黄河故道沙区河南段刺槐人工林普遍存在退化现象,导致区域生态防护功能下降。准确、科学地评估其退化等级对于退化林修复工作具有重要意义。以国有中牟县林场的刺槐人工林为研究对象,构建包括林分生产力、林分立地条件、林分抵抗力及林分结构4个维度22个指标的林分健康状态评价指标体系,采用偏最小二乘法结构方程模型(PLS-SEM)确定指标权重,使用健康评价指数、K均值聚类及Fisher判别分析对研究区44个样地健康状态进行综合评价。结果表明:1)PLS-SEM模型通过信效度、拟合度及影响显著性检验,具有可靠性。2)模型确定的林分生产力、林分立地条件、林分抵抗力及林分结构的权重分别为0.257、0.233、0.256和0.254。3)刺槐人工林健康评价指数范围为2.266~3.272。其中,11.4%处于健康状态,25.0%处于亚健康,45.4%处于中健康状态,18.2%处于不健康状态。研究发现,林分生产力与林分抵抗力是影响河南黄河故道刺槐人工林健康的关键维度。其中,平均树高是构成生产力的最关键指标,而外部干扰则是制约抵抗力的核心胁迫因子。

The Robinia pseudoacacia plantations in the sandy areas of the Yellow River floodplain in Henan Province exhibit a widespread degradation trend,significantly impacting the regional ecological environment.Accurately and scientifically evaluating their health status is critical for the restoration of degraded forests.This study focused on the R.pseudoacacia plantations in Zhongmu Forest Farm,located in the Yellow River floodplain of Henan Province.With field investigationsconductedin 44 representative plots,22 indicators across four dimensions involving stand productivity,stand site,stand resistance and stand structure were selected.Using Partial Least Squares Structural Equation Modeling(PLS-SEM),K-means clustering analysis,and Fisher discriminant analysis,a health assessment system and a health index model suitable for this region were established,followed by a comprehensive evaluation of stand health status.The results showed that the constructed PLS-SEM passed tests of validity,model fit,and significance.By using the PLS-SEMmodel,the weights of the four latent variable layersof stand productivity,stand site,stand resistance,and stand structure,were determined as 0.257,0.233,0.256,and 0.254,respectively.The health evaluation index of the studied R.pseudoacacia plantations ranged from 2.266 to 3.272.Among them,11.4% were in a healthy state,25.0% in a sub-healthy state,45.4% in a moderately healthy state,and 18.2% in an unhealthy state.The comprehensive findings indicate that stand productivity and stand resistance are the key dimensions determining the health of R.pseudoacacia plantations in the Henan Yellow River Old Course area.Specifically,mean tree height was identified as the most critical indicator of stand productivity,while external disturbance emerged as the primary constraining factor for stand resistance.