Study On Vegetation Restoration, Soil Nutrients And Their Relation Of Degraded Forest In Maoxian

The research was completed in two years (2003.7-2005.6) and granted by the State Key Basic Research Project (2002CB111505), Chinese National Natural Science Fund (30300047), Restoration Ecology Open Fund of Chengdu Institute of Biology, Chinese Academy of Science (R02-03) and University Ecology key Disciplines of Chongqing. According to the time series of ecological restoration, the abandoned land for 2 years, 3 years, and 5 years, forest of artificial restoration for 9 years and 16 years, and forest of natural restoration for 16 years were selected in our study in Dagou valley in Maoxian. The dynamic changes of soil nutrient, community microclimate and main population distribution pattern were studied and some suggestions are supplied to the restoration of the degradativevegetation.Species selection for the vegetation restoration attracts many scientists' attention. In our study, the dynamic spatial pattern of the dominant population in a community had been investigated. There were three dominant species, that is Quercus liaotungensis , Corylus yunnanensis and Camphlotropis macrocarpa in the communities with artificial restoration for 9 years,16 years, and natural restoration for 16 years. These three species in these communities showed intense aggregation distribution whose intensity and area increased with the restoration time. Further studies indicated: the aggregation intensity, pattern scale and number of patches of the seedling and sapling of Quercus liaotungensis showed ascending trend by time series. Effective restoration measures can promote the maturity of community and increase the competition capacity of the dominant species. The pattern performance and the dynamic change illuminated sufficiently that the local species with a strong competition capacity favor the restoration of degradative vegetation.Different plant communities form different microclimates, which affects the growth and development of the plants differently. In the study, the community microclimate followed these rules: (1) the light intensity, the ground surface temperature, the air temperature and their fluctuation decreased with the vegetation restoration time. Compared to the artificial restoration the natural restoration had higher air temperature but lower relative atmosphere humidity.(2)As the time series of restoration the water content of each soil layer in degradation vegetation became higher to some extent. The water content of the upper soil layer (0-15cm) and the middle soil layer (15-30cm) in artificial restoration community decreased, but in the underlayer increased with the forest age. And the water content in natural restoration community is higher than other communities of different types. As the time series, the gradual stability of community microclimate is a sign for the gradual maturity of community restoration. From the analyzing angle of community microclimate, the natural restoration measures are of benefit to the restoration and reconstruction of the degradative forest vegetation.Comparing the soil nutrient which is an important assessing index for the vegetation restoration in different time series can reflect the restoration more efficiently so that the effective restoration measures fit for different areas can be studied and found. Through the...