毛竹碳汇林栽植方式在成林初期对空间分布格局变化特征的影响

摘要

毛竹Phyllostachys edulis林空间结构是毛竹生长过程的重要因子,是提高竹林质量,优化经营水平的重要参考依据.利用聚集指数和Ripley's K(d)函数,分析从2009-2013年毛竹碳汇林成林初期空间分布格局年际变化特征及匀栽、 丛栽栽植方式对分布格局的影响.结果表明:①在5 a造林年限间,2种栽植方式下的新竹与活立竹的空间分布格局均呈聚集分布;②丛栽栽植毛竹林新竹聚集指数变动范围为0.38~0.76,活立竹聚集指数变动范围为0.45~0.60;匀栽栽植毛竹林新竹聚集指数变动范围为0.18~0.65,活立竹聚集指数变动范围为0.18~0.52;③聚集指数与活立竹株数间存在较强的相关性,匀栽毛竹林活立竹株数(x)与聚集指数(y)拟合方程为y=0.1037x0.4193,R2=0.9379;丛栽毛竹林活立竹株数(x)与聚集指数(y)符合二次方程:y=0.00004x2-0.0027x+0.501,R2=0.9856;④新造毛竹碳汇林在成林过程中存在不同尺度距离下的团状聚集分布;⑤栽植方式对立竹株数和分布格局影响明显.%Spatial structure in a moso bamboo (Phyllostachys edulis) stand is an important factor in its growing process. To analyze the influence of interannual variation characteristics of spatial patterns having different planting patterns in the early stage of moso bamboo stands used as carbon sinks, an aggregation index and Rip-ley's K(d) function were applied from 2009 to 2013, and results were fitted with regression equations. Results showed 1) spatial patterns of new moso bamboo and established moso bamboo with an aggregated distribution pattern after five years of afforestation. 2) The aggregation index in group-planted moso bamboo stands for new moso bamboo was from 0.38 to 0.76 and for established moso bamboo was from 0.45 to 0.60; for uniformly planted moso bamboo stands, the aggregation index for new moso bamboo was from 0.18 to 0.65, and the estab-lished moso bamboo stand was from 0.18 to 0.52. 3) A strong relationship was found between the aggregation index of an established stand of moso bamboo (y) and culm number (x). For a uniformly planted moso bamboo stand, the fitted regression equation was y = 0.1037x0.4193, R2 = 0.9379; and for group-planted moso bamboo stands it was y = 0.00004x2 - 0.0027x + 0.501, R2 = 0.9856. 4) In the process of forest establishment, new moso bamboo carbon sink stands existed as an agglomerate distribution for different distance scales. 5) Thus, the cultivation mode influenced the moso bamboo stand's culm number and spatial distribution pattern.