Today we take a look at the science of forest restoration and how effective it is at delivering benefits for our planet and people.

Largely in response to the global climate crisis, tree-planting campaigns are especially in vogue right now. Initiatives have been launched in recent years to plant trees for the future, to plant a billion trees, 8 billion trees, even a trillion trees.

Trees provide an abundance of benefits that can help solve a number of the environmental crises we’re facing. Planting new trees doesn’t just sequester carbon and help mitigate global warming, it can also provide badly needed habitat for wildlife and help address biodiversity loss. Trees can provide food and new sources of income for local communities while helping reduce soil erosion and preventing flooding. They keep communities cooler as global temperatures soar, and confer real psychological benefits for people.

But, contrary to popular opinion, planting a tree is not always an unmitigated boon to planet Earth. Planting the wrong trees in the wrong place can actually lead to the destruction of native biodiversity and deplete water tables, causing water scarcity. Some trees planted for beneficial purposes have become invasive, forcing local governments to spend large amounts of money and resources to remove them.

Of course, forest restoration does not always involve tree-planting — forests can and quite frequently do regenerate on their own. So when is tree-planting actually necessary, and when is it best to let forests restore themselves? What role do local communities need to play in reforestation initiatives? And how do we create programs that unlock the potential of reforestation efforts while avoiding the pitfalls?

To help us answer these questions, we speak with two experts in ecological restoration. First we speak with Robin Chazdon, a professor emeritus at the University of Connecticut, a research professor with Australia’s University of the Sunshine Coast, and a forest restoration consultant. Chazdon tells us about the decision-making process that goes into designing a reforestation project, whether or not today’s tree-planting campaigns are likely to be beneficial in the long run, and gives us some examples of both successful and failed forest restoration initiatives.

We also speak with Karen Holl, a professor of environmental studies at the University of California, Santa Cruz, who has studied tropical forest restoration for nearly three decades. Holl tells us about the conditions that are conducive to natural regeneration of forests and when tree-planting is necessary, what we know about the differences between planted and naturally regenerated forests, and why it’s so important for local communities to be involved in reforestation initiatives.

Further reading:

• ”Is planting trees as good for the Earth as everyone says?” (13 May 2021)

• ”Beyond tree planting: When to let forests restore themselves” (18 October 2021)

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Follow Mike Gaworecki on Twitter: @mikeg2001

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