Farmer Managed Natural Regeneration (FMNR) comprises a set of practices used by farmers to encourage the growth of native trees on agricultural land. FMNR is reported to deliver a number of positive impacts, including increasing agricultural productivity through soil fertility improvement and feed for livestock, incomes, and other environmental benefits. It is widely promoted in Africa as a cost-effective way of restoring degraded land, that overcomes the challenge of low survival rates associated with tree planting in arid and semi-arid areas. Despite being widely promoted, the evidence for these bold claims about FMNR has not been systematically analyzed. This paper reviews the scientific evidence related to the contexts in which FMNR is practiced across sub-Saharan Africa, how this influences the composition of regenerating vegetation, and the resulting environmental and socio-economic benefits derived from it.

This reveals that quantitative evidence on FMNR outcomes is sparse and mainly related to experience in the Maradi and Zinder regions of Niger. There is little mechanistic understanding relating how context conditions the diversity and abundance of regenerating trees and how this in turn is related to ecosystem function and livelihood benefits. This makes it difficult to determine where and for whom FMNR is an appropriate restoration technique and where it might be necessary to combine it with enrichment planting. Given the need for viable restoration practices for agricultural land across Africa, well beyond the climatic and edaphic contexts covered by existing FMNR studies, we recommend research combining functional ecology and socio-economic assessments, embedded as co-learning components within scaling up initiatives. This would fill key knowledge gaps, enabling the development of context-sensitive advice on where and how to promote FMNR, as well as the calculation of the return on investment of doing so.

It is estimated that up to 65% of productive land in Africa is degraded, exacerbating poverty, food and nutrition insecurity, loss of biodiversity, conflicts and insecurity (UNCCD, 2013; ELD-UNEP, 2015). Land restoration has the potential to increase food and nutritional security, sequester carbon, recharge groundwater and reverse biodiversity loss (UNCCD, 2013; Nkonya et al., 2016). The United Nations General Assembly declared 2021–2030 the decade of ecosystem restoration (UN, 2019). African governments, under the AFR100 initiative, voluntarily committed to restore at least 100 million ha by 2030 as their contribution to the Bonn challenge (which targets restoration of 100 M ha by 2020 and 350 M ha by 2030); the 2010 Aichi Convention on Biological Diversity (which targets restoration of at least 15% of degraded ecosystems globally) and the Paris accords (CBD, 2010; UNFCCC, 2015). Questions have been raised about how realistic these restoration targets are, considering that annual deforestation continues to exceed restoration in Africa.