Everybody likes trees. There is no anti-tree lobby. A global push to go beyond conservation of existing forests and start creating new ones goes back to 2011, when many of the world’s governments, including the United States, signed up to the Bonn Challenge, which set a goal of restoring some 860 million acres of forest globally by 2030. That is an area bigger than India, and enough to soak up 1.7 billion tons of carbon dioxide annually, adding almost a quarter to the current estimated forest carbon sink.
But the very unanimity of support for tree planting may reduce the impetus for detailed audits or critical analysis of what is actually achieved at each project. The paucity of follow-up thus far has resulted in a great deal of wasted effort – and money.
In an investigation published last year into extensive government-organized tree planting over several decades in the northern Indian state of Himachal Pradesh, Eric Coleman of Florida State University and colleagues found little evidence that it had resulted in more tree cover, carbon uptake, or community benefits.
Tree planting in the Philippines under its National Greening Program has also been a widespread failure, according to a 2019 study by the government’s own Commission on Audit. Ministers imposed unachievable planting targets, it said, resulting in planting “without … survey, mapping and planning.” The actual increase in forest cover achieved was little more than a tenth of that planned.
The causes of failure vary but include:
- planting single species of trees that become vulnerable to disease;
- competing demands for the land;
- changing climate; planting in areas not previously forested;
- and a lack of aftercare such as watering saplings.
Every year, “millions of dollars” are spent on reforesting landscapes, according to Lalisa Duguma of World Agroforestry, an international research agency in Nairobi, Kenya. Yet “there are few success stories.” Typically only a minority of seedlings survive, he says, because the wrong trees are planted in the wrong places, and many are left untended, in part because ownership and management of trees is not handed over to local communities.
Such failures often go unnoticed, believes Duguma, because performance indicators measure planting rates not survival rates, and long-term oversight is minimal because projects typically last three years or less. The result is “phantom forests.”
Phantom forests are increasingly sabotaging efforts to rein in climate change. This happens when planters claim the presumed take-up of carbon by growing forests as carbon credits. If certified by reputable bodies, these credits can count toward governments meeting their national emissions targets or be sold to industrial polluters to offset their emissions.
But even the best-planned and best-audited planting projects can come undone, leaving behind non-existent forests and uncaptured carbon.
The California Air Resources Board (CARB) is a major certifier of carbon-offset forests across the American West. It approves the carbon credits generated by the forests, which are then sold to industrial polluters in California who want to offset their emissions in line with state regulations.
But climate change is leaving the western U.S. increasingly vulnerable to wildfires. To meet this challenge, CARB requires offset developers to hold back from sale a proportion of the credits, which they put into a central buffer fund as insurance against a variety of potential mishaps during the 100-year planned lifetime of the offsets. Up to 4% of credits insure against wildfires. That buffer fund picked up the tab, for instance, when 99% of the carbon in a forest offset project on Eddie Ranch in Northern California burned in a fire in 2018.
But the CARB certification system is running out of buffer carbon, according to an analysis published in August by ecologist Grayson Badgley at CarbonPlan, a nonprofit climate solutions database. He found that just 7 years into its supposed century-long insurance, 95% of the wildfire buffer has been consumed by just six fires across the West. Danny Cullenward, an environmental lawyer at American University in Washington, D.C. and co-author of the CarbonPlan analysis, calls this “a giant Ponzi scheme.”
Many forest ecologists say creating space to allow nature to do its thing is usually a better approach to restoring forests than planting. “Allowing nature to choose which species predominate … allows for local adaptation and higher functional diversity,” argues one advocate, Robin Chazdon of the University of Connecticut, in her book Second Growth. For mangroves, Wetlands International now recommends abandoning widespread planting and instead creating areas of slack water along coastlines, where mangroves can naturally reseed and grow.