林下中草药种植活动对近成过熟杉木林单株材积生长的影响

Comprehensive effect of understory medicinal herb cultivation on individual volume growth in near-mature,mature and overmature Cunninghamia lanceolata forests

【目的】探究近成过熟杉木(Cunninghamia lanceolata)林中草药种植活动(包括相关的割灌除草、整地、施肥、日常抚育和林下作物生长等)对林木单株材积生长产生的综合影响。【方法】在浙西南景宁畲族自治县境内的大漈林场与草鱼塘林场近成过熟杉木人工林中,分别设置有3年林下种植中草药和没有林下种植的各10个样地,每个样地选择1株平均木进行树干解析,基于最近3年的材积连年生长量采用适应性强的线性模型方法,进行林下种植的影响评价。【结果】在同时考虑林木年龄、胸径、树高、密度、地位指数等因子的前提下,林下中草药种植活动对单株材积生长具有显著的促进作用。【结论】林下种植活动可显著促进近成过熟杉木林单株材积生长,有利于大径材培育,但这种促进作用受到林木年龄的制约。线性模型方法适用于情况复杂、无法对试验进行严格控制情况下的数据分析,但在小样本情况下使用线性模型方法需要在建模过程中对数据进行一系列是否满足条件的检验,对不满足要求的数据需采用一定方法进行调整。

【Objective】In the past,the understory planting was primarily conducted in young to middle-aged forests.However,with the advancement of public welfare forest development and the promotion of large-diameter timber cultivation,the issue of understory planting in mature stands has become an urgent research topic.This study aims to investigate the comprehensive effects of understory medicinal herb cultivation activities,including related shrubs cleaning up,land preparation,fertilization,routine care,and the growth of herbs,on the individual tree volume growth in mature Chinese fir(Cunninghamia lanceolata)forests.【Method】A total of 10 plots with understory planting of medicinal herbs and 10 plots without understory planting were established in mature Chinese fir plantations within Daji Forest Farm and Caoyu Pond Forest Farm,Jingning She Autonomous County,located in the southwestern part of Zhejiang Province.The medicinal herbs have been growing for a period of three years.One average tree from each plot was selected for wood analysis.The impact analysis of understory planting was conducted using a widely adaptable linear modeling approach,considering the annual growth measurements of volume,diameter,and height over the past three years.【Result】Under the simultaneous consideration of factors such as age,diameter at breast height,tree height,density,and site index,understory planting of medicinal herbs showed a significant promotional effect on individual tree volume growth.【Conclusion】With appropriate measures,understory planting can still significantly promote the volume growth of mature Chinese fir trees.However,this promotion is constrained by the age of the tree.The linear modeling approach is particularly suitable for analyzing data in situations where complexity exists and strict experimental control is not feasible.This method offers flexibility and provides reliable results.In small sample cases when using this method,it is necessary to perform a series of checks on the data to determine if the conditions are met in the course of modelling.Application of remedial measures to data that do not meet requirements.