论林木直径整化与材积误差

该文研究了林木直径整化与材积理论误差 ,结果表明 :①采用整化径阶计算的与用未整化的实测胸径值计算的林分调查因子相比 ,林分算术平均直径一般无误差 ,而林分平方平均直径和林分材积均产生正误差 ,直径整化后材积偏差的理论值应该为PV =(a2 12d2 )× 10 0 ;②对于服从大多数分布的连续变量 ,如正态分布或近似正态分布 ,采用按区间分组并把它的频率函数当作离散的来计算方差时 ,所得的分组方差 (σ2g)可以修正 ,以提高精度

Study on the stand volume error from the diameter rounding

As a basic theory in forest mensuration,the stand volume error from the diameter rounding was studied in this paper,and profound new ideas as following,①comparing the stand survey factors from the diameter rounding to those from the diameter without rounding,there is no error in the arithmetic average diameter in general,but positive errors in the stand square average diameter and stand volume,and the theoretical error value of stand volume is PV＝(a2/12d2)×100；②for the continuous variables following the most distributions such as normal distribution or approximate normal distribution,with its frequency function as discrete function,the variance(σ2g)from grouping data can be corrected to improve the precision.