SEASONAL CHANGES OF PHOTOSYNTHETIC CHARACTERISTICS IN 12 TREE SPECIES INTRODUCED ONTO OIL SHALE WASTE Ecological restoration of oil shale waste dumps Study on Effects and Mechanisms of Applying an Activated Phosphatic Manure to Citrus grandis Osbeck Responses of Photosynthesis in Two Woody Plants to Oil Shale Residue Pollution Differences in Photosynthesis and Plant Growth of 26 Woody Species at the Oil Shale Waste Dump Stomatal Gas Exchange in Leaves of Major Trees on the Oil Shale Residue in Maoming, Guangdong The soil and vegetation of oil shale dump in Maoming city, Guangdong Province The Response of Young Slash Pine Plantation to Fertilization on the Shale Red Soil Ecological Effect of Phytoremediation on Oil Shale Waste Dumps