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These days everyone seems to thinks that "planting trees" is an important solution to the climate crisis. They're mostly wrong, and in this paper we explain why. Instead of planting trees, we need to talk about people managing landscapes. 1/x https://academic.oup.com/bioscience/advance-article-abstract/doi/10.1093/biosci/biaa094/5903754?redirectedFrom=fulltext
We highlight 10 pitfalls of tree planting, and discuss how a focus on people who manage landscapes will work. 2/x
The first pitfall is that it is ecosystems, not tree planting campaigns, that capture and store carbon. Tree planting campaigns have high failure rates, and many ecosystems with sparse tree cover store large amounts of carbon below the ground - e.g. see https://onlinelibrary.wiley.com/doi/full/10.1111/rec.12989 3
The second pitfall is that protecting ecosystems, not planting trees, is the most cost effective natural climate solution. Tree planting campaigns divert funding from this low cost priority, and fail because they do not address the drivers of forest loss. 4/x
The main driver of forest loss is export-oriented commodity agriculture. There are a number of ways of addressing this problem, which are outlined very well here. https://ipbes.net/assessment-reports/ldr 5/x
In order to protect carbon in ecosystems, we need to secure the property rights of people who have incentives to conserve that carbon - often indigenous or otherwise resource-dependent people in the global south. 6/x https://rightsandresources.org/publication/urgency-and-opportunity/
The third pitfall is that tree planting is often not necessary to restore ecosystems. In many situations, trees can grow naturally without anyone needing them to be planted, and planting the wrong trees in the wrong places can hinder regrowth 7/x http://apps.worldagroforestry.org/downloads/Publications/PDFS/WP20001.pdf
When restoration does involve planting trees, it often works better to plant a small number of trees that target specific goals - such as establishing seed sources or making the new forest more economically valuable to local users, rather than a large-scale planting program. 8/x
The fourth pitfall is that tree plantations sequester less carbon, less securely, than naturally regenerated forests. Widely used plantation practices result in forests with little long-term carbon storage and emphasize species that increase fire risk 9/x https://www.nature.com/articles/d41586-019-01026-8?fbclid=IwAR1y18awB9nQqoqyRyPrEQD-OzZRBvm0K8N8YrmPYX5qvOPq6UTTSAyu7yQ
The fifth pitfall is that Tree plantations in grasslands, shrublands, and peatlands destroy biodiversity. For example global restoration plans would destroy the iconic African savannas, replacing them with large scale plantations. 10/x https://www.sciencedirect.com/science/article/pii/S0169534719302526?casa_token=sYf1Ex4OTK4AAAAA:rgv_NhNYUL5jKQrWzuuTx2zPD5HvWJz8KWY0F1IqAW5-YXJdRkJR9riNkNDhR-HMBa2BmtfEpQ
The 6th pitfall is that trees can reduce water availability. Yes, trees improve ground and surface water recharge, but they also use alot of water, and the balance between these is complicated and can only be determined in a site specific fashion. 11/x https://science.sciencemag.org/content/310/5756/1944.abstract?casa_token=8VpwlO59BKcAAAAA:LuQkHREIG5xWe0XQGRmZlKBI603osP94qK2noJgGmuLk_fnoXCrv1tH3EIIpb-GB2aHEJYzfvoHVJg
The 7th pitfall is that trees in the wrong places actually warm the atmosphere more than their carbon storage contributes to cooling. This is because trees are dark - so they absorb more heat than surfaces like snow or dry grass. 12/x https://www.nature.com/articles/ncomms7603?origin=ppub
The 8th pitfall is that perverse financial incentives lead to rushed planting and high tree mortality. Hardly a week passes where I don't read a story about a tree planting drive which was rushed for publicity and no allocation was made for maintenance. The trees are dead. 13/x
The 9th pitfall is that tree planting can threaten rural livelihoods. 300 million people live on land targeted for restoration, and many of them depend on subsistence agriculture or grazing animals - land uses that often conflict with restoration. 14/x https://doi.org/10.1038/s41559-020-01282-2
The 10th pitfall is that tree planting targets the global south to capture emissions from the global north, raising fundamental questions of environmental justice. If tree planting is beneficial or benign, there may be no problem... 15/x
But we show that tree planting has the potential to disrupt the livelihoods of hundreds of millions of the world's poorest people while also destroying biodiversity and undermining the provision of ecosystem services like water. 16/x
Is it fair for wealthy consumers to ask very poor people to sacrifice their livelihoods so we can continue to consume? 17/x
We suggest that instead of focusing on tree planting as a "natural climate solution" we need to focus on "people-centered climate solutions." This means supporting social systems that support people to conserve ecosystems. 18/x
Long term investments in tree growing require secure land tenure for rural and indigenous people, alongside incentives and access to investment capital. These are lacking for many in the global south, and should be a priority for those who care about restoration. 19/x
This new brief from @RightsResources lays out some of what needs to be done: https://rightsandresources.org/publication/urgency-and-opportunity/
We have a discipline called "restoration ecology" but restoring ecosystems requires intervening in social systems to change their relationships with the land. To that end, I propose the development of a new field of "restoration science" which blends social and biophysical. /end
I'd like to acknowledge my coauthors who are on twitter @jennifer_pow @shishirbasant @ProfEricColeman @this_is_divya @PKashwan (apologies if I missed someone) and feel free to DM me for full text.
