What impact does reforestation have on carbon sequestration and biodiversity?

Reforestation can help draw carbon dioxide from the air while rebuilding habitat, but the results depend on what is planted, where, and how the forest is managed.

As trees grow, they store carbon in trunks, branches, roots, and leaves. Forest soils can store carbon too. This forest carbon storage builds over time, so a newly planted area will not absorb carbon at the rate of a mature forest straight away. The benefit also lasts only if the forest survives; logging, severe fires, drought, or land-use change can release stored carbon back into the atmosphere. Reforestation helps, but it cannot replace reducing fossil-fuel emissions.

For biodiversity, restoring a mix of locally native trees and other plants can provide food, shelter, and breeding sites for wildlife. Connecting restored areas to existing forests can improve wildlife habitat connectivity, making it easier for species to move and recover. By contrast, planting a single fast-growing tree species may store some carbon but offer limited habitat and can put pressure on local water supplies.

The strongest results usually come from restoring the ecosystem that belongs in that place, rather than simply maximizing the number of trees. That means considering native plant diversity, soil conditions, water availability, and long-term protection.