A few weeks ago, British Columbia rolled out its Climate Leadership plan, which was generally met with condemnations from climate and environmental activists (the plan fails to, among other things, raise the Canadian province’s tax on carbon). But one part of the plan seems to be generating some buzz: the Forest Carbon Initiative, a pledge to plant more than 740,000 acres of forest over the next five years.
The idea, according to the dean of the University of British Columbia’s forestry department, is to turn British Columbia’s forests from a carbon emissions source — a title they’ve earned in recent years due in large part to forest fires, decay, and slash burning—back into a carbon sink. Plant trees, the plan goes, and British Columbia will help slow the pace of climate change.
British Columbia is far from the first place to deploy this logic in an effort to combat climate change. Earlier this summer, volunteers in India smashed a world record by planting 49.3 million tree saplings on July 11. Last year, volunteers in Ecuador planted 647,250 trees from 200 species in one day. In 2014, Men of the Trees planted 100,450 trees in Perth, Australia in a single hour.
Reforestation — the concept of planting trees to try and recreate missing forests, or strengthen existing ones—was even included as a major part of last year’s Paris climate agreement, with a handful of key countries, including Brazil, Indonesia, Peru, and the United States, committing to “intensifying efforts to protect forests.”
But planting trees in an effort to slow climate change is a complicated solution to a complicated problem — and experts caution that countries looking to implement robust reforestation programs need to be extremely deliberate in the kind of reforestation and forest management that they choose.
“Trees, as they grow, take carbon out of the atmosphere. The more wood you have, the more carbon is on land and out of the atmosphere.”
“In general, [reforestation] is all good in the sense that trees, as they grow, take carbon out of the atmosphere,” Richard Houghton, a senior scientist with the Woods Hole Research Center, told ThinkProgress. “The more wood you have, the more carbon is on land and out of the atmosphere. That’s the reason why planting trees is good.”
There are, however, a few factors that generally make reforestation a better idea in some parts of the world than in others. In northern boreal forests, for example, planting more trees can actually have a warming effect, even if trees are taking up carbon dioxide as they grow. That’s because trees in boreal forests can obscure snow that falls during winter months, which normally helps to reflect sunlight — and therefore heat. When trees are planted, they absorb the sunlight instead of reflecting it (it’s the same albedo effect principle as melting sea ice in the Arctic — dark ocean absorbs sunlight instead of white ice reflecting sunlight).
The particular kind of forest being planted also contributes to the efficacy of reforestation programs. When forests are planted to mimic natural forests, they can offer more ecosystem benefits than forests simply planted for the sake of planting trees — whether as part of a one-off project or as part of a tree plantation.
“Natural forests do a lot of things good for us, other than carbon,” Houghton said, nodding to things like biodiversity. “Plantations are more specialized, for wood or for protection against wind erosion.”
One of the most famous examples of reforestation as a tool against wind erosion is China’s Great Green Wall — between 1978 and 2014, China planted 66 billion trees along the border between the country and the encroaching Gobi Desert, in an effort to keep wind erosion from pushing the boundary of the desert farther into China’s grasslands and native forests. Critics have questioned the project’s effectiveness, however, arguing that the survival rate for non-native trees planted in extremely dry conditions is low.
Houghton agrees that, when it comes to planting trees, location is key for both the survival of the trees and the efficacy of the project as a carbon sink — and many times, working to preserve an already existing forest can be more successful than trying to create a forest where there previously was none.
“It is easier to maintain existing forests in harsh environments than it is to replace a forest.”
“It is easier to maintain existing forests in harsh environments than it is to replace a forest,” he said.
Perhaps the most complicating factor in reforestation as a means to combat climate change, however, is climate change itself. Across large parts of western North America, forests are already in serious climate-related trouble. Years of prolonged drought in California have turned the forests of the Sierra Nevada and North Coast into “tinderboxes of highly combustible debris,” according to a recent New York Times article. In Canada, forest fires and industrial development have destroyed almost two million acres of boreal forest since 2000.
“The carbon in a forest is more vulnerable than carbon underground,” Houghton said. “There is a danger in fixing all our problems by adding more forests, because if you take that approach but climate goes on changing and it keeps getting warmer, then all you’ve done is fill the world up with fuel, either through disease, insects, or fire and drought.”
Despite the complications associated with reforestation, Houghton argues that fully committing to reforestation — and ending deforestation — is a crucial piece of the climate puzzle. According to the Global Carbon Budget, which charts the amount of greenhouse gas emissions both released and absorbed globally, land use changes — including both deforestation and reforestation — accounted for about 10 percent of carbon emissions between 2005 and 2014. But, as Houghton notes, those figures really only tell part of the story — while deforestation accounts for around 30 percent of carbon emissions, reforestation helped sequester 20 percent of emissions.
“ There are large growth emissions and removals and they are larger than that net effect that 10 percent would make you think,” he said. “If I’m talking about the potential of forest management to do something for carbon, we’re not just talking about 10 percent of emissions.”
One of the most crucial solutions, Houghton argues, is to stop deforestation, especially in degraded or young forests.
“If you just let the young forest grow, they are taking carbon out of the atmosphere when they do it,” Houghton said. “If you stop the big releases of carbon that come with deforestation, then you have young forests that can recover and degraded forests that can recover.”
The United Nations has committed to stopping deforestation through Reducing Emissions from Deforestation and Forest Degradation (REDD) programs, which seek to create financial incentives for forest management practices. Those programs, however, are not without controversy — many indigenous groups have criticized REDD for allowing polluters like fossil fuel companies to continue extracting and burning fossil fuels by paying for reforestation elsewhere, something that activists have argued is a false solution to the climate crisis.
In the United States, the USDA is trying something similar by encouraging the growth of the tall wood building industry, wherein skyscrapers would ultimately be built out of timber instead of steel and concrete. Secretary of Agriculture Tom Vilsack has praised the industry for offering forest managers a way to use diseased and dying trees before they burn in forest fires, ultimately storing the carbon from these forests inside of buildings rather than releasing that carbon in fires.
But simply ending deforestation or implementing better forest management practices still might not be enough to slow and — ideally — halt global climate change.
“We have to think about putting forests back.”
“I think we have to think a little bigger than REDD. We have to think about putting forests back,” Houghton said.
Part of that means being very deliberate about where and how forests are replanted. As population continues to grow, and available land becomes increasingly scarce, forests will continue to compete with agriculture for land. Some farming techniques, like agroforestry, allow farmers to both grow crops and plant trees. In other places, Houghton argues that marginal land not fit for growing crops should be used as land for reforestation. And while reforestation certainly occurs in urban areas — with side benefits like scrubbing polluted air, cutting the urban heat island effect, and closer project oversight — the shortage of available land in cities makes any large-scale project difficult.
Ultimately, Houghton said, balancing the need for strengthening global forests might force people to make difficult choices, like giving up meat. Deforestation in places like Brazil has been especially driven by the meat industry, which requires large clearings of land to grow animal feed or graze cattle. And while deforestation had been on the decline throughout Brazil, weakened regulations and an increase in global demand for meat has caused an uptick in deforestation in recent years.
“Pasture and range land cover huge areas — not all of those would grow back forests, but some were carved out of forests,” he said.