黄果厚壳桂人工林生长规律与林分更新特征分析

Growth law and stand regeneration characteristics of Cryptocarya concinna plantation

【目的】了解黄果厚壳桂人工林生长规律及林分更新特征,为其人工林栽培和生态公益林改造提供参考依据。【方法】采用树干解析法对36年生黄果厚壳桂人工林解析木胸径、树高及材积生长量进行测量,绘制生长曲线,分析其生长规律;采用样地调查法测量林下更新幼苗的密度、地径和苗高,并进行苗高分级,分析黄果厚壳桂人工林林分的更新特征。【结果】36年生黄果厚壳桂人工林胸径、树高和单株材积分别为18.82 cm、17.53 m和0.180 m^3。胸径和树高在第0~6年生长缓慢,胸径生长快速期在第6~11年,生长量为0.73~0.92 cm/年;树高生长快速期在第7~19年,生长量为0.60~0.97 m/年;材积生长较缓慢,36年生材积平均生长量仅0.005 m^3/年,最高连年生长量为0.012 m^3/年。人工林林下更新幼苗丰富,苗木平均密度为25.25株/m^2,其中以1~2龄苗木为主,占更新幼苗总数的82.43%,3龄及以上各龄级幼苗数量分别占更新幼苗总数的0.74%~3.50%。高度级在Ⅰ级和Ⅱ级(苗高20 cm以下)苗木占更新幼苗总数的81.20%,Ⅲ级及以上等级的幼苗数量占更新幼苗总数的0.74%~7.67%。苗龄3年以上或苗高20 cm以上苗木存活概率高。【结论】黄果厚壳桂人工林生长较缓慢,特别是材积生长慢及生长周期长,在一定程度上影响其作为常规用材林进行培育,但其人工林林下自然更新状况良好,林下苗木储备充足,可作为当前生态公益林营造和短周期轮伐树种生态公益改造的优良替代树种。

【Objective】In order to explore the characteristics of growth rules and stand regeneration of Cryptocarya concinna plantation,and to provide reference for plantation and transformation of ecological forest.【Method】The diameter at breast height(DBH),tree height and volume growth of 36 years old C.concinna plantation were measured by the method of trunk analysis,the growth curve was drawn,and the growth rule was analyzed.The density,ground diameter and height of regeneration seedlings were measured by the method of sample plot investigation,and the height grading of seedlings was carried out to analyze the regeneration characteristics of the C.concinna plantation.【Result】The DBH,tree height and volume of 36 years old C.concinna plantation were 18.82 cm,17.53 m and 0.180 m^3,respectively.DBH and tree height grew slowly in 0-6 years old,the rapid growth period of DBH was in 6-11 years old,and the growth amount was 0.73-0.92 cm/year,and the tree height growth was 0.60-0.97 m/year in 7-19 years old,which was fast.The volume growth was relatively slow,average growth of volume in 36 years old was only 0.005 m^3/year,and the maximum annual growth was 0.012 m^3/year.The plantation was rich in undergrowth regeneration seedlings,with an average seedling density of 25.25 plant/m^2,of which 1-2 years old seedlingswere dominant,accounting for 82.43% of the total regeneration seedlings,and 3 years old and above seedlings accounted for 0.74%-3.50% of the total.The number of seedlings inⅠlevel andⅡlevel seedlings height(seedlings under 20 cm height)was 81.20% in total,Ⅲlevel and above levels seedlings occupied 0.74%-7.67% of the total regeneration seedlings.The seedlings with the age above 3 years old or the height above 20 cm had a high survival rate.【Conclusion】The growth of C.concinna plantation is slow,especially the growth of volume,and the growth cycle is long,which affects its cultivation as a conventional timber forest.The natural regeneration of of C.concinna plantation is fine,provides sufficient seedlings storage,which can be a good alternative species for ecological forest and short rotation tree species ecological reconstruction.