Protecting old-growth forests slows down biodiversity loss
More than 20,000 species of organisms live in Finnish forests. A few dozen of these are tree species. We must be able to guarantee that as well as the trees, another 20,000 species are also able to continue living in our forests.
Research shows that there are 833 endangered forest species. Nearly half of these are invertebrate. There are also many endangered species of fungus and lichen. The more demanding forest species are more likely to survive is we let them live in peace, meaning that the forest is not cut down.
Protecting old-growth forests is an effective way of fighting biodiversity loss. Protecting forests also reduces the nutrient loading of the rivers and lakes, which is the reason the Finnish Natural Heritage Foundation launched its Raakkumetsä campaign, which aims to protect the freshwater pearl mussel.
Protecting old-growth forests is good for the climate
In terms of fighting climate change, the main issue is whether the carbon dioxide is in the atmosphere or stored somewhere else. As a forest grows, it is slowly trapping carbon dioxide, but after the trees have been felled, the carbon dioxide is quickly released, which only takes a few years in the Finnish industry. This means that the most important impact that the forest has on the climate is in storing carbon dioxide.
In an old forest, just the roundwood often has a volume of more than 400 cubic metres per hectare, whereas the average for commercial forests is approximately 100 cubic metres per hectare. One cubic metre of wood stores approximately 1000 kilos of carbon dioxide. When an old forest is protected, this keeps many times more carbon dioxide out of the atmosphere than a commercial forest.
The amount of carbon that is accumulated by a tree depends most on the number of chloroplasts, which are the photosynthesising organelles. A large tree has much more green in it than a small one. That is why a large tree traps more carbon dioxide than a small one. This can be confirmed by looking at the growth rings, because volume can sometimes be misleading.
The thin, 0.3-millimetre growth ring which a large tree achieves over a year contains ten times more carbon dioxide than a smaller tree with a 3-millimetre growth ring. And Finnish trees can continue to grow for hundreds of years; pine trees up to five hundred years. So protecting old-growth forests makes Finland’s carbon sinks more effective.
The forest soil also stores at least the same amount of carbon as the trees, and often much more. After clear-cutting and tilling, the carbon dioxide stored in the soil is released. The amount of carbon is larger than that contained in the trees of a forest ready for felling. In an old-growth forest, the dry peat is very thick, and the amount carbon accumulated over thousands of years is at its highest.
Old-growth forests are good for people – and the whole planet
Old-growth forests offer varied and interesting locations for hikers, inexhaustible sources of inspiration for artists, and an indispensable place of learning for all. In the old-growth forest, everyone can see and experience nature’s cycles and diversity. In the midst of large trees, tufts of moss, decayed wood, babbling brooks and wetlands, one can often feel small in a positive way.
Deep in the shade of the forest, your senses can slowly start to perceive that there are many of us here – thousands of different animals, plants and fungi, each with their own needs and place in the world. At best, this realisation can lead to a deep respect for nature. Old-growth forests can turn people into environmentalists, and that is why it is important for the shared future of all living organisms to protect them.
Words: Anni Kytömäki and Risto Sulkava (climate text)