摘要
随着近成过熟林等大龄林分的不断增加和幼中低龄林分的减少,大龄林分林下种植逐渐增多,但针对大龄林分林下种植对林木生长影响的研究较少,且存在新的研究难点.本文基于小样本线性模型方法,探讨大龄杉木Cunninghamia lanceolate 林下种植中草药对林木胸径生长的影响问题.2021年,在浙西南景宁畲族自治县境内的大际林场与草鱼塘林场大龄杉木人工林中设置了有 3年林下种植中草药和没有林下种植的样地各 10个,每个样地做 1株平均木解析木,基于解析木最近 3 年的胸径连年生长量,在对数据进行适用性检验、并对不符合要求的数据进行变换处理后,建立线性模型分析林下种植对胸径生长的影响.结果表明,对不满足线性要求的年龄进行变换消除非线性后的线性模型质量有明显提升,并在此基础上,发现林下中草药种植对胸径生长具有显著的促进作用,但这种作用受到林木年龄的影响和制约.线性模型方法适用于情况复杂、无法对实验进行严格控制情况下的数据分析,方法灵活,但在小样本情况下需要满足一系列条件,若不满足则必须先对数据进行处理以满足条件.
Abstract
In 2019,Polygonatum cyrtonema and Paris polyphylla were interplanted under mature Cunninghamia lanceolata plantations in Daji Forest Farm and Caoyutang Forest Farm in Jingning She Autonomous county,Zhejiang province.In 2021,ten sample plots with underplanting and ten ones without undersplanting were established,and one analytic wood was selected in each sample plot.Based on the consecutive annual diameter growth over the past three years and fitness tests,linear models were established to analyze the impact of underplanting on DBH growth of the plantation.The results indicated that replacement of plantation age increased the quality of the linear model after eliminating non-linearity.The observation showed that underplanting in the forest had a significant positive effect on DBH growth.
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