摘要
通过对浙江、江西、湖南等省的丰产林(Ⅰ)、中产林(Ⅱ)、低产林(Ⅲ)三种类型毛竹林的大量调查,计算得出如下结果:①在同一毛竹林类型中竹林胸径的变异度最小,蓄积量次之,新竹产量变异度最大。②同一调查因子中毛竹林类型不同变异度不同,Ⅰ类竹林的变异度最小,Ⅲ类竹林变异度最大。同一调查因子和同一毛竹林类型中变异度也各不相同。因此毛竹林调查面积应根据不同的竹林类型和不同的调查目的来确定。如进行资源或蓄积量调查,适宜的竹林面积Ⅰ类竹林应是400m^2,Ⅱ、Ⅲ类竹林应为500—600m^2。③毛竹林虽有很强的边际效应,但计算表明,毛竹林样地的形状不一定拘于正方形,可因地制宜设置长方形或正方形。④通过对毛竹林蓄积量或产量的几种常用计算方法的误差率对比,提出用平方平均胸径来求算蓄积量或产量是较简便又可靠的方法。同时对毛竹林蓄积量或产量计算中胸径与眉径的换算规律进行了探讨。
The variation of basic investigation factors of bamboo stands such as volume, total weight of newly born bamboo individuals per year, density and d. b. h. (diameter breast height) are varied, with the least coefficient of variation in d. b. h. and largest in total weight of newly born bamboo individuals per year. Less variation was found in bamboo stands of grade I i. e. stand with high yield and more in stands of grade Ⅲ i. e. stand with low yield. For the measurement of total weight of newly born bamboo individuals per year, the size of sample plot for stand of grade I suggested is about 500 m2 and for that of grade Ⅱ and Ⅲ 600-800 m2 generally. Neither the shape of sample plot nor the location of the rectangular sample plot was found with apparent effect on experimental error.For the evaluation of volume or yield of bamboo stands, the simplest and fastest method found was to multiply the total number of bamboo individuals by the mean weight of bamboo individuals calculated from the mean value of the squared diameter in the sample plot. The average ratio of the deviation calculated by this method from real yield to real yield was less than 0.1%.For sample plots only with data of diameter of brow height (D1), it is possible to calculate the diameter breast height (D) from D1 using following formulae:D=0.02057 + 1.01767 D1 for stands of gradeI ,D = 0.16138+ 1.00546 D1 for stands of grade Ⅱ and D= 0.04155 + 1.01873 D1 for stands of grade Ⅲ.
出处
《林业科学研究》
CSCD
北大核心
1989年第3期268-276,共9页
Forest Research
关键词
毛竹林
样地设置
调查法
蓄积量
bamboo stands
arrangement of sample plot
investigation method
volume
yield
