The trouble with forests
To The Guardian
Tree planting may have “mind-blowing” potential to tackle the climate crisis. However, the climate crisis is only one symptom of our continued destruction of the planet. The climate crisis has barely got going, but we are already in the midst of an extinction crisis that could soon rival that of the Cretaceous, when the dinosaurs became extinct. Today, we are losing species at a mass extinction rate, and at this point it’s nothing to do with climate.
Planting billions of trees will accelerate the extinction crisis, because closed-canopy forest is not the natural state of most areas of continents. During the ice ages, and the intervening interglacials that dissected them, areas that we regard as natural forest today weren’t closed canopy, but instead were savannah or steppe, habitats that also absorb and store a great deal of carbon.
Covering these areas with closed-canopy forest will reduce biodiversity and condemn many species to extinction – species that still survive in the remaining fragments of these habitats, or in the farmland that we have replaced them with. Planting billions of trees may be one way of solving the problem, but will create more. Perhaps we can just produce less carbon in the first place. We have the technology, and we know how to make it work.
Martin Dohrn, Bristol
To The Guardian
Your article reinforces the idea that the only way to get a tree or forest is to plant it. Creating woods in the way promoted by Defra grants and the Woodland Trust results in serried ranks of trees in plastic tubes that are often left long after they should be removed. Planting saplings grown abroad is almost certainly how ash dieback came to Britain.
Any piece of land, anywhere in the world below the treeline, left alone without any human interference or expense, will undergo a natural growth via scrub to a fully mature forest of properly native trees. As it does so, it will be taking lots of CO2 out of the atmosphere.
Whether the new forest is planted or natural, when it is mature it no longer has any good effect on CO2 levels: the rotting dead leaves and fallen trees release exactly the same amount of CO2 as the trees take in by photosynthesis.
To make a mature forest a contributor to CO2 reduction you need to cut down the mature trees and use the wood for building (or burn it to replace fossil fuels). Then let the felled forest regrow.
Dr David Corke, director, Organic Countryside CIC