【摘要】 梭梭和柠条作为石羊河下游荒漠区生态安全屏障建设的主要树种，分布面积大，在防风固沙、固碳增汇等方面发挥着重要的作用。近20年来，随着地下水位的下降和气候干旱化，梭梭柠条人工林已出现不同程度的衰败和死亡。选择20 a及以上林龄的梭梭、柠条、梭梭+柠条3种林分，对其生长指标、病态指标、更新指标及多样性指标调查，运用模糊判别法从优势种和林下植被两方面评价林分健康状况。结果表明：(1)石羊河下游梭梭柠条整体处于中等健康及以下水平。(2)梭梭柠条混交林健康状况相对优于柠条林、梭梭林，柠条的病虫害轻于梭梭，发芽指数高于梭梭。(3)土壤含水量与其健康序列有明显的正向相关性，健康序列越高含水量越高，全盐量、有机质、速效P分别明显影响着梭梭柠条的高生长、幼苗更新、盖度、枝条发芽和生活型。更多还原

【Abstract】 Haloxylon ammodendron and Caragana korshinskii are the main tree species for the construction of ecological security barrier in the desert area of the lower reaches of Shiyang River. They have a large distribution area and play an important role in windbreak and sand fixation, carbon sequestration increase and other aspects. In the past twenty years, with the decline of groundwater level and the drought of climate, Haloxylon ammodendron and Caragana korshinskii plantations have declined and died in varying degrees. Three forest stands of Haloxylon ammodendron,Caragana korshinskii,Haloxylon ammodendron + Caragana korshinskii with 20 years and above were selected to investigate their growth index, pathological index, regeneration index and diversity index. The fuzzy discriminant method was used to evaluate the health status of the stand from two aspects of dominant species and understory vegetation. The results showed as the following three aspects.(1) The overall health of Haloxylon ammodendron and Caragana korshinskii in the lower reaches of Shiyang River was in the middle and below level.(2) The health status of the mixed forest of Haloxylon ammodendron and Caragana korshinskii was relatively better than that of Caragana korshinskii forest and Haloxylon ammodendron forest. The disease and insect damage of Caragana korshinskii was lighter than that of Haloxylon ammodendron,and its germination index was higher than that of Haloxylon ammodendron.(3) There was a significant positive correlation between soil water content and its health sequence. The higher the health sequence was, the higher the water content was.The total salt content, organic matter and available P significantly affected the height growth, seedling regeneration, coverage, branch germination and life form of Haloxylon ammodendron and Caragana korshinskii.更多还原