The effects of leaf phenology, construction cost and payback time on carbon accumulation in invasive plants Drought stress reduces the carbon accumulation of the Leymus chinensis steppe in Inner Mongolia, China Response of vegetation and soil carbon accumulation rate for China’s mature forest on climate change Carbon storage capacity of a Betula alnoides stand and a mixed Betula alnoides × Castanopsis hystrix stand in Southern Subtropical China: a comparison study