Study On The Designing Of Forest Development Types For Typical Vegetation Types In Xi'shan Region, Beijing, China

As one of the complicated ecosystems on the land,forest is an important safeguard to ecological equilibrium.With social developement,forest is more and more disturbed by human actions,virgin forest that is not disturbed is less all over the world.It is very important that forest dynamic is rational planning and designing.Forest planning or forest designing is arm at a positive,steady and healthy forest structure,not a negative,fragile and deteriorative forest status. Forest dynamic is foreseeable in a certain extent,on which rational forest designing is put forward in order to make forest multiple function bring into play.Forest development type designing(FDTD) is a new object-oriented planning of forest dynamic,current become in to action in some countries from Europe,and this designing is strictly follow the forest succession theory,adequately utilize the character of potential natural vegetation(PNV) and take the possibility of practice into consideration.As the result of those features,forest development type designing become one of important parts of close-to-nature forest management(CNFM),one of modern forestry management mode.According to forest succession principle,CNFM theory and PNV of Xi'shan region,Bejing, in this article,after invensy,analysis and forest development and potential nature vegetation of typical vegetation types in the Xi'shan region,Beijing,Forest development type(FDT) is named with dominance tree species,stand structure,main forest function and site quality so on,and FDT is designed for four typical forest types such as Pinus tabulaeformis Carr.forest(Chinese pine forest),Platycladus orientalis Franco forest(arborvitae forest),Quercus variabilis Bl. forest(cork oak forest ) and Robinia pseudoacacia L.forest(silver chain forest) in the future of 30-50a and assessed the close-to-natureness and the degree of stand dominance of four forest development types. (1) According to horizontal stand structure,vertical stand structure,regenezation level of stand,crown competition factor,stand average competition index and individual growth process so on,58 plots of four forest types is divided different forest development stages and every typical forest type is designed object-oriented FDT,the designed results are as follow:17 Chinese pine forest plots are dividied into 5 development stages such as the competition growth stage,the stage between of competition growth and qualification selection stage,the qualification selection stage,the stage between of qualification selection and close-to-nature stage,the close-to-nature stage.And 3 object-oriented FDTs are designed such as uneven aged & multiple levels Chinese pine forest,Chinese pine & cork oak mixed forest and cork oak & Chinese pine mixed forest.19 arborvitae forest plots are dividied into 3 development stages such as the competition growth stage,the stage between of competition growth and qualification selection stage,the qualification selection stage,and then 3 object-oriented FDTs are designed such as Platycladus orientalis Franco & Ailanthus altissima Swingle(or Koelreueria paniculata Laxm.) mixed forest,arborvitae & cork oak mixed forest and arborvitae seed stand.16 cork oak forest plots are divided into 3 development stages such as the competition growth stage,the stage between of competition growth and qualification selection stage,the qualification selection stage,and one object-oriented FDT is designed such as uneven aged & multiple levels cork oak forest.6 silver chain forest plots are classified into 2 forest types,one is a deteriorative forest,and another is a positive forest,accordingly,2 object-oriented FDTs are designed such as Acer truncatum Bunge & Robinia pseudoacacia L.& Ailanthus altissima Swingle mixed landscape forest and silver chain & cork oak mixed forest.(2) Diameter hierarchy index,stand stock,regeneration number,Shannon-Wiener index of tree species of understory,Pielou evenness,decompression of ground-litter level,and climax adepatation value are seven basic indictors to close-natureness,and these seven indictors's value are 0.0812,0.2037,0.09,0.0543,0.1831,0.1373,0.2504 in turn by the method of Analytic Hierarchy Process(AHP),and then the ciose-natureness of Chinese pine forest,arborvitae forest and cork oak forest by AHP & Grey Correlation Analysis are as follow:The close-natureness values of 5 stages of Chinese pine forest are 0.3423,0.5135,0.5358, 0.56,0.9443 in turn,those of 3 stages of arborvitae forest are 0.3791,0.6523,0.7882 in turn, those of 3 stages of cork oak forest are 0.514,0.6416,0.7397 in turn.(3) According to Kraft tree classification system,the trees are classified into 6 types such as super-dominance tree,dominance tree,co-dominance tree,suppered tree,dying tree and dead tree and so on;Chinese pine forest,cork oak forest and silver chain forest are assessed in tree dominance hierarchy diversity,distribution of tree dominance hierarchy and stand dominance degree as well.The result of assessment is as follow:The tree dominance hierarchy diversity of Chinese pine forest,cork oak forest and silver chain forest are 8.491,11.36 and 10.651;super-dominance density of Chinese pine forest is up to 481 n/hm~2,and the highest dominance density is dominance tree and co-dominance tree in cork oak forest,which in silver chain forest the dominace density of dying tree and dead tree are 116 and 53 n/hm~2 in turn;the basal area of super-dominance tree in Chinese pine forest is 10.16m~2/hm~2,higher than that of other two forest types,which in cork oak forest the basal area of dominance tree,co-dominance tree and suppered tree are 6.51 m~2/hm~2,2.43 m~2/hm~2 and 3.1 m~2/hm~2,higher than that of other two forest types;The stand dominance degree of Chinese pine forest,cork oak forest and silver chain forest are 117,69 and 60.6 in turn.