摘要：The recent interest in multi-functional agricultural landscapes has not been matched withformal assessment of the roles that trees play across the spectrum of ecosystem services (ESs)provided in Sub-Saharan Africa (SSA). A structured literature review (1995–2014) assessed 350journal articles about provision of one or more ESs by trees on farms and in agriculturallandscapes in SSA. This revealed information on 15 ESs from studies in 23 countries coveringarid (1% of studies), semi-arid (49%), sub-humid (26%) and humid (24%) agro-ecologicalzones. The majority of the studies reported provisioning (39%) and supporting (35%) followedby regulating (26%) ESs while studies on cultural services were scarce. Beneficial impacts oftrees were dominating (58%), in particular in semi-arid zones where they were associatedwith enhancing water and nutrient cycling. A decline in some ESs was reported in 15% of thestudies, while 28% found no effect of trees. Although the effects of trees were mainly positive,a decline in crop production was noted as a key trade-off against the provisions of ESs, suchas modification of microclimate. This highlights the need to manage trade-offs amongimpacts of trees on ES provision to reduce competition and increase complementaritybetween trees and crops.
