太行山低质低效林判定标准

低质低效林是指进展演替的初期或逆行演替的结果，森林合理的结构尚未形成或遭到破坏，林木个体质量低劣，自然生态效益及社会经济效益低下的林分。判定低质低效林的依据是林分的结构、林木个体质量、密度和郁闭度、灌木林结构和功能。残次林是林分逆行演替的结果。劣质林主要是人为破坏加上萌生繁殖造成主干质量低劣。低密林是处于进展演替过程初期尚未达到一定密度或由于人为过量采伐致使密度降低，前者林木质量尚好，后者则为砍伐剩余的劣质林木。低灌林与低密林的形成类似也分两种情形，前者一般立地质量低劣，后者则由于由乔木或乔灌混交林退化而来，立地尚好，植被恢复容易。

The Criterion of Low quality and benefit Forests in Taihang Mt.

Low quality and benefit Forest (LQBF) is that which is either at the initial period of progressive succession or as the result of regressive succession,in which either the rational structure hasn't built up or has been destroyed,and tree's individual quality and/or ecological and economical benefit are poor.Forest structure,individual quality,tree density and crown density,and structure and function of brush forest are used to construct a criterion to the LQBF.LQBF is then divided into 4 types,remnant forest,inferior forest,low density forest,and poor brush forest.Remnant forest is as a result of forest regressive succession.Inferior forest's characteristic is inferior in stem quality that is due to the human's disrupting and multi generation sprouting.There are two circumstances in low density forest's formation.In the fist circumstance,as in the initial period of progressive succession the forest is not yet closed,but good in tree quality.In the second circumstance,the forest density has dropped down because over cutting,while the quality of the residual trees has dropped either.The same is true of the formation of poor brush forest in that there are two circumstances,too.The brush forest either has been developing on the poor site with undeveloped structure,or degenerated from a high forest or a tree brush mixed forest on good site,where the vegetation would be recovered easily.