The ‘parklands’ that form the most widespread farming systems in the Sahelian zone of West Africa are farming systems in which annual crops are grown under scattered trees preserved from the natural vegetation by farmers clearing the woodlands to make crop fields. Being mixed agricultural systems, the interactions between trees and crops have always been a key element determining the management options applied by farmers. A combination of field trials, observational studies and modeling has been deployed to understand soil–tree–crop interactions, including sharing of growth resources by the system components. Despite scientific advances, there are still some methodological challenges in determining the tradeoffs and synergies between and among goods and services, and how to boost the provisioning, supporting and regulating functions of such agroforestry systems. Providing such ecosystem service functions is critical in the quest for ensuring food security while achieving adaptation and mitigation goals in vulnerable environments like the drylands.