N Mineralization and Nitrification in a Primary Lithocarpus xylocarpus Forest and Degraded Vegetation in the Ailao Mountain, Yunnan Province Dry-Season Dynamics of Soil Inorganic Nitrogen Pools in Primary Lithocarpus xylocarpus Forest and Degraded Vegetation in Ailao Mountain, Yunnan Province A Preliminary Study of the Regulation and Competition of the Dominant Plant Populations in Xujiaba Region, Ailao Mts Tunnan STUDY ON THE ACCUMULATION AND BIOLOGICAL CYCLES OF CHEMICAL ELEMENTS IN LITHOCARPUS XYLOCARPUS FOREST IN NORTH SIDE OF AILAO MOUNTAIN Niche Breadths and Overlaps of Dominant Species of Lithocarpus xylocarpus Community in Ailao Mountains, Yunnan, China