What Plant-a-Tree initiatives can you name? Every time you use our credit card, we’ll plant a tree. Purchase our product, we’ll plant a tree. Major environmental organizations push tree planting, and why not, right? The message has been driven home to us: plant a tree to save the planet.
But is the actual practice that simple?
How Do Forests Sequester Carbon, Anyway?
The UNECE, the food and agriculture arm of the UN, explains that forests sequester carbon by capturing carbon dioxide from the atmosphere through pores in their leaves. They store it in their branches and trunks and transforming it into biomass through photosynthesis. Sequestered carbon is then accumulated in the form of biomass, deadwood, litter, and in forest soils.
Up to 45% of the carbon stored on land may be tied up in forests.
That ability to collect CO2 is why forests are often called carbon sinks. A carbon sink absorbs more carbon than it releases. These sinks are very important in keeping the levels of carbon dioxide in the atmosphere at manageable levels.
Forests and their role in the carbon cycle are affected by changing climatic conditions. Forest management activities have the potential to influence carbon sequestration by stimulating certain processes and mitigating impacts of negative factors.
So, back to the “plant a tree to save the planet” philosophy. What’s wrong with it? If humans have disrespected, misunderstood, and devalued the role of forests in important carbon sequestration, isn’t planting trees to replace those that have been lost a very good thing?
The answer is yes, and no.
Done well, a mass tree planting initiative can begin to restore a damaged ecosystem. If complemented by a massive transition to renewable energy, trees have a lot to offer as a natural solution to carbon reduction.
But when done poorly, the plant a tree projects can exacerbate issues like stormwater runoff, biodiversity loss, or soil depletion.
A transplanted tree needs attention in the days, weeks, and months after planting — inattention can negate the entire altruistic effort to plant a tree to save the planet.
Disagreements on what types of trees are best for the plant-a-tree projects are rampant. Is it large scale tree farms for massive carbon storage and timber, even though biodiversity may be lost? Is it planting fruit trees to provide food supplies? Is it important for a landscape to be left fallow to permit native species to regenerate?
“It’s kind of the Wild West,” Forrest Fleischman, a professor of environmental policy at the University of Minnesota, told the New York Times.
Know Your Native Trees
The planet is home to nearly 60,000 tree species and more than 3 trillion trees. But that number is rapidly shrinking, as the planet is losing 15 billion trees a year to toilet paper, timber, farmland expansion, and other human activities.
Globally, only a tiny fraction of tree species are widely planted, even though, in 2021 alone, billions of trees were planted around the world. Some of the efforts were winners, reestablishing a forest that had been eradicated, generally for commercial purposes.
But trees have a particular ecosystem that they need to survive and thrive. Not any tree is suitable for any climate, nor can a tree necessarily be planted in any season.
Planting the wrong trees in the wrong place can actually reduce biodiversity by speeding extinctions and making ecosystems far less resilient. One of the challenges with the idea to plant a tree to save the planet is that emphasizing that biodiversity doesn’t provide a financial reward — not like carbon storage or timber markets, anyway.
A native tree is a species that was growing here before the arrival of Europeans. Native tree species can create natural corridors or islands in the urban landscape for migrating wildlife. Many species of wildlife do not recognize non-native species and cannot use them for food or shelter.
Tree planting that carpets large areas with commercial, nonnative species in the name of fighting the climate crisis store carbon but provide little support to the webs of life that once thrived in those areas.
Newly planted trees need lots of TLC, too. Vox reported last year how, after a tree planting project in Turkey, less than three months later, up to 90% of the saplings were dead. The trees were planted at the wrong time, and there wasn’t enough rainfall to support the saplings.
Trees are part of a wider ecosystem that define the habitat of a site. Planting a mixed range of trees can:
- provide shelter and food to a range of species like birds, animals, insects, and fungi
- protect trees from diseases
- provide flood protection and slope stability
- help native tree species survive
Commercial but non-native trees can create a sterile environment, absent the birds, butterflies, and small and large mammals that are crucial elements of original ecosystems.
“They’re planting the same species all over the world,” said Meredith Martin, an assistant professor of forestry at North Carolina State University. Dr. Martin found that nonprofit tree planting efforts in the tropics tend to prioritize the livelihood needs of people over biodiversity or carbon storage. Over time, she said, these efforts risk reducing biodiversity in forests.
Native trees are well-adapted to the local climate, which means they have the best chance at survival. They often don’t have as many pest problems as non-natives, and they also generally leaf out later and drop leaves sooner than non-native species. This allows the sun to reach the understory of the tree for a longer period, allowing low growing plants to perform better. They are very well suited to a particular climate and soil type and, once established, require much less water and nutrition than non-native species.
A viable approach is to start with fast-growing tree species to preserve surrounding native forests then to strategically add native species. Tree farms with this underpinning ideology can help biodiversity by creating wildlife corridors to link disconnected habitat areas.
Final Thoughts about the Practice to Plant a Tree to Save the Planet
Excess carbon in the atmosphere is due today to industrial fossil fuel burning in western societies over the last nearly 300 years. Burning fossil fuels has been devastating to the environment.
Sure, trees help, as they retain carbon. Anthropogenic (human-caused) forest activities like harvesting, fires, and deforestation also expel carbon and are contributing to the environmental havoc.
More than 100 world leaders promised to end and reverse deforestation by 2030, in a COP26 climate summit major deal. It is hopeful, as the commitments include reinforce the role of indigenous people in protecting their trees. Studies have shown that protecting the rights of native communities is one of the best ways of saving forested lands.
Let’s keep our fingers crossed that the COP26 deal can be part of other conversations about removing the link to deforestation from consumer goods sold in developed countries.