毛竹林种群结构特征变化的海拔效应研究

Influence of Altitude on Population Structure Characteristic of Moso Bamboo Forest

在毛竹分布南缘的中亚热带与南亚热带气候过渡区,选择土壤、坡度、坡向、经营水平等一致的3个海拔梯度毛竹林,对种群结构随海拔的变化规律进行了研究,结果表明:立竹密度随海拔的升高显著下降,分株间非对称竞争趋于激烈;立竹胸径随海拔的升高显著增大,海拔每上升100 m,立竹平均胸径增加0.65 cm;海拔对立竹枝下高、全高有明显影响,随海拔的升高,相同径级立竹的枝下高、全高趋于增大,海拔对立竹枝下高的影响比立竹全高更为深刻;立竹整齐度、均匀度随海拔的升高显著降低;试验区低、中、高海拔毛竹林适宜的经营类型分别为笋苗兼用林、笋用林、笋材两用林。

In the transition area of middle boundary of Moso bamboo distribution, the subtropical and south subtropical, the southern Moso bamboo stands with same soil type, slope gradient, slope aspect and management level were chosen at three altitudes to study the variation of population structure characteristics. The results showed that with the increase of altitude, density of bamboo stands decreased, and asymmetric competition trended to be more intensive. While, diameter at breast height （DBH） enhanced greatly, and mean DBH increased 0.65 cm when elevation roused every 100 m. Significant influence of altitude on total height and height under the first branch of Moso bamboo were found, total height and height under the first branch of bamboo with the same DBH tended to increase with the increase of altitude. Furthermore, the influence of altitude on height under the first branch was greater than that on total height. With the increase of altitude, uniformity and evenness of bamboo forest decreased significantly. Thus, Moso bamboo stands at low, middle and high altitude respectively are suitable to be cultivated as shoots and seedling oriented stands, shoots oriented stands, shoots and timber oriented stands.