By Chris Lang
“Scientists, corporations, mystics, and movie stars have convinced policymakers around the world that a massive campaign to plant trees should be an essential element of global climate policy. Public dialogue has emphasized potential benefits of tree planting while downplaying pitfalls and limitations that are well established by social and ecological research.”
That’s the opening sentence in a recent paper published in BioScience. The lead author is Forrest Fleischman of the Department of Forest Resources, University of Minnesota. “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,” Fleischman writes on Twitter. “Instead of planting trees, we need to talk about people managing landscapes.”
The paper is titled, “Pitfalls of Tree Planting Show Why We Need People-Centered Natural Climate Solutions” and lists “ten pitfalls and misperceptions that arise when large-scale tree planting campaigns fail to acknowledge the social and ecological complexities of the landscapes they aim to transform”.
Unfortunately, the authors of the paper do not mention that natural climate solutions are just another way of avoiding the urgent need to keep fossil fuels in the ground. The authors make no mention of the fact that oil corporations, including BP, Shell, Total, Equinore, and Eni, are planning to pour hundreds of millions of dollars into natural climate solutions, while continuing to extract more oil.
Of course, socially just, people-centred ecosystem restoration is a worthwhile goal. But to address the climate crisis we need to leave fossil fuels in the ground. We cannot trade the carbon stored in ecosystems against continued extraction and burning of fossil fuels. Yet that’s precisely what the oil industry, and the big NGOs that are promoting natural climate solutions, want to do.
The authors do raise the issue of social justice and point out that while the majority of carbon emissions come from the global north, tree planting campaigns focus on the global south. And the paper’s critique of the problems associated with the current tree planting craze is generally excellent. Here are the authors’ ten pitfalls of tree planting – each one starts with a quotation from the authors:
1. Ecosystems, not tree planting campaigns, capture and store carbon
“Despite the importance of below-ground biomass and soil organic matter to carbon storage, the most visible and easily measured carbon resides above ground in trees.”
The high visibility and the fact that everyone likes trees means that proponents of natural climate solutions promote tree planting above all else. But massive tree planting programmes have high failure rates. Planting trees in savannas and peatlands destroys biodiversity and can end up emitting more carbon than it stores.
2. Preventing ecosystem destruction is the most cost-effective natural climate solution
“Because ecosystems are crucial to carbon sequestration, avoiding deforestation, improving forest management, and protecting grasslands, peatlands, and shrublands from conversion should be the priority.”
Addressing the drivers of deforestation is crucial, otherwise the destruction will just be shifted to somewhere else. The authors note that securing the rights of rural and Indigenous people is essential. They argue in favour of “just compensation for the carbon that ecosystems store”, but do not mention where this money should come from or to whom it should be paid.
3. Forests can regrow on deforested land without tree planting
“In most places where reforestation is desirable, forests can regenerate naturally from seeds or resprouts, even in landscapes that appear to be highly degraded.”
It is also cheaper than tree planting, and results in faster recovery of forests, more carbon storage, more biodiversity, and more benefits for local communities. Assisted natural regeneration can include planting trees that are beneficial to local communities.
4. Tree plantations sequester less carbon, less securely, than naturally regenerated forests
“Global forest restoration initiatives promote fast-growing plantations of commercial pulp and timber species as a natural climate solution despite clear evidence that these plantations lead to little long-term carbon storage.”
Even worse, pine and eucalyptus trees burn easily, which results in the carbon temporarily stored in the trees being released to the atmosphere.
5. Tree plantations in grasslands, shrublands, and peatlands destroy biodiversity
“Establishing tree plantations where forests did not historically occur destroys the habitats of plants and animals adapted to open ecosystems and threatens the livelihoods of people dependent on those ecosystems to produce wild game and domestic livestock.”
The authors give the example of savannas in Africa that are threatened by large-scale afforestation campaigns.
6. Trees can reduce water availability
“In the wrong places, planted forests [sic] deplete ground water and can cause streams to dry up.”
The use of the oxymoronic “planted forests” instead of “plantations” is surprising in a paper that is rightly critical of tree planting campaigns. As Ricardo Carrere pointed out in a 1999 World Rainforest Movement briefing, “This confusion between a crop (of trees) and a wood or forest is the starting point of all propaganda in favour of tree plantations.”
The authors cite research by Robert Jackson, professor of Earth System Science at Stanford University. In 2005, Jackson was lead author of a paper in Science. “Carbon sequestration strategies highlight tree plantations without considering their full environmental consequences,” Jackson and colleagues wrote. Which is something of an understatement given the recent craze for planting one trillion trees.
7. Trees can warm the atmosphere
“Trees, particularly evergreen conifers, are darker and taller than most other land covers, and therefore absorb more visible and ultraviolet sunlight (shortwave radiation) compared to highly reflective bare ground, snow, or grasses.”
Planting trees can decrease the albedo of the ecosystem and more sunlight is absorbed and emitted as heat.
8. Perverse financial incentives lead to rushed planting and high tree mortality
“When ambitious targets for the number of hectares or number of saplings planted are rewarded with large monetary commitments, governments and other organizations tend to focus on the act of planting rather than long-term maintenance to ensure tree survival and growth.”
The drive to meet tree planting targets can result in trees being planted incorrectly, in the wrong places, and without the support of local people.
9. Tree planting threatens rural livelihoods
“Tree planting programs often target ecosystems or farmland that rural people depend on for subsistence livelihoods. Frequently these people have insecure land tenure, and the land may be viewed by governments or other actors as ‘available’ for tree planting.”
Replacing farmland with trees has serious implications for the livelihoods of local communities, as in the case of Green Resources’ industrial tree plantations in Uganda. Agricultural workers can lose their jobs, and local food prices increase.
10. Tree planting targets the global south to capture emissions from the global north
“Proponents of large-scale tree planting, such as Plant-For-the-Planet and the Trillion Tree Campaign, equate tree planting with climate justice and prosperity for the global south. Unfortunately, these proponents ignore the opportunity costs of using land for trees instead of other economically beneficial activities.”
The authors add that proponents of tree planting for climate mitigation must answer critical questions of social justice. They ask, “Is it just for the states of the global north to ask the world’s poorest people and most threatened ecosystems to bear the costs of fossil fuel emissions?”
PHOTO Credit: Fleischman et al (2020) – “Government officials inspect a 2-year-old plantation of Eucalyptus clones on government-controlled land in Telangana, India. Low biodiversity, soil disturbance, exacerbated fire risk, altered hydrology, and restricted access to local people mean that this afforested [sic] land, although a potentially valuable source of wood fiber for paper, disrupts rural livelihoods and should not be considered a natural climate solution.”
It has been suggested that the answer to global climate change lies in so-called “green solutions” – major tree planting programs (the ”Trillion Trees Proposal” by Zurich-based Crowther Labs-ETH), and the World Bank’s REDD+ program (reduction of emissions from forest degradation and deforestation) where carbon emitters can off-set their emissions by purchasing carbon credits from forests protected through the REDD program. Both proposals have been enthusiastically supported by the fossil fuel and transportation industries because they rely entirely on highly-speculative “carbon-offsets” rather than measurable carbon emission reductions.
There are four fundamental scientific problems with the so-called “green solution” programs when it comes to climate change mitigation:
1. Leakage: While deforestation may be avoided or reduced in one area, forest exploitation and degradation may simply shift to a different locale.
2. Additionality: It is impossible to estimate what might have happened in a given area had such programs not been implemented.
3. Permanence: Carbon stored in trees is only temporary, i.e. all trees will eventually die, be attacked by insects, or in drier climates may be subjected to catastrophic wildfire, and release carbon back to the atmosphere.
4. Measurement: Accurately measuring the amount of carbon stored in forests and forest soils is extremely complicated, and prone to significant errors, especially in complex and species-rich tropical forests.
I have had serious concern over the lack of clear criteria in so-called “Green Solutions” in judging the acceptability and relevance of programs. Perhaps even more important are the difficulties of establishing clear standards for the methodology of determining reference emission levels and estimating/ projecting future emissions under different land/resource use alternatives – which to me is a key to developing appropriate natural carbon reduction and sequestration programs.
In short, many of these “green solutions” (particularly the “Trillion Tree Program”) are the result of “desk exercises” by “computer geeks” with little or no practical ecological or social expertise. Although properly conceived ecological restoration, if carefully implemented, can have a role in mitigating climate change, as well as fulfilling other important ecological services, it is no substitute for the fact that fossil fuel consumption will need to be significantly curtailed in order to meet the targets of the Paris Agreement and longer-term reductions in carbon emissions. Such action should be accompanied by policies that prioritize the conservation and ecological recovery of intact, bio-diverse ecosystems, irrespective of whether they contain trees.
So, to reiterate, selective “heroic” tree planting (not to be confused with ecologically-based forest ecosystem restoration/recovery programs) are unlikely to help, and it’s time to stop suggesting there is a “nature-based solution” to continued fossil fuel use at its current levels. Sorry folks – there just isn’t! We just have to reduce our own domestic use, and stop “pimping” fossil fuels to other parts of the world in return for cheap consumer goods, which are in turn “pimped” on the backs of local, seriously exploited workers. This commercial relationship is neither environmentally nor socially sustainable.