCI收录5篇；培养研究生7名，其中硕士6名，博士1名。