Analysis And Evaluation On Ecological Environmental Effects Of Main Models Of Forest Ecological Net System In Jiaonan City

Ecological environmental effects of main models of forest ecological net system in Jiaonan city were analyzed and evaluated by the way of the belts of shrub and herbage-backbone forest-water and soil conservation forest –fruit forest-farm protective forest network from coast to inner land. By the GIS technique, structure of forest ecological network regime and spatial stratification of main models was studied according to literatures and field surveys on the spots. Biodiversity of main models was researched using typical sampling method. The effects of improving soil properties, water conservancy and ameliorating microclimate were researched and analyzed by the routine methods. Compared with meadow belt, their comprehensive ecological environmental effects were evaluated by the AHP(Analysis of Hierarchical Process) method. The main results are as follows: Spatial stratifications of main models in 5 gradient belts are rather simple. That of Amorpha fruticosa L.+ herbage is better than Tamarix chinensis Lour.+herbage in the shrub and herbage belt. Robinia pseudoacacia L. forest is the best in the backbone forest belt. In the water and soil conservation forest belt, the horizontal structure of Pinus thunbergii forest is better than that of mixed forest of Pinus thunbergii and Quercus acutissima, however, their vertical structure is similar. The biodiversity indexes of main models are rather low, in which the Simpson indexes and Shannon-wiener indexes are 0.13～1.64 and 0.15～3.39 respectively. The biodiversities are getting better along the forest gradient belt from coast to inner land. For the biodiversity indexes, the model of Tamarix chinensis+herbage is better than Amorpha fruticosa+ herbage in the shrub and herbage belt, mixed forest of Pinus thunbergii+Robinia pseudoacacia+P. taeda+Fraxinus chinensis is better than P. thunbergii forest and Robinia pseudoacacia forest in the backbone forest belt, and P. thunbergii forest is better than mixed forest of P. thunbergii+Q. acutissima in the water and soil conservation forest belt. Main models improved soil properties and nutrient status. Furthermore, with the grads changing from coast to inner land, soil properties and nutrient content become better gradually. As far as the effect of soil improvement is concerned, A. fruticosa.+ herbage model is better than T. chinensis.+herbage model in the shrub and herbage belt, the capillary porocity of the former is bigger than that of the latter by 39.22%. R. pseudoacacia forest, of which the ratio of the capillary porocity occupying the total porocity reaches 81.49%, and lists the first in the backbone forest belt, mixed forest of P. thunbergii +R. pseudoacacia+P. taeda+F. chinensis is the second and P. thunbergii forest is the worst. Mixed forest of P. thunbergii.+Q. acutissima is better than P thunbergii forest in the water and soil conservation forest belt, the non-capillary porocity of the former is lower than that of the latter by 39.10%. The main models enhanced water conservation capability of litter and soil with the gradients from coast to inner land. In the shrub herbage grads, the water conservation capability of A. fruticosa+ herbage model (1881.60t/hm2)is greater than T. chinensis+herbage model(1573.30 t/hm2). In the backbone forest grads, the water conservation capability of litter shows R. pseudoacacia forest >mixed forest of P. thunbergii+R. pseudoacacia+P. taeda+F. chinensis > P. thunbergii forest, however, the total water conservation capacity shows P. thunbergii forest(1925.44 t/hm2) > mixed forest of P. thunbergi+R. pseudoacacia+P. taeda+F. chinensis(1608.21t/hm2) >R. pseudoacacia forest(1444.16t/hm2). The water conservation capability of mixed forest of P. thunbergii+Q. acutissima(2051.78 t/hm2) is better than P.