Managing afforestation and reforestation for carbon sequestration: considerations for land managers and policy makers

Background

This chapter focuses on managing afforestation & reforestation projects with an eye towards carbon sequestration. While temperate regions contain the majority of the world’s naturally regenerated and planted forests, the most rapid rates of reforestation occur in the tropics.

Goals & Methods

Site selection is one of two key success factors for reforestation projects. Building soil carbon should be treated as one among several major criteria, including water quantity, water quality, biodiversity, and human needs. If a potential site would bring unacceptable changes to any of the above categories, it may not be a preferred site for afforestation. Species selection is the other key success factor. Mixed-species forests have the potential to sequester and store more carbon than monocultural forests. Management practices can improve forest carbon sequestration, but have additional consequences. Site preparation and fertilization may improve tree growth, but produce their own carbon emissions. Thinning has a negative short-term impact on forest carbon stocks but can improve tree vigor and reduce fire and disease risks in the long run.

Conclusions & takeaways

Afforestation of sites that have historically not supported forests often has adverse effects on other values such as water availability and human uses. Policymakers should consider whether their incentives for afforestation promote this type of activity. Using nitrogen-fixing species in place of fertilizers can result in reduced emissions while improving forest biomass. Policymakers should also seek to promote mixed-species plantations of various sizes as alternatives to the more common large monocultural plantations.