Study On Forests Complex And Microclimate Characteristics In Central Districts Of Chongqing

Urban forest is the most natural part of urban ecological system, and it can bring into various ecological functions, maintain the balance of urban ecosystem and ensure the healthy development of cities to a certain extent.There have been a lot of researches on the urban forest. The main researches are structure research about different area and greenland.And it also researches the structure type, such as the research about arbor,shrubs and grass.But there is a little research about the complex of different communities, not only about landscape but also about plant communities.Also there is less research about the change which the diffreret complex communities changes with the elevation changes.This thesis selects the overpass (Nanbin Road to Nanshan Park) at the west slop of Causeway mountain as study object.It bases on the data from survey of 576 plots and principles of ecology.lt analyses the relationship between crown density, species diversity and the altitude.lt compares the difference about community ecology benefit when different community types, different habitat types, different crown density.At last, it carries out the evaluation on urban forest comfort through the temperature, humidity and the speed of wind. The result shows:1. This research is mainly aimed at arbor and shrubs.The kinds of plant is 94 in total at research areas which attach to 47 fatalism and 81 genus.Among them, there are 8 types gymnosperm of 4 fatalism and 86 types angiosperm of 43 fatalism.We find that there are 53 types of arbors and 41 types of shrubs, including 3 types of climbing shrubs; 48 types of evergreen trees,46 types of deciduous trees; 6 types of coniferoustree,88 types of hardwood. With altitude rising and slope increasing, the crown density is more and more bigger, also the species diversity is a tendency to increase.2. The best cooling effect of different types forests is natural forests, second is the semi-natural forest, plantation is in the final place.3. At the same time and the same height, the overall temperature trend is mixed broadleaf-conifer forest< coniferoustree< evergreen broad-leaved forest; the general trend of air relative humidity is mixed broadleaf-conifer forest> coniferoustree> evergreen broad-leaved forest. The mixed broadleaf-conifer forest is similarly to the evergreen broad-leaved about light intensity, when at the same height.4. There is 10.4 degrees gap about maximum temperature between the crown density which is less than 0.2 and more than 0.6 in the forest, the latter is higher fifty-one percent than the former.The order about the ability reducing light intensity when different crown density is that:plant communities of the crown density which is more than 0.6> plant communities of the crown density which is between 0.4 and 0.6> plant communities of the crown density which is between 0.2 and 0.4> plant communities of the crown density which is less than 0.2.5. This thesis surveies the air negative oxygen ions about different type of community.The content of air negative oxygen ions show this sequence that the coniferous forest> mixed forest>broad-leaved forest.6. When comparing the comfort of different forest types, we find that the natural forest is the most comfortable, second is the semi-natural forest, plantation is in the final place.