坡度和坡位对巨龙竹发笋成竹及林下植被多样性的影响

Effects of slope degree and slope position on shoot growth and undergrowth diversity of Dendrocalamus sinicus

以滇西南巨龙竹为研究对象,采用随机区组试验设计,分析坡度(陡坡、斜坡、缓坡)和坡位(上坡、下坡)对巨龙竹发笋成竹及林下植被多样性的影响.结果表明:坡度显著影响巨龙竹发笋成竹及林下植被多样性,坡位影响不显著,但2者交互效应影响显著.同一坡位,随坡度增加,巨龙竹发笋数、发笋率、成竹数、退笋数和退笋率趋于增大,成竹率趋于减小,成竹胸径呈先减小后增大的变化趋势,层间植被和灌木层植被多样性呈先升高后降低的变化趋势,而草本层植被多样性呈升高趋势;同一坡度,巨龙竹发笋成竹特征总体上下坡优于上坡、林下植被多样性特征总体上上坡优于下坡.其中,试验处理组合2号即陡坡下坡位对巨龙竹发笋成竹及林下植被多样性特征影响的综合测评得分最高.因此,建议以陡坡下坡位作为巨龙竹扩繁栽植点的首选,但需注意栽后培土、疏笋等,同时应适当清除灌木植被和保留草本及匍匐藤本植被.

A randomized block experiment was designed to study effects of slope degree(steep,moderate and gentle slope)and slope position(uphill and downhill)on shooting growth and undergrowth diversity of Dendrocalamus sinicus in southwest Yunnan Province.The results showed that slope degree and the interaction between slope degree and slope position had significant effects on the shooting growth and undergrowth diversity of D.sinicus,while the effect of slope position alone was minor.At the same slope posi-tion,shoot emergence number and emergence ratio,grown bamboo number,degenerated shoot number and degenerated shoot ratio rose along with increasing slope degree;while grown bamboo ratio decreased and young bamboo diameter decreased firstly and then increased.The vegetation diversity of shrub layer and inter-layer increased firstly and then decreased while the vegetation diversity of herb layer saw an uprising trend mainly.At the same slope degree,overall growth properties of shoots on the downhill slope were su-perior than those on the uphill slope;undergrowth diversity properties were higher than those on the downhill slope.Among all the experimental setups,treatment No.2(steep slope+downhill slope)was the most effective in promoting shoot growth and undergrowth diversity with the highest evaluation score,indicating that steep-downhill slope was the optimum choice when selecting planting site for the propagation of D.sinicus.Meanwhile,earthing up and thinning bamboo shoots are recommended after planting seedlings;shrubs should be properly weeded with herbs and lianas vegetation well preserved.