I’ve often been approached by frustrated people who want to know more about climate change, deforestation and ways in which they can help out with these issues. When confronted with such an overwhelming amount of information and news, most of us feel baffled. And of course, we feel eager to help and do something, right?
So we look to the internet and our trusted sources to learn more about the solutions that are within our reach, and we eventually come across a very popular one: tree planting as a way to recover ecosystems and offset our carbon emissions.
And don’t get me wrong here. Tree planting is an absolutely necessary aspect of our road to planetary recovery. But it isn’t the only solution. And, by itself and if not done properly, it will just not do. In fact, it can sometimes cause more harm than good.
Context Matters
We absolutely need to be mindful of two things when it comes to this issue: the importance of context and of protecting standing rainforests. Let me explain why.
Let’s talk about context first-- biological context. This refers simply to knowing where and how trees are going to be planted.
Think of it this way: ecosystems have evolved for millions of years, adapting to very particular conditions over time, and resulting in the mosaic of trees, plants, and animals that we see. That context has to be respected if we want to restore ecosystems.
For instance, take the Redwood National Parks in California. These forests are delicately balanced ecosystems that support a very particular array of plants and animals, like redwoods, oaks, beeches, maples, bears, deer, and owls.
Imagine that we lose a part of these parks to deforestation and we want to plant trees in nearby lands to restore them. It wouldn’t make sense to plant one million palm trees and call it a day, right? We’d instead have to mimic the naturally occurring species distribution, planting redwoods, maples, beeches, and oaks, in a proportion that is similar to the one we find in the original old-growth forests.
We’d also have to take care of these trees for a while, making sure they get enough water and sunlight, and protecting them against pests. And then, after these trees begin to grow, we’d start to see some animals and, eventually, we’d end up with a functional ecosystem that would look a lot like the forest we were trying to recover.
If we instead plant a plot full of palm trees, we’d end up with pretty much the same situation we started with: barren land with no trees. Or worse, we could end up creating large imbalances in the original ecosystems by introducing species that have never coexisted with the native ones.
We can't afford to overlook standing forests
Now, let’s go to the second point: why standing rainforests absolutely have to be a part of the equation.
First, let’s talk about the big difference that exists between tree planting and standing forest protection when it comes to carbon.
Many tree-planting efforts are aimed at offsetting carbon emissions, but oftentimes, this isn’t the best strategy, since mature forests, and especially rainforests, are much better at storing and absorbing carbon than juvenile trees.
A mature tree has more surface area to absorb carbon because it has more leaves that are actively photosynthesizing and turning carbon from the atmosphere into organic compounds. Additionally, mature trees have a much larger volume on which they are already storing carbon, since the carbon that trees fix is stored in their tissues, like their branches, leaves, roots, and trunks. So a tall, thick tree stores a lot more carbon all over its volume than a thin, small tree. It is also possible that the rate at which they fix carbon is different.
So, to summarize all of this, if you want to absorb carbon with small trees, you'd need way more trees and way more time.
Another thing to consider is that juvenile trees don't always survive after being planted, and it takes them a long time to become mature, carbon-rich trees. Over that time period they can be cut down, and their carbon can be released back into the atmosphere. So planting trees is overall not nearly as effective in compensating carbon emissions as protecting standing forests with mature trees.
And this isn't considering all the other aspects and processes that are part of a complete, functional ecosystem like a rainforest that help to fix carbon and keep it in place, like soil microorganisms, decaying organic matter from dead animals and plants, nutrient cycling, etc. When tree-planting projects plant trees in a monoculture-like way, these vital processes that exist in natural ecosystems are often ignored, creating unstable conditions for the trees to grow in and limiting their carbon-absorption potential.
