Planting trees. The right thing to do today?
We all know the iconic picture of two hands holding some soil with a young tree sapling sprouting from it. Is that what we need to do today?
In many developing countries it is common to refer to forests as timber. That was the case in the West too. The ‘woods’ and ‘wood’ are basically the same word because wood is the economical activity that comes out of the.. woods.
With the carbon offset market developing and the strong link with carbon sequestration done by trees, forests are now more commonly referred to as a bunch of trees. That is an upgrade. But trees are interchangeable, almost a commodity even. We need a second upgrade.
The good thing is that the narrow focus on carbon is being criticized more often and that expectations towards a broader biodiversity or ecosystem services market are growing¹. From trees to ecosystems. It makes sense. Whereas all forests in the world may look like a large collection of a bunch of trees, there is an important distinction between primary and secondary forests.
Primary forests are high in biodiversity and still have a natural balance between the many species that inhabit them. You cannot replant such a thing. True, if you cut a few hectares, they’ll probably just grow back. But if you do that too often too fast, or you cut too much at once, then species get extinct, the water cycle gets disrupted and the precious soil erodes. It is ridiculous to think that we can just plant it back, or plant it elsewhere. Where will the animals come from? Will you re-plant the fauna as well?
Primary forests are not a global collection of trees. They are actually a puzzle of many small and unique ecosystems. Once gone, they cannot come back. And they disappear at a rate of roughly 10,000 hectares per day². That’s a square of 10km by 10km every day. We cannot plant ecosystems back, so why are we planting now? We need to conserve first what we still have. We must replant after. The only situation in which we support replanting today is for cases where a natural buffer is planted around a threatened primary forest or to halt desertification.
There may also be a perverse side effect of planting trees: the idea that you can destroy here and replant somewhere else.
We are not against planting trees; quite the opposite. Every additional tree is important (on the condition that this tree makes sense in its ecosystem context). But when it comes to allocating resources, we do believe planting trees should not be presented as the priority. The priority is protecting existing primary forests and in some cases, planting trees can support that goal. Once primary forests stop declining, the focus can shift to replanting. There should also be clarity on the fact that you are never replanting the actual ecosystem. What you replant is a B-version of what once was. If we ignore the species that get extinct in the process, it will still take about 4,000 years to grow back to its native state³. A simple walk through the average secondary forest after you have been in a primary forest before will make you hear how different it is. That is because about 80% of biodiversity richness can be measured and deduced from the sounds a forest produces, mostly birds. Secondary forests are remarkably more quiet, which gives away the tragedy they went through.
Forests went from wood to trees, and we’ll go from trees to ecosystems. That means you can plant as many trees as you want, you cannot replant an ecosystem.
(2) Calculated based upon data from: https://news.mongabay.com/2020/06/how-much-rainforest-is-being-destroyed/
(3) https://www.newscientist.com/article/dn14112-how-long-does-it-take-a-rainforest-to-regenerate/
