基于可拓数据挖掘的天然异龄林起测直径研究

A Study on Minimum Measured Diameter of Natural Uneven-aged Forests Based on Extension Data Mining

从森林资源资产评估资产核查的角度出发,为准确表述林分质量、客观反映出材情况和有效降低外业工作量,运用可拓数据挖掘方法,选择林分蓄积量减幅、商品材出材量减幅以及株数减幅3个评价特征,计算不同起测直径水平下的关联函数值,分析提高起测直径带来的样地调查影响和变化规律,进而确定天然异龄林合理起测直径水平。结果表明,将天然异龄林起测直径从5 cm提高到9 cm,即将起测径阶从6径阶调整为10径阶,可以满足森林资源资产核查调查精度的要求。

With the purpose of accurately describing stand quality, objectively reflecting merchantable volume yielding and effectively reducing outside workload, by using Extension Data Mining three evaluation characteristics are reasonably determined, and the correlation function values under different minimum measured diameters are calculated in this paper. Then the paper investigates the direct impact and variation of sample plots＇ evaluation characteristics, brought by raising minimum measured diamete, to determine the reasonable level of minimum measured diameter for natural unevenaged forests. Finally the paper proposes to raise the minimum measured diameter of natural unevenaged forest from 5 cm to 9 cm, i.e. to adjust the diameter class from the diameter Class of 6 cm to the diameter class of 10 cm.