1. College of Forestry Northeast Forestry Univ. Harbin 150040 PR China
2. Dep. of Environmental Sciences Univ. of Basel Basel 4056 Switzerland
3. Georges Lemaître Centre for Earth and Climate Research Earth and Life Institute UCLouvain Louvain‐la‐Neuve 1348 Belgium
4. Dep. of Environment‐Soil Physics Units Ghent Univ. Ghent B‐9000 Belgium
5. State Key Laboratory of Vegetation and Environmental Change Institute of Botany, Chinese Academy of Sciences Beijing 100093 China
6. Dep. of Agronomy Iowa State Univ. Ames IA 50011 USA