天然林在原始状态下基本都是异龄林。天然林的成熟是林分中个体林木的相继成熟,成熟一株采一株是天然林采伐的本质。历史上对天然林的采伐方式基本上都是不科学或不尽科学的。唯有通过林木资源投入、产出和产出效率的比较所确定的树种材种和经济二种成熟径阶为依据的限径择伐,实现了每株被伐木都是最高产出效率的体现,并将保留林分推向最大生长量和最高生产力的极至状态,从而实现最优的经营效果。 Natural forests in the original state are basically the same age forest. The maturity of natural forest is the individual tree in the forest have been mature, a plant is a natural maturity of the nature of harvesting. Historically, harvesting of natural forests is basically unscientific or unscientific. Only through the selection of the tree species and the economy based on the two kinds of mature orders based on the comparison of forest resource input, output and output efficiency, the maximum output efficiency of each plant is realized , And will retain the stand to the maximum growth and maximum productivity of the state, in order to achieve the best operating results.