黄土残塬区刺槐林分结构与水土保持功能的作用机制

During the vegetation restoration in the Loess Plateau, the stand structures of many artificial forests are unreasonable, leading to the excessive consumption of water resources, the security threats of regional water and soil resources, and poor benefits in soil and water conservation. To solve these outstanding problems, this study selects the loess gully area and the typical Robinia pseudoacacia plantation as the objects. Based on the field survey data, the multi-factor relationship model of the stand structure and soil and water conservation function is constructed, using structural equations. And then, the technologies of the three-dimensional model, RS, and GIS are combined to realize the interaction process and the regulation verification process of the structure and the function. Through the three-dimensional visualization, the results show the quantitative and intuitive analysis of the interaction mechanism between them. Furthermore, the key structural factors could be determined, which affect the improvement of soil and water conservation function. And afterward, the results of the study provide a new theoretical evidence for the regulation of the stand structure and the optimization of soil and water conservation function, so as to promote the transformation of vegetation construction from sufficient quantity to excellent quality in the Loess Plateau.

为解决黄土高原植被恢复过程中，人工林林分结构不合理导致水资源过度消耗、区域水土资源安全受到威胁、林分水土保持效益不佳等一系列突出问题，本研究拟以黄土残塬区典型刺槐人工林为研究对象，基于野外调查数据，采用结构方程构建刺槐林分结构与水土保持功能的多因子作用关系模型，并融合三维模型、遥感和地理信息系统技术实现二者作用过程和调控验证过程的三维可视化展示，定量、直观解析林分结构与功能各因子的相互作用机制，进而判定促进或制约水土保持功能优化的关键林分结构因子，为黄土高原植被的林分结构调控、水土保持功能优化提供理论依据，推动黄土高原植被建设从数量充足向质量优良转变。

为解决黄土高原植被恢复过程中，人工林林分结构不合理导致水资源过度消耗、区域水土资源安全受到威胁、林分水土保持效益不佳等一系列突出问题，本研究以黄土残塬区典型刺槐人工林为研究对象，油松和华北落叶松人工林为对照，基于野外调查数据，采用结构方程构建刺槐林分结构与水土保持功能的多因子作用关系模型，并融合三维模型、遥感和地理信息系统技术实现二者作用过程和调控验证过程的三维可视化展示，定量、直观解析刺槐林分水平结构对拦沙减沙功能影响最为显著（0.85），并判定出影响水土保持功能优化的关键林分结构因子主要为林分密度和林木竞争指数，其总影响系数分别为-0.997和-0.998，初步确定其适宜密度范围1500-1800株/ha，并据此开展林分调控探究调控前后林分结构和功能的变化。结果表明林分密度、郁闭度、叶面积指数、草本多样性指数、枯落物持水性、土壤渗透性、植物根系等为主导因子；且刺槐和油松的吸水策略不同，二者混交可适应黄土高原的缺水条件。上述结论为黄土高原植被的林分结构调控、水土保持功能优化提供理论依据。