Contribution of ecosystem services and dis-services from trees to agricultural systems. The contribution of forests, trees and agroforestry to food production systems. Trees and forests regulate functions that produce services and goods directly to produce food or can be transformed indirectly to support crop and livestock production. Forests and trees also compete with agriculture for productions resources. Additionally, trees ecosystems may serve as habitat for pests and diseases in in what is often referred to as ecosystem dis-services. Adapted from Zhang et al. 2007.