Restoring forests is critical for stopping climate change — but it costs money, and there’s more than one way to do it.
So which way is better for the climate, and more cost-effective, in a given place? That’s what a new study examines — and it could have huge implications for countries trying to reach their climate goals.
Published today in Nature Climate Change, the research compares two common methods of reforestation.
The first is tree plantations, which is what it sounds like: Plant trees and harvest them later, locking away some of the harvested trees’ carbon in construction materials. The second is “natural regeneration” — a fancy way to say “leave the forest alone and let it regrow naturally.”
Plantation forestry’s cash flow is easy to grasp: You sell the timber, you make money, you plant more trees. Revenue streams for natural regeneration, on the other hand, rely mostly on the sale of carbon credits to offset greenhouse gas emissions elsewhere — though unlike timber, the price of carbon is less well-established.
So which one offers a better climate “bang for the buck”?
The answer depends on where, said Jonah Busch, formerly a Friedman Science Fellow at Conservation International and the lead author of the paper.
“What we found is that there’s not a clear winner between these two,” Busch said. “There’s a time and a place for both types of reforestation, and if you were to only reforest the world with plantations, or if you were to only reforest the world with natural regeneration, you would be losing out on the climate benefit.”
A question of balance
Busch and fellow researchers mapped out nearly 140 low- and middle-income countries where it’s possible to do reforestation on a significant scale. They assembled new data on what common plantation-tree species are best suited for planting in different places, as well as the “opportunity costs” of growing crops or raising cattle instead of planting trees. At the same time, researchers looked at costs and benefits deriving from natural regeneration, balancing the costs of implementation against various scenarios of carbon revenue that such forests could generate.
The country-by-country maps that researchers produced — the first of their kind — can help governments to estimate where each method of reforestation may be more cost-effective at slowing climate change. Each method, they found, is more cost-effective in about half the places. The data, Busch hopes, will help policymakers make informed decisions on balancing costs, revenues, climate commitments and more.
“This research can help them determine the best mix of plantations and natural regeneration to meet reforestation targets. What this research is saying is that the mix should probably be more natural regeneration than it currently is.”
The research also found that reforestation is less expensive to implement than previously thought. That’s good news for efforts to fight climate change.
“Our research shows that the cost of reforestation based on hundreds of actual projects is far less than previously estimated, and thus should be a bigger part of the mix of efforts to stem climate change, including national climate pledges,” Busch said.
Busch cautions that when it comes to deciding what type of reforestation to do where, climate and cost are only two pieces of a bigger puzzle. People are right to consider the other considerable side benefits that forests generate, including livelihoods, habitat for wildlife; provision and filtration of fresh water; sources of food and income for local communities, and more.
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Bruno Vander Velde is the managing director of content at Conservation International. Want to read more stories like this? Sign up for email updates. Also, please consider supporting our critical work.
