Study On Theories Of Forest Vegetation Recovery And Construction In Yanshan Mountain Area

Normal ecological functions of a degraded forest ecology system areseriously affected. Vegetation recovery and construction are effective means toenhance its structure and function, then studies on succession regulation, populationdynamics of plant communities, technologies and models of vegetation recovery andconstruction have important theoretical significance and realistic significance, asthey are the scientific basis in the process of vegetation recovery and construction.Taking Yanshan mountainous areas as study object, both permanent andtemperate sites are investigated. On the basis, ordination and quality classificationof plant communities, the population dynamics of forest plant communities, thedivision of site conditions, the technologies and models of vegetation recovery andconstruction were studied. The results are as follow:Based on the detrended corespendence analysis (DCA) and two-way indicativespecies analysis (TWINSPAN), it showed that there was certain regulation in thedistribution of plant communities in Yanshan Mountain, which was affected byecology gradients, and they were mainly determined by thermal and moisturegradients. In moisture gradients, from wetter to drier, the prevailing sequence wasBetula costata forest, Populus davidiana forest, Mongolian oak forest,Spiraeatrilobata L., Zizyphus jujuba Mill. Shrubs, Fitex negundo shrubs-meadowwith Warmwood and Carex as the dominant species. In thermal gradients, from coldto warm, the prevailing sequence was meadow-Betula costata forest, Larix principis,ruppechtii, Betula platyphylla forest, Mongolian oak forest, Broad-leavedcommunity with Prunus sibirica as the dominant species in mid-low mountain,Spiraeatrilobata L.-Corylus shrubs. The DCA nonhierachical ordination showed thevegetation succession of Yanshan Mountain exits 4 polar points and 1 centre. The 1center was an area in which Quercus mongolica, Populus davidiana and Pinustabulaeformis were dominant species. Four polar points were 4 succession trends indifferent ecology gradients. Form hot and dry to cold and wit, the successionadvanced toward Betula platyphylla and Betula costata as dominant species withLarix principi-rupprechtii and Picea asperata as associated plant. Form cold and wit tohot and dry, the succession advanced toward shrub which dominated by Zixyphus jujbavar spinosus and Vitex negundo var. heterophylla. Form cold and dry to hot and wit, thesuccession advanced toward shrub which dominated by Quercus wutaishanica and Corylusmandshurica associated by Juglans mandshurica. Form hot and wit to cold and dry, the succession advanced toward weed which dominated by Artemisia sieversiana and Carexsubpediformis. Low-mountain shrubs can grow well in the center. The DCA value washighly relative to environment factors and geographic mathematical model. Themathematical models of climate factors with geography coordinate and the value ofDCA ordination with environment factors had been established. Applying thesemodels, the types and distribution community could be forecasted and judged.During the early 15 years in secondary succession began after clear felling, inclear felling vegetation of natural Mongolian oak community, manmade Populusdavidiana community and Larix principis-ruppechtii community, the secondarysuccession had a similar growth and decline process in the aspect of species numbergetting bigger, but there were differences in clear felling vegetation between naturalforests and manmade forests. In the clear felling vegetation of natural forest, therewere frequent species substitution at the beginning, and then being slower, In theclear felling vegetation of manmade forests, there was a frequent speciessubstitution in the evening of 15 years. In different succession phase, the dynamicsof arbor, shrubbery and herbs were different, but their population densities weresame in the process of being larger first and then being smaller. The important valuesof shrub and herbs were fluctuant because of the impacted by the crown density ofarbor and mutual effects between shrubs. The important values of shrubs werepolarized. The important value of shrubs that had weaker competitive power fellgradually. By contraries, the important value of shrubs that had stronger competitivepower and bigger niche breadth rose gradually. The important value of lightherbaceous was climbing early and falling later. Shade-requiring herbaceous wasdominant in the evening of succession and their importance value rose gradually.In different clear felling vegetation, diversity index fluctuated differently. Inclear felling vegetation of natural Mongolian oak community, diversity index ofarbors, shrubs and herbs were high, and they keep on getting higher as successionwas going on. In clear felling vegetation of manmade Populus davidiana communityand Larix principis-ruppechtii community, their diversity indexes were lower, withfluctuations of being higher in the middle and decline afterwards. After clear felling,the diversity index of arbor rose and kept on. The diversity indexes of light shrubsand light herbs rose early and felling later. The diversity indexes of shade-requiringshrubs and herbs rose gradually. Community species diversity index dynamics andits fluctuation extend of arbors, shrubs and herbs were similar to those of singleherbs. Pielou evenness index of all communities shared the same dynamics withspecies diversity index. During the early 15 years in secondary succession, theaggregate index of arbor, shrubs and herbs plants were in the process of gettinghigher and then declined as the succession development. The distribution pattern of all species developed form accumulation to random.Soil thickness, altitude, slope aspect, gravel content, gradient and humusthickness were the 6 main site factors in Yanshan Mountain. According to the 6factors, there were 9 types and 22 sub-types of site condition. As to different siteconditions, the thoughts of vegetations recovery and construction were put forward.In this paper, the succession rule, trend and status quo were analyzed, 6principles, 4 demands and 3 means of vegetation recover and construction were putforwards. It pointed out that in Yanshan Mountain areas, for degraded naturalsecondary forest, the thoughts, technique and models had been put forward. Thetypical reconstruction models of forest vegetation from natural shrubs had beensummarized. The reconstruction technique system of manmade forest vegetation hadbeen put forward and 120 species plants that can grow well in Yanshan Mountainareas had been selected. Based on the site conditions and economic status, 5successful manmade vegetation construction models had been built, which were soiland water conservation type, difficult site condition type, aerial seeding in mid-lowmountain type, water sources conservation type and eco-economy type.