【作者】 王乃江；

【导师】 张文辉；

【作者基本信息】 西北农林科技大学 ， 森林培育学， 2008， 博士

【摘要】 陕西省黄龙林区位于黄土高原腹地，为以油松、辽东栎和白桦等地带性森林植被为主的落叶阔叶林区，是陕西省黄土高原地区森林集中分布区和绿色生态屏障之一，在控制黄土高原水土流失、生态环境建设和工农业生产中具有战略地位。和全国其它地区一样，自1998年实施“天然林资源保护”和“退耕还林”工程以来，黄龙林区停止了任何形式的森林采伐和抚育作业。森林的禁伐，使森林以封山育林的形式完全被保护起来，在森林资源保护方面取得了举世瞩目的成就。但森林抚育工作基本停滞，随之带来森林自然枯死、病虫害大面积发生等一系列经营问题，森林资源不能得到合理的利用，造成了资源的严重浪费。同时，对于天然林的禁伐效果，一直成为人们争论的问题，甚至有人提出禁伐不是解决森林保护问题的最根本的办法。根据黄土高原森林和植被建设以水土保持效益和生态保障为主、兼顾经济效益的基本定位和原则，本研究针对黄土高原现有的森林现状和经营水平，从森林主要种群的种间联结性、林地生产力、森林近自然经营技术的应用、群落生态功能和演替趋势等不同方面，应用种群生态和群落生态学的基本理论，采用建立数学模型的方法，对该地区过去近50年来的森林经营效果进行了综合评价和科学研究，系统分析了该地区天然林的特征和恢复机理，为采伐解禁和天然林保护工程以后的森林经营提出了建设性建议。主要研究结果如下：1．陕西黄龙林区天然次生林森林群落可分为乔木、灌木和草本3个结构层次，主要种群的种间联结性总体上都表现为正关联，乔木层和灌木层多物种间总体关联较为显著；草本层总体关联不显著，种间无关联的成分较多。在乔木层，主要种群种间关联不明显，表现出相互独立的特点。辽东栎和油松，油松和茶条槭，茶条槭和白桦，杜梨与辽东栎、油松、茶条槭、白桦等7个种对存在一定正关联。辽东栎与漆树，茶条槭与山定子，山杨与榆树、山定子，白桦与山杏、漆树等6个种对存在一定副关联。山杏和榆树、柳树无关联，独立性强。灌木层中，南蛇藤和悬钩子、水栒子和红瑞木、胡枝子和华北丁香之间存在极显著的正联结；华北绣线菊和野葡萄、冻绿和栓翅卫矛、南蛇藤和野葡萄、南蛇藤和葱皮忍冬之间存在显著的正联结。草本层种间联结较为松散，种对间无关联的种对数多达21个。另外，在进行种间联结性研究时，不要根据一个指标就得出结论，最好多个指标配合使用来说明种间联结程度。2．应用灰色关联度分析方法，可以合理地评价和计算森林的近自然度，解决森林近自然经营理论应用中的关键技术问题。研究证明，黄龙地区不同森林类型的近自然度不同，其自然化程度和群落特征有明显差异。主要森林类型的近自然度依次为油松林0．9462、辽东栎0．9025、白桦林0．8790、松栎林0．8747、松桦林0．7142、栎桦林0．8193。油松林近自然度最高，初步认为油松林的自然化程度最好，辽东栎林、白桦林、松栎林和栎桦林基本一致，松桦林最小。油松林和辽东栎林属于该地区的顶极森林群落，白桦林、松栎林和栎桦林属于演替过渡时期的森林类型，松桦林是向顶级过渡但不很稳定的森林类型。3．可以从生态功能、演替趋势、林地生产力和人为干扰等四个方面，采用物种多样性指数、人为干扰、土壤养分、物种均匀度、优势种群幼龄数量比、林分蓄积量、森林总郁闭度、放牧情况、幼苗数量和林下灌木草本生物量等十项指标，建立了天然林质量评价模型，确立质量评价指标体系。森林质量评价结果为油松林最好，辽东栎林、栎桦林和白桦林较好，松桦林和松栎林较差。4．黄龙林区森林生产力可以主要用林分蓄积量、林下灌木和草本生物量等指标来表示。油松、辽东栎、白桦林、松桦林、松栎林和栎桦林等六种主要森林类型的林分蓄积量分别为113．09 m~3．hm~2、51．07 m~3．hm~2、61．08 m~3·hm~2、92．72 m~3·hm~2、104．37 m~3·hm~2和40．24 m~3·hm~2。油松林的蓄积量最大，以油松为主要优势树种的林分，蓄积量明显大于其它森林类型。在显著水平P＜0．05条件下，油松林、松桦林和松栎林的蓄积量无明显差异，辽东栎和栎桦林差异不明显，白桦林明显不同于其它森林类型。黄龙林区林下灌木分布较均匀，生物量远远大于草本。林下灌木生物量平均为4．987t／hm~2，草本为0．755t／hm~2。在同一森林类型中，林下灌木生物量在干、枝、叶根等营养器官中的分配有一定的差异，但不同森林类型差异不明显。在辽东栎、松栎林和白桦林中，灌木生物量较高，栎桦林、油松林和松桦林相对较低，油松林和栎桦林基本保持一致。5．从过去50年来，多种森林经营方式的作业效果的比较来看，油松林、松栎林和松桦林等以油松为优势木的林分定株间伐、综合抚育效果好或较好，二次抚育效果差；辽东栎和栎桦林封育效果好，低产林改造和带状间伐效果差；白桦林封育效果好，低产林改造效果中等。另外，辽东栎和白桦林低产林改造并没有取得理想的经营效果，带状间伐不太适合辽东栎林的经营和抚育。所有森林类型的封育效果较为明显，封育后林分质量明显好转。6．在陕西省黄龙山林业局蔡家川林场应用森林近自然经营理论，采用目标树单株木森林经营体系，建立了油松林和松栎林四块“森林近自然经营试验示范林”(40hm~2)。对示范林进行了林木分类和标记，并实施采伐作业。采伐后(2年)的林分稳定性良好，林分年龄结构和空间结构更加合理，优势木比例和0～20cm土壤速效N含量明显增加。虽然林内小生境发生了一定的变化，但物种多样性变化不明显。油松林下灌木和草本生物量比松栎林略有增加。在陕西省黄龙山林区，森林近自然经营理论在森林经营中的应用效果明显，这种以目标树单株木经营为核心内容的近自然经营理论和技术可以在黄土高原退化天然林和人工纯林的近自然化改造中加以推广和应用。该研究是对黄土高原森林区天然林的一次系统研究，对黄土高原脆弱生态环境下退化天然森林的保护、植被建设、生态环境修复具有重要的理论价值，对制定科学的森林经营方案和对策具有重要的战略意义和应用价值。更多还原

【Abstract】 Huanglong mountains,a typical wooded regions,located in southeast Yah’an city,Shannxi province,China,and played important part in soil and water conservation,ecologicalenvironment,agriculture and industry on Loess Plateau.This wooded regions belonged toconiferous and broad-leafed forest vegetation containing some important species such as Pinustabulaeformis,Quercus wutaishanica and Betula platyphylla.Since 1998,the projection ofNatural forest protection and artificial forests by grain for green had been administed in China.Becouse of forbidding to cut all kinds of stands,the forest management was influenced,andthese policies leaded to a series of bad result such as outbreaks of diseases and insect pests.Thegoverment and scholars in growing numbes were beginning to complain the forest recourceswas wasted and not been utilized rationally.People had been disputing the result of forbiddingto cut forest although it’s purpose was to protect forest.According to the principles of soil and water conversation,ecological and economicbenefit priority,on the basis of the current situation of forest resources and management,usedthe thoeries of population,community and the model of forest assessment,this paperanalysised the effect of the forest management in past 50 years on Loess Plateau.These resultsofreseach were as follows:1.The community of natural forest can be divided into three layers,such as tree,shrub andherb.The result showed that the interspecific association of these three layers were positive ingeneral,but the species in herb layer did not show a significant positive association.Thedominant populations existed independently in tree layer,but the interapecific associatin was atno siginificant level,and x² values implied that seven pairs of pecies such as Quercuswutaishanica and Pinus tabulaefomis,Pinus tabulaefomis and Acer ginnal,Acer ginnal andBetula platyphylla,Pyrus betulaefolia and Quercus wutaishanica,Pinus tabulaefomis,Acerginnal,Betula platyphylla had close relationship.The several indicators used together was aeffective way to measure the interspecific association.2.Using the method of gray relational analysis,we can carry out the estimation of theforest nature closeness,and resolve the key problems of applicatin of the thoery ofclose-to-nature forest mangement in China.This studies demonstrated that the different forestcommunity had the fifferent nature closeness,and evry forest community showed thesignificant diffirance in natral state and characteristics of community.these gray correlationdegree were separately 1.143 for P.tabulaefomis,1.085 for Q.wutaishanica,0.849 for B. platyphylla,0.893 for P.orientalis,0.789 for P.davidiana.It was estimated that P.tabulaefomis and Q.wutaishanica was the best forest types which had the higher graycorrelation degree and belonged to the climax community in Huanglong forest region,on thecontrary,P.davidiana was not stable.The others was developing to the climax community.3.The model of forest quality evaluation and the index system of assessment for forestquality was setted up.The research believed that the forest quality can be appraised byecological functions,the tendency of forest succession of community,the productivity ofwoodland,jamming,et al.The results indicated that the stand quality ofP.tabulaefomis was thebest,Q.wutaishannica and B.platyphylla were the better,and their mixed forest were theworst.4.The stocking volumn,biomass of shrub and herb in the undergrowth can be used toexpress the produtivity of forest.Stocking volumn of these xis types of forest were respectively113.09,51.07,61.08,92.72,104.37,and 40.24 m³·hm².The stocking volumn of p.tabulaeformis and it’s mixed stand was the biggest,and there were significant fifferancebetween these six types of forest.The shrub occursed wildly and evenly in the stands of all kind of forest.The biomass ofshrub of 4.987t·hm^-2 was far outweigh the herb of 0.755t·hm^-2.The bimass of shrub wasdistributed in the plant organs such as trunks,branches,leaves and roots.5.Comparsing of the different forest operation programes in the past 50 yeas,the studyindicated that the effect of thinning was the best for p,tabulaeformis,all cutting was the worst.That fenced off for afforestation was the best for Q.wutaishannic and B.platyphylla.Thequality of forest fenced off for afforestation had been improving gradually.6.Four demonstration stands,40hm²,containing the thoery of closed-to-nature forest,were established in Huanglong forest region.In two yaers later,these stands that interferencetrees were cut were stable,the structure of these stands were reasonable than before,theproportion of domination tree and the content of rapidly available P in the soil of 0～20cm wasbeing increasing.Although the site of forest changed,diversity did not vary wildly.In brief,theeffect of application of close-to-nature forest management was obvious,and it illustrated agood prospect of application and extension of this thoery.This research was a systematized study on natural forest on Loess Plateau.Its findingsprovided a scientific foundation for natural forest protection,vegetation recovery and rationalutilization of land.更多还原