山苍子林分和环境因子与其经济指标的关联特征

Correlation characteristics between stand,environmental factors and economic indexes of Litsea cubeba

【目的】探究山苍子林分和环境因子与经济指标之间的关系,为山苍子林可持续经营和优质丰产提供理论参考。【方法】以福建清流、湖北太子山、浙江富阳三地的山苍子林为研究对象,采用协方差分析和相关性分析,对山苍子林分和环境因子及经济指标进行初步分析,并利用结构方程分析了山苍子单株产量、果实精油含量及精油中柠檬醛含量与胸径、树冠高、年平均降水量和年平均温度之间的关联特征。【结果】协方差分析结果表明:胸径、树冠高对山苍子单株产量有极显著影响(P<0.01),年平均降水量对单株产量有显著影响(P=0.034),年平均降水量和年平均温度对果实精油含量均有极显著影响(P<0.01)。相关性分析结果表明:单株产量与胸径、树冠高、年平均降水量、年平均温度均呈极显著正相关,相关系数分别为0.787、0.886、0.470、0.330。结构方程分析结果显示:胸径和树冠高对单株产量的直接效应系数分别为0.255(P<0.01)和0.668(P<0.01);年平均降水量和年平均温度对单株产量的直接效应系数分别为0.051(P=0.384)和0.048(P=0.380);各因素对单株产量的效应由强到弱依次为树冠高、胸径、年平均降水量、年平均温度;单株产量对果实精油含量的直接效应为负效应,其效应系数为-0.236(P<0.01)。【结论】胸径、树冠高、年平均降水量、年平均温度与单株产量均呈极显著正相关,且胸径和树冠高对单株产量的影响效应大于年平均降水量和年平均温度。因此,在山苍子经营过程中应注重胸径和树冠高的培育。

【Objective】Through the study of the relationship between stand,environmental factors and economic indicators of Litsea cubeba,a theoretical basis for the sustainable management and high-quality and high-yield of L.cubeba forest was provided.【Method】Taking L.cubeba forests in Qingliu,Taizishan and Fuyang as the research materials,the covariance and correlation among the stand,environmental factors and economic indexes were studied.The correlation characteristics between the yield of single plant,the content of essential oil in fruit,the citral content in essential oil and DBH,crown height,annual average rainfall and annual average temperature were studied by structural equation.【Results】The results of covariance analysis showed that DBH and crown height had a significant effect on the yield of L.cubeba(P<0.01),the average rainfall had a significant impact on the yield of L.cubeba(P=0.034),and the annual average rainfall and temperature had a significant impact on the content of essential oil in fruit(P<0.01).The results of correlation analysis showed that the yield per plant was significantly respectively correlated with DBH,crown height,annual average rainfall and annual average temperature,and the correlation coefficients were 0.787,0.886,0.470 and 0.330 respectively.The results of structural equation analysis showed that the direct effect coefficients of DBH and crown height on yield per plant were 0.255(P<0.01)and 0.668(P<0.01)respectively;the direct effect coefficients of annual average rainfall and annual average temperature on yield per plant were 0.051(P=0.384)and 0.048(P=0.380)respectively;the decreasing order of each factor effect on yield per plant was crown height,diameter at breast height,annual mean rainfall and annual mean temperature;the direct effect of yield per plant on essential oil content in fruit was negative,which coefficient was-0.236(P<0.01).【Conclusion】DBH,canopy height,annual mean rainfall,annual mean temperature and yield per plant were significantly positively correlated,and the effect of DBH and canopy height on yield per plant was greater than that of annual rainfall and temperature.Therefore,attention should be paid to the cultivation of DBH and crown height in the management of Litsea cubeba.