The effects of leaf phenology, construction cost and payback time on carbon accumulation in invasive plants Investigation of bud burst, shoot growth and leaf expansion in Populus euphratica of different ages LEAF PHENOLOGY OF WOODY SPECIES IN DECIDUOUS BROAD_LEAVED OAK FORESTS IN NANJING AREA, EAST CHINA LEAF EXPANSION OF THE DOMINANT WOODY SPECIES OF THREE DECIDUOUS OAK FORESTS IN NANJING, EAST CHINA