Reforestation or natural regeneration: Which carbon sequestration strategy is most effective?

Tree planting is often seen as a ‘quick fix’ to sequestering carbon and supporting action towards ‘Net Zero’ targets. Much debate still surrounds how effective tree planting really is as a strategy, and how best to go about it.

Reforestation and regeneration
Reforestation and forest regeneration are key strategies for carbon sequestration.

In the fight against climate change, tree planting has become a key strategy to sequester carbon from the atmosphere. Carbon Dioxide (CO2) is a greenhouse gas, one of many contributing global warming, and inducing climate change. Trees, and all other plants, naturally sequester carbon from the atmosphere as part of photosynthesis.

Many governmental and corporate strategies rely on tree planting to sequester carbon, and 'offset' their emissions. Tree planting has been the subject of much debate, and a recent study analyses the different results of reforestation and regeneration strategies.

Reforestation vs Regeneration

Tree planting is a popular strategy to sequester carbon due to the amount of carbon trees can sequester during their lifetime. It is also relatively cheap and easy to implement in contrast to some other more complex strategies. Reforestation takes a proactive approach to planting trees in designated areas, often where there are currently no other trees. Regeneration, on the other hand, is a more ‘natural’ process whereby a forest is allowed to naturally regrow after disturbance.

A recent study analysed the difference in cost and efficiency between reforestation and regeneration in low- and middle-income countries. Researcher Jacob Bukoski says “Generally speaking, we can let forests regenerate on their own, which is slow but cheap, or take a more active approach and plant them, which speeds up growth but is more expensive.”

The study showed that neither strategy is outright better than the other, and that a mixed approach offers the most benefits. Bukoski continues “If your objective is to sequester carbon as quickly and as cheaply as possible, the best option is a mix of both naturally regenerating forests and planting forests. Which method is more cost effective in a given location is a function of multiple factors, including opportunity cost, relative carbon accumulation and harvest rates, and relative implementation costs.”

Reforestation
Reforestation is quicker than natural regeneration, but also more expensive.

Understanding which factors are at play in a given environment can help decision makers understand what strategies can derive the most benefit, and support efforts towards achieving environmental targets. Co-author Jeff Vincent adds “We hope our map will help governments, companies and other organisations use their forest restoration budgets more efficiently.”

Other methods of carbon sequestration

Tree planting and forest regeneration are just some of the ways in which carbon is being sequestered to 'offset' our emissions and mitigate global warming and climate change. Whilst this method can be very successful in some areas, it is not suitable in all environments. Other strategies used to sequester carbon include peat bog restoration, kelp forest growth, and urban vertical and roof vegetation planting.

A diverse range of strategies is vital to support carbon sequestration in different environments. Perhaps more important than sequestration is the continued effort to drive down emissions, and support strategies to achieve 'net zero' targets. Each of these strategies, including reforestation and regeneration, also supports biodiversity.

Whilst the biodiversity crisis and climate change are not the same thing, they are interrelated. Mitigating biodiversity loss, and even improving biodiversity supports ecosystem health, boosting ecosystem services including carbon sequestration which contributes to mitigating climate change. In turn, mitigating climate change supports environments and ecosystems, and maintains conditions vital for supporting biodiversity.

Reference of the news:

Busch, J., Bukoski, J.J., Cook-Patton, S.C. et al. Cost-effectiveness of natural forest regeneration and plantations for climate mitigation. Nat. Clim. Chang. (2024).