四川盆周西缘天台山退化天然阔叶林主要乔木树种单木树冠特征

对地处四川盆周西缘山地的彭州市林场天台山林区的退化天然阔叶林中的红桦、房县槭、卵叶槭、野樱桃、稠李、灯台、椴树、五角枫和花楸等主9种主要乔木树种进行了树冠调查,并选择其平均木进行树干和枝解析,测定各单木树冠特征,包括全树高、平均冠幅、冠长、冠长率、一级枝数、二级枝条数、一级枝条着生密度、一级枝条年生长数、树冠曲线、树冠体积(大小)、树冠密度等。通过SPSS拟合其树冠曲线,利用V=∫baπf2(h)d(h)求得树冠体积,定义并计算了9个树种的树冠密度(枝密度)。研究结果表明:(1)阔叶树树冠曲线表现出稳定的抛物线特征;(2)各阔叶树树冠体积变化较大,符合其各自生物学特征;(3)阔叶树枝密度能反映其树冠生长状态,可作为树冠特征指标使用。

Studies of Individual-tree Crown Characteristics of Dominant Arbor Species in Degraded Natural Broad-leaved Forest on the Tiantai Mountain of Western Sichuan Basin Border in China

Investigation was made on the crown factors of nine dominant species （ Prunus padus, Cornuss controversa,Betula albo-sinensis burkiU, Tilia henryana coriaceifolia,Acerfranchebii pax,Sorbus pohuashanensis hedl） in degraded natural broad-leaved forest of Pengzhou forest farm located in Tiantai mountain on western Sichuan basin border, China. and analysis was made of stems and branches of their selected average tree. Surveying factors included total tree height ,average crown width, crown length, crown length ratio, primary branch number, secondary branch number, attached density of primary branch, primary branch number of annum growth, crown curve, crown volume （ size）, crown density and so on. With the help of SPSS, the crown curve was fitted, and the crown volume was calculated with the formula,V=∫baπf2（h）d（h） . The crown density was defined and calcu- lated. The research results showed that： （ 1 ） the crown profile of nine broad-leaved trees displayed the characteristic of steady parabolic curves, （2） the crown volumes （size） were changeful, and consistentwith their biological characteristics respectively, and （3） the crown density reflected the crown growth state ,and could be used as the index of expressing the crown characteristic.