海岸沙地木麻黄林立地质量评价及类型划分

【目的】充分发挥海岸带木麻黄林地的生产潜力,为福建木麻黄人工林林分质量精准提升提供理论基础。【方法】基于福建省平潭岛海岸带木麻黄林样地调查和土壤分析,通过文献查阅,结合相关性分析筛选出影响木麻黄树高的主要养分因子,利用主成分分析方法对各样地多种土壤养分指标进行降维综合评价,并用聚类分析对所选样地土壤进行分级,最后结合立地因子的类别划分,运用数量化理论Ⅰ方法对木麻黄林立地条件进行立地质量评价和类型划分。【结果】海岸沙地木麻黄平均木树高与土壤有效磷呈极显著正相关(P <0.01);影响木麻黄生长的5个立地因子依贡献度大小分别为坡度(0.460 2)>风向(0.409 3)>土壤养分(0.292 1)>海拔(0.286 1)>土壤厚度(0.285 6),其中坡度和风向与优势木高偏相关系数达极显著水平(P <0.01),海拔、土壤厚度和土壤养分皆达到显著水平(P <0.05);平潭岛海岸沙地木麻黄林立地评价结果可分为5个等级,其中Ⅱ级(较适宜)占比最大,为43.1%,其后依次为Ⅳ级(勉强适宜)、Ⅲ级(适宜)、Ⅴ级(不适宜)和Ⅰ级(最适宜),适宜、较适宜和最适宜等级总占比66.7%。【结论】通过立地评价与类型划分,认为平潭岛海岸沙地大部分立地条件较适合木麻黄生长,营造木麻黄林应选择坡度<15°、海拔高度10~100 m的立地条件,但海岸沙地土壤养分较为贫瘠,以低、贫养分为主,沿海沙地木麻黄林的生长主要受磷限制,在造林和抚育中应注意磷肥的补充。

Quality evaluation and type division of Casuarina equisetifolia plantations on coastal dunes

【Objective】To maximize the production potential of coastal Casuarina equisetifolia woodland, preparing for the preliminary improvement of the quality of C.equisetifolia plantations in Fujian.【Method】Based on the survey data and soil data of the 51 C.equisetifolia plots in Pingtan, Fujian province, screened the main nutrient factors and related nutrient factors that affect tree height through related literature query and statistical correlation analysis methods, principal component analysis used SPSS for all plots of soil nutrients and more comprehensive evaluation index dimensionality reduction, hierarchical classification of soil in 51 plots used cluster analysis;classification based on site factors, combined with the quantitative theory I method to evaluate the site quality of the C.equisetifolia plantations site conditions.【Result】The mean tree height of the sample plots significantly positively correlated with the soil available phosphorus content(P < 0.01), the site factors affecting the growth of C. equisetifolia were determined according to their contribution degrees as slope(0.460 2) > wind direction(0.409 3) > soil nutrients(0.292 1) > elevation(0.286 1) > soil thickness(0.285 6). The correlation coefficient between slope and wind direction and dominant tree height are extremely significant(P< 0.01), and the elevation, soil thickness and soil nutrients have all reach out to the significant levels(P < 0.05), the evaluation results of the stand of C.equisetifolia on the coastal sandy land can be divided into five grades, which shows that the proportion of degree II(more suitable) in 51 sample plots is the highest, about 43.1%, followed by the next degree IV(barely suitable), degree Ⅲ(suitable), degree Ⅴ(unsuitable) and degree Ⅰ(most suitable). Appropriate, more appropriate and most suitable level total accounted for 66.7%.【Conclusion】Based on site evaluation and type classification, the coastal sandy land is more suitable for the growth of C.equisetifolia, it is believed that the site conditions of the C.equisetifolia plantation should be site conditions with a slope of < 15° and an altitude of 10-100 m;Coastal sandy soil nutrients are relatively barren, with low and poor nutrients as the mainstay. The growth of C.equisetifolia plantations in coastal sandy land is mainly restricted by phosphorus, it should be pay attention to the supplement of phosphate fertilizer in the afforestation and tending.