Study On Biomass Compositions Of Principal Vegetations And Their Relationships In The Dagou Valley Of The Upper Minjiang River

The second vegetation is important position in forest ecosystem. It has the core meanings for studying biomass. The second vegetation is above half in forestry in our country. The rate will be increasing with the development of period. So studying it and cultivating it is importance for elevating/increasing biomass and productivity.This research of elevator is between 1500m and 4100m in the Dagou Valley of the upper Minjiang River in Maoxian County Sichuan province. The field is the centre of biodiversity inChina in world. Recent years, human actions result in serious receding/degeneracy-the coverof forestry has decreased from 30% in 1950s to 18% in 1980s. Recently, there are amount of fields become cut-clear and receding shrub forestry. Ecological environment become deterioration increasingly. Since 1980s Chengdu Institution of Biology and local government have carried out a lot of experiments of restoration. Diverse vegetations of restoration have showed some ecological effects for 20 years, while ecological courses are very complicated. Which restoration model is more advantage to ecosystem? It is significant to restoration work and popularizing restoration model. The biomass/productivity of vegetation populations is the base to study on forest productivity and on nutrition trends/state of population. Since IBP from 1960s, studying on biomass/productivity has been an important direction in ecological researches. And it becomes one of the most important indexes to evaluate whether ecosystem of restoration is success or not.This paper study on the second vegetation including artificial forests, hybrid shrub populations, Sinarundi-naria nitida(Mitford)nakai populations, Rhododendron populations and Birch forests, and on their components of biomass and contributions. It will offer the theoretical and practical base to evaluate artificial restoration and natural restoration.This paper chiefly divided into five parts, the first study is the components of biomass and structural biomass in artificial forests. Expound upon the relationship between biomass and environmental factors. The conclusions show that, biomass allocation of arbor is following: trunk > branch > leaf > root > bark/fruit except P. Tabulaeformis/Chinese pine; elevator and aspects/direction are the principal influential factors, but slope gradient is not; density significantly relate to biomass. In the same time, it refers that, arbor density is significant influence on shrub and herb in arbor forests.The second part is to study on the components of biomass and its contribution patterns in shrub forests. The results show that: 1) hybrid shrub populations biomass is low, human disturbances are serious, biodiversity is riches, and rapid restoration; 2) Sinarundi-naria nitida(Mitford)nakai populations /community biomass is middle, their distribution is clumped, they are vitality, their roots are flourishing, and they are advantageous/beneficial to water and soil conservation; 3) Contribution areas of Rhododendron populations/community are wide, they are density at high elevator ranges in this field, biomasses are large, their average biomass is maximum in shrub communities in this valley (about 197.07t/ha), human disturbances are trivial, and locate the prevailing climax state, but their restoration period are long.The third part is to study on the components of biomass and its contribution patterns in Birch forests. The results show that: 1) arbor density is sparse, but individuals are large, average biomass is high (357.21t/ha); 2) Birch forests have complex layers (usually including arbor layer, large shrub layer, short shrub layer, and herb layer), and it displayed a pattern of biomass, that is, arbor> large shrub > short shrub > herb/litter/moss; 3) under the Birch the vegetations are abundant and diversity, the cover of herb/litter/ moss is high (usu. >90%), and so on; 4) The same with artificial forests is that the principal influential factors are elevator and aspects, and the relationship between density and biomass is significant.The fourth part is to compare the restoration patterns and to evaluate the effects of restoration patterns. The conclusion is that, artificial forests pattern possess the rapid restoration, but their system structural layer is simple, and lack stability; Natural restoration is low speed, their restoration period is long, but their structural layer is complicated and biodiversity is high, and their ecosystem is stability.The fifth part have systematically and comprehensively/overall concluded and analyzed the former parts; and put forward many practical restoration measurement suggestions. At the process of restoration, it refers to that, not only adopt a simple arbor restoration model, but also adopt shrub and herb restoration as its auxiliary/complementary measurements for elevating biomass/products and increasing the stability in restoration ecosystems.