Mechanism Of Water Resources Conservation And Recharge Of Forest And Its Ecological Function Value Evaluation In Jinyun Mountain

Jinyun Mountain, lying in tail end of Three Gorge reservoir area, is a spontaneousness laboratory to study systemly water resources conservation and recharge function of forest because it has integrated coenotype of subtropical broad leaved evergreen forest and reflects natural background of tropical forest ecosystem in central asia to a certain degree. On the base of fully study on rainfall characteristics of Jinyun Mountain area 4 familiar types of forest, namely mixed broadleaf-conifer forest, broad-leaf forest, Phyllostachys pupescens forest, and shrub forest had been chosen as subject investigated to study water resources conservation and recharge mechanism of different forest types in Jinyun Mountain and evaluate its value of ecological function by the means of grey correlation method, regression method, shadow price method, break-even cost method, and analogism. Then, evaluating indicator system of forestry water resources conservation and recharge had been established making use of Analytical Hierarchy Process(AHP) and fuzzing mathematics. The research conclusion not only contributes to construction project of ecological environment and Three Gorges project in the Yangtze Valley and but also has of far reaching importance to comprehensive amelioration of ecological environment and sustainable development of social economic in this region. Furthmore, value evaluation of forestry water resources conservation and recharge can offer reference to standardization of ecological compensation policy in this region. Concretion conclusion is below:1) There was a obvious linear relationship between forest intrinsic soaking rain and rainfall amount and rainfall duration of 4-type of forest; whereas storey interception had power function relation with increase of the corresponding period, contrastly, leaf canopy entrap rate decreased with increase of rainfall amount. Maximum moisture capacity of both that of branches and leaves of 4-type of forest in Jinyun Mountain was 2.34 - 5.23 t/hm~2 : maximum moisture capacity of mixed broadleaf-conifer forest was maximal (5. 23 t/hm~2) , broad-leaf forest (4. 20 t/hm~2) , and Phyllostachys pupescens forest took second place (4. 14 t/hm~2) , and maximum moisture capacity of shrub forest was minimal(2.34 t/hm~2) .2) Through regression analysis, it concluded that retention deep of litter hadcontrafunctional relation to retention velocity with time variation. Variation range of maximal retention rate of 4-type of forest in Jinyun Mountain is 206.05% - 289. 13%, quantity gradation is: mixed broadleaf-conifer forest > shrub forest > broad leaved evergreen forest > Phyllostachys pupescens forest. The variation range of maximum water-holding capacity of litter is 33.40 - 80.60 t/hm~2, quantity gradation is: shrub forest > mixed broadleaf-conifer forest > broad leaved evergreen forest > Phyllostachys pupescens forest. Retention ability of shrub forest litter was approximately 2. 41 times of retention ability of Phyllostachys pupescens forest litter, whereas retention ability of mixed broadleaf-conifer forest litter was approximately 1.41 times of retention ability of Phyllostachys pupescens forest litter and retention ability of broad-leaf forest litter was approximately 1.29 times of retention ability of Phyllostachys pupescens forest litter.3) Quantity gradation of soil moisture storage of 4-tipe of forest in Jinyun Mountain was: shrub forest > mixed broadleaf-conifer forest > broad-leaf forest > Phyllostachys pupescens forest, but quantity gradation of soil moisture storage in 1.0 m deep under surface was: mixed broadleaf-conifer forest > shrub forest > broad-leaf forest > Phyllostachys pupescens forest. It indicated that soil of mixed broadleaf-conifer forest had better Water Resources conservation efficiency under condition of homology thickness of soiland its 1-meter-deep edaphic water-storage capacity was 5201. 50 t/hm~2, which was 1. 22 times of that of Phyllostachys pupescens forest.4) Through comprehensive analysis of water-holding capacity of storey, litter layer and soil horizon it concluded that quantity gradation of 4-type forest in Jinyun Mountain was: shrub forest > mixed broadleaf-conifer forest > broad-leaf forest > Phyllostachys pupescens forest, and soil horizon had maximal contribution to each type of forestat storey which water-storage capacity occupied more than 98% of total storage.5) Through grey correlation method analyzing effect of 4-type of forest on surface runoff and subterranean flow in Jinyun Mountain, conclusion was below: â‘ There was high degree of association between each vegetation status parameter and surface runoff coefficient and in all parameters litter thickness had the highest degree of association while cover degree of herbaceous layer and bush layer had lower degree of association and canopy density had lowest degree of association with surface runoff; In soil regime parameter soil infiltration velocity had the highest degree of association with subterranean flow while soil noncapillary porosity and soil thickness had higher degree of association and retention ability of soil saturation had lowest degree of association with subterranean flow. â‘¡Through analysing effect of different types of forest on runoff it concluded that shrub forest had the biggest impact on surface runoff; broad-leaf forest and Phyllostachys pupescens had bigger impact on surface runoff and mixedbroadleaf-conifer forest had minimal impact on surface runoff; But to effect on subterranean flow mixed broadleaf-conifer forest was biggest; Phyllostachys pupescens forest and broad-leaf forest was bigger; shrub forest was minimal. â‘¢Through analysing effect of different types of forest on runoff amount in Jinyun Mountain it showed that quantity gradation of producing runoff amount was below:broad-leaf forest > mixed broadleaf-conifer forest > Phyllostachys pupescens forest > farming terra > shrub forest;quantity gradation of producing surface runoff amount: Phyllostachys pupescens forest > mixed broadleaf-conifer forest > farming terra > shrub forest > broad-leaf forest;quantity gradation of producing subterranean flow amount: broad-leaf forest > mixed broadleaf-conifer forest > Phyllostachys pupescens forest > shrub forest > farming terra. According to regression analysis by the medium of SPSS13. 0 software, cube curve had been chosen as model of subterranean flow and rainfall amount of 4 types of forest in Jinyun Mountain because it had a best fitting outcome between rainfall amount and surface runoff and subterranean flow.6) With Analytical Hierarchy Process and fuzzing mathematics evaluating indicator system of forestry water resources conservation and recharge in Jinyun Mountain had been established and quantity gradation of integration score of 4 types of forest in Jinyun Mountain had been reached: shrub forest > mixed broadleaf-conifer forest > broad-leaf forest > Phyllostachys pupescens forest. It indicated that shrub forest had the best effect on water resources conservation and recharge and mixed broadleaf-conifer forest and broad-leaf forest had better effect and Phyllostachys pupescens forest had the worst effect. The outcome had an accord with research result of observation data which showed that established evaluating indicator system of forestry water resources conservation and recharge was creditable.7) Through the medium of shadow pricing, break-even cost method and analogism, quantity of ecologicalally functional value was about 25 700 yuan / hm~2, and among them value of water resources conservation and recharge of forest was 2 547. 28 yuan / hm~2 value of erosion protection was 863.75 yuan / hm~2, value of increasing soil fertility was5 600. 00 yuan / hm~2, value of increasing grain was 415. 00 yuan / hm~2, value of cleaner air was 16 226. 29 yuan / hm~2.