元宝山南方红豆杉种群结构——Ⅱ、高度结构

在资源调查的基础上选择样地 ,采用样方调查法研究红豆杉种群高度结构 ,结果表明南方红豆杉种群是通过茎干萌生幼苗 (构件 )来延续和扩大的 ,其结构为塔型 ,存活曲线为中间微凸而近于直线 ,是稳定型种群结构。幼苗幼树级占 95.3% ,其次为高度 9.1～ 11m的成年树级 ,占 1.6 %。为了扩大和延续 ,南方红豆杉种群通过大量萌生 (繁殖 )构件并进行自我调节 ,使幼树幼苗有较高的死亡率 ;种群个体进入优势层后 ,高度生长缓慢 ,而径向生长加快 ,因此 9.1～ 11m级数量增多。种间种内竞争的结果形成南方红豆杉种群世代不同大小个体的高度结构。南方红豆杉种群高度与胸径的关系为幂函数相关关系 ,高度与年龄 (<6 0 a)的关系为线性相关关系

Structure of Taxus chinensis var. mairei population in Yuanbaoshan of Guangxi,China--Ⅱ.Height structure

Based on the resource investigation into Taxus chinensis var. mairei ,plot sampling was selected and quadrate was used to study the community. The results showed that the development of Taxus chinensis var. mairei populations greatly relied on its modules which sprout on its stem. The height structure was “revere J”, and the survival curve was likely a linear with a little protruding so that it was belonged to stable type. The seedling and sapling accounted for 95 3% of total number, while the mature trees of H: 9 1～11 m class for 1 6% whose density was just next to the sapling class. Expanding and continuing the population induced a higher seedling and sapling mortality rate. When the individual high enough to gain spatial it grow mainly in diameter. So the number of mature tree of 9 1～11 m class increased .The results of intraspecific and interspecific competition formed the different individual height of Taxus chinensis var. mairei population. The relationship between height and stem size ofTaxus chinensis var. mairei was significant which was a power function, while height and age (<60 year ) was also significant but a linear function.