Evaluation of remote sensing extraction methods for vegetation phenology based on flux tower net ecosystem carbon exchange data. Carbon exchange of Chinese boreal forest during its growth season and related regulation mechanisms. Variation characteristics of carbon storage flux over a mixed plantation of the Xiaolangdi area Relationship between net ecosystem carbon exchange and meteorological factors in a plantation in the hilly area of the North China Effects of nitrogen addition on carbon exchange in a typical steppe in Inner Mongolia Characteristics of Net Carbon Exchange over a Mixed Plantation ina Hilly Area of the North China