Firstly, let’s clear up a few myths:
Myth 1: Trees get rid of carbon
Unfortunately, you cannot get rid of carbon. Trees absorb and break down carbon dioxide, use the carbon part to build themselves taller, and emit the oxygen. This means all the carbon a tree removes from the atmosphere still exists, locked inside the tree – or inside a product made from the tree. If the wood rots or burns, all that carbon is released once more. This also means that when we plant trees to offset our carbon emissions, we make the assumption that the trees will grow to maturity. We’re emitting carbon today and then relying on the trees we plant to absorb it in years to come, effectively taking out a carbon loan – not a great deal for the planet. Given the immediacy of climate change, this reinforces why it’s essential to reduce emitted carbon as much as possible before offsetting.
So, trees don’t get rid of carbon; they only temporarily sequester it as they grow.
Myth 2: Cutting down trees stops them from absorbing carbon
If growing trees absorb carbon, then it’s reasonable to want as many trees growing as possible, and to view any logging as negative. However, like people, most trees grow quickly when they’re young and then plateau when they reach maturity. This means that an old forest with lots of mature trees absorbs relatively little carbon compared to a newly planted one full of young trees. Periodically felling mature trees to plant saplings causes more carbon to be absorbed overall for a given area of forest. Furthermore, felling slow-growing species and planting faster-growing ones will cause more carbon to be absorbed for a given time period.
In summary, cutting down trees can cause more carbon to be absorbed provided you replace them with more young trees, particularly fast-growing ones.
Trees store carbon, but not forever
Given young trees absorb the most carbon, it seems the most productive way to lock in carbon is to treat a forest like a field of wheat – plant an area of identical, fast-growing trees, let them mature, then cut them all down and start again. This technique is called ‘clear cutting’, and from a short-term carbon (and financial) perspective, it’s hard to beat. The trees all grow at the same rate, reaching maturity at the same time, and can be easily felled en masse, then processed and sold. However, a tree farm is not the same as a forest. Monocultures are low in biodiversity, and what little wildlife they can support is devastated on the day it’s all cut down. A tree farm is also not sustainable – the soil nutrient levels become depleted, making each generation of trees progressively less healthy and slower growing, eventually leading to an ecological collapse.
Luckily, there are other options. ‘Continuous cover’ forestry is the process of felling individual trees when they’re mature while maintaining the overall forest cover. This method is compatible with a healthy, biodiverse forest containing trees of varying ages and species, where proportions of dead wood are left to rot as part of the ecosystem. In an ideal world, all logging would be continuous cover, but the process is far less efficient than clear cutting. Due to the added workload required to monitor individual trees across a large area, plus the difficulty of felling trees and exporting timber from within the forest, and a lower output due to the ‘crop’ sharing space with other species, even the most sustainable timber producers usually adopt a hybrid strategy, preserving a portion of their land through continuous cover while clear cutting elsewhere to remain profitable. The new EU Forest Strategy for 2030 states that clear cutting “should be approached with caution.” For the time being, it’s a necessary evil.
In conclusion, cutting down trees in a sustainable manner then replacing them with more young trees is an extremely effective way to remove carbon dioxide from our atmosphere. Building with timber locks this carbon away for decades to come, and every building made this way is a building not made using steel and concrete, both of which have far higher carbon footprints. So is it green to cut down trees? Yes!
Part two will look at the broader humanitarian impact of logging, and how we can make the most of timber as a carbon sink without losing sight of the bigger picture of forest stewardship.