Journal Article Research Support, Non-U.S. Gov't 142M471B3J 7YNJ3PO35Z CO2 fertilization effect Carbon Dioxide Carbon Isotopes China Heterocyclic Compounds Hydrogen Ketones N762921K75 Nitrogen Research Support, U.S. Gov't, Non-P.H.S. afforestation attribution climate change climatic warming deciduous trees detection greening trend interspecific differences in spring phenology leaf-out date nitrogen deposition phenological shift phenology photoperiod temperature sensitivity temperature-relevant period