There’s perhaps no act more synonymous with environmentalism than planting trees. From the symbolism of cupped hands holding a tree seedling every Earth Day to the linguistic appeal of “‘tree-huggers” — planting trees is rooted in our popular imagination, practically inseparable from the concept of “going green.”
But what if planting trees isn’t as good for the planet as we believe? A growing number of experts are pointing out the problems with some tree-planting campaigns — many prioritize quick-growing trees over the kind that foster biodiversity while others fail to lock in a commitment to keep the land untouched.
According to Dr. Lanhui Wang, a researcher at Lund University who just published a new environmental analysis in Nature, tree-planting can only get us so far. In order to truly align our climate action with deeper commitments to sustainability, we need a stronger approach — rewilding.
Rewilding is the act of restoring land to its uncultivated status. Be it a bog, a prairie, a marshland, a forest or a jungle, rewilding tends to result in more long-lasting and resilient landscapes.
Wang’s research suggests rewilding is more effective than tree-planting, and when it comes to which land to rewild, the answer is also clear: farms.
Humanity uses a lot of land to make food — 46 percent of all of Earth’s habitable land is used for agriculture. Cities, roads, settlements and villages make up just one percent, in fact. And of all the land used for agriculture, feed crops, meat production and dairy facilities make up the lion’s share — more than three-fourths of farmland is currently used to produce foods sourced from animals.
Cutting back on how much meat we eat could boost rewilding efforts, says Wang, who points out that if we produce less meat, we would free up a whole lot of land. If all meat products were replaced by plant-based alternatives, some researchers estimate that a whopping 75 percent of agricultural land could be returned to actively help – rather than harm – both animals and the ecosystem.
Considering the toll animal agriculture takes on the planet, the more that we can rewild of this kind of farmland, the better.
Planting Trees Isn’t Enough
Many environmental organizations use tree-planting as a quantifiable metric for helping the ecosystem. Ecosia, the green search engine, has a handy tree-planting counter, and many other groups – One Trillion Trees, the 22 Million Tree Pledge, the 10 Billion Trees Tsunami — are all named after the number of trees they want to protect or plant.
Tree-planting projects do have their place. Some have been shown to mitigate desertification in prairies and improve pollution in cities. Agroforestry, the act of integrating native trees in agriculture, can help improve carbon sequestration, and nourish local communities.
There’s also no question trees act as carbon sinks — sucking up carbon out of the atmosphere — and afforestation projects can be beneficial. Afforestation is the act of planting trees where they did not exist previously, while reforestation means restoring former forests to their original glory. But they aren’t the same thing — and they don’t offer the same benefits.
Both reforestation and afforestation have the same environmental trump card — carbon sequestration. Trees are great for sucking carbon from the atmosphere (which is going to be a critical part of any climate change mitigation strategy) but some tree-planting projects are designed in such a way that they don’t help biodiversity. Sometimes, in fact, they can even hurt it.
Take Ireland. The country historically boasted a tree cover that sprawled over four-fifths of the country, but now, trees occupy a meager 11 percent. The government has made a goal to reach 18 percent by the mid-century, in order to help combat climate change.
At first, the government chose Sitka spruces. They’re cheap and easy to plant. They mature within 30 years — ideal for trapping carbon quickly. But they’re native to North America, not Europe. The branches aren’t suitable for many of Ireland’s endangered bird species, like hen harriers or curlews. The canopies are also so dense that sunlight can’t reach the forest floor, suffocating any native flowers, bushes or vines that had the misfortune of being planted in a Sitka forest monoculture. The leaves sucked in carbon, yes, but at the cost of biodiversity.
According to Wang, situations like Ireland’s aren’t uncommon. Planting a single tree species “[leads] to a lack of biodiversity and increased susceptibility to environmental stresses.”
There can be other problems with afforestation too. Afforested plots are easily razed for lumber, which is why some tree-planting schemes end up as little more than greenwashing. When plots are only forested for a few years and then sold to private corporations for harvest — the project is no longer storing carbon. Worse, if the tree-planting scheme was intended to offset climate pollution it had to stick around for 100 years, at least, since that’s the amount of time carbon lasts in the atmosphere. Now, the offset is worthless and we’re stuck with more pollution.
Choosing quick carbon capture over biodiversity and ecosystem symbiosis is quite literally missing the forest for the trees. There has to be a better solution.
Rewilding Offers a Better Alternative
Reforestation is a more powerful strategy, both for storing carbon and replenishing wildlife.
Rewilded ecosystems tend to be more reliable and less susceptible to Mother Nature’s destruction. The more heterogeneous and diverse an ecosystem is, the more likely it can endure temperature extremes and its dangers, like forest fires or extreme weather events. Restoring a disappearing forest prevents erosion, species extinction and biodiversity loss before they throw the ecosystem out of balance.
Introducing animals into the ecosystems also helps. When grey wolves were reintroduced to Yellowstone National Park in 1995, the entire ecosystem changed for the better — beaver populations flourished, willow trees became hardier and ravens changed their flight patterns. You just can’t get that same biodiversity boost by planting row after row of the same species of trees.
To the average passerby, rewilding might not look all that different from afforestation — both lead to more tree-planting after all. But rewilding is different — it requires us to reintroduce native species and make changes appropriate to the terrain itself – whether it be a marsh, bog, grassland or jungle.
Farms: A Sprawling Opportunity
The vast global acreage of industrial farmland presents the perfect canvas for this rewilded and much greener future.
Farms already tend to be located near the wild landscapes they used to look like. “They are often situated in areas with a history of natural habitats, such as grasslands, forests or wetlands” says Wang. And on a practical note, farmland is usually cheaper and more convenient to buy than planting new forests, which also makes them prime targets for rewilding.
Even though food production rates are on the rise, farmers are abandoning land at increasing rates, as land becomes overused and “farmed out.” In the European Union for instance, about 20 million hectares of land are likely to be abandoned sometime this decade — that’s an area bigger than France.
At the same time, many countries in Europe are beginning to shift their diets away from meat to curb the harmful effects of animal agriculture. In Germany, meat consumption has declined by over 12 percent this decade, with rates plateauing in other countries like the Netherlands and the UK as well. In the EU, meat consumption is expected to fall by nearly four percent over the next decade.
These dietary shifts are a huge and necessary part of climate action — they free up land and reduce carbon emissions — and rewilding campaigns are the next critical step that follows.
One of Wang’s favorite examples is Rewilding Britain, a campaign that prioritizes natural “corridors” — huge swaths of land that connect protected areas and allow animals to move freely from one space to another. One member project aims to restore carbon-rich peatland while protecting bogbeans and short eared owls, for instance.
When it comes to planting trees, it’s important that we get it right. According to a 2021 UN report, we need to collectively rewild nearly a billion hectares of degraded land in order to combat climate change — a land mass about the size of China. And with researchers predicting we’ll bust through that critical 1.5C climate threshold in the next four years, we have no time to waste.
Björn Jóhann Ólafsson is an Icelandic-American writer who examines the psychology of eating animals, the environmental footprint of the meat industry, and the plant-based meat industry. He lives in Spain with his two lovebirds.