title: Global patterns of the dynamics of soil carbon and nitrogen stocks following afforestation: a meta-analysis.
abstract: • Afforestation has been proposed as an effective method of carbon (C) sequestration; however, the magnitude and direction of soil carbon accumulation following afforestation and its regulation by soil nitrogen (N) dynamics are still not well understood. • We synthesized the results from 292 sites and carried out a meta-analysis to evaluate the dynamics of soil C and N stocks following afforestation. • Changes in soil C and N stocks were significantly correlated and had a similar temporal pattern. Significant C and N stock increases were found 30 and 50 yr after afforestation, respectively. Before these time points, C and N stocks were either depleted or unchanged. Carbon stock increased following afforestation on cropland and pasture, and in tropical, subtropical and boreal zones. The soil N stock increased in the subtropical zone. The soil C stock increased after afforestation with hardwoods such as Eucalyptus, but did not change after afforestation with softwoods such as pine. Soil N stocks increased and decreased, respectively, after afforestation with hardwoods (excluding Eucalyptus) and pine. • These results indicate that soil C and N stocks both increase with time after afforestation, and that C sequestration through afforestation depends on prior land use, climate and the tree species planted.
authors.affiliation: Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA. dejun.li@ou.edu
authors.forename: Dejun
authors.initials: D
authors.lastname: Li
authors.forename: Shuli
authors.initials: S
authors.lastname: Niu
authors.forename: Yiqi
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000383:Agriculture; D002244:Carbon / Q000032:analysis*; D057965:Carbon Sequestration; D002980:Climate; D009584:Nitrogen / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D014197:Trees; D014329:Tropical Climate
chemical_list: D012987:Soil; D002244:Carbon; D009584:Nitrogen