Charles Darwin, a Victorian biologist, made an important observation more than 150 years ago: that species planted together can often grow stronger than those planted separately.
Ironically, it took a century and half to get an oak to bear fruit and a climate crisis for policymakers to recognize Darwin's idea and make it a priority to plant trees.
For atmospheric carbon dioxide storage and take-up, there is no technology that can match forests. Leading academics who study climate change and forests are now exploring Darwin's idea to grow many different plants together to increase yield.
Researchers and policymakers from Australia and other countries, including the USA, Canada, Germany and Italy met recently to see if Darwin's idea could be used to create new forests that can store and absorb carbon.
Why not plant more forests?
While planting more forests can be a powerful tool to mitigate the climate crisis, forests are complex machines that have millions of parts. If tree planting is done poorly, especially if there is not a commitment to diversity of plant species, it can cause ecological damage. Darwin's ideas are now being followed by a growing awareness that forests with the most trees and trees of different ages are the healthiest.
This model promises to increase forest growth by two to four times, maximising carbon capture and maximizing resilience to diseases, rapid climate change, extreme weather, and other threats.
Mixed forests have different nutrients, so each species has access to different sources. This results in higher yields. The stems with thicker stems contain more carbon.
Mixed forests are often more resistant to disease because they reduce the number of pathogens and pests.
Chapter four of Darwin's 1859 classic book On the Origin of the Species contains Darwin's eminent observation. The "Darwin effect", which has been studied extensively, has spawned a vast amount of ecological literature. It is so far outside the mainstream of forestry thinking that little funding has been made to encourage its use.
Darwin famously described evolution as natural selection. This is a process where genes adapt to their environment. The planet is suffering from human-induced environmental changes that have outpaced the evolution of genes to support larger organisms.
After careful laboratory work has identified the key genes, modern gene-editing methods direct DNA surgery may speed up things. Only evolution of human behavior can change the carbon cycle. This is why it is so fast and far-reaching that we are able to bring us back within safe limits.
More carbon is captured by trees that are healthier
We discussed the study on Norbury Park estate, central England. It describes how the Darwin effect and climate-sensitive measures have enabled the estate to capture over 5,000 tons carbon dioxide each year. This makes it one of the most carbon-negative areas in the UK. These impressive statistics are not achieved by chance or simply by planting trees in the ground. It takes care and ecological awareness to achieve such remarkable results.
Different ages of trees provide timber that can be harvested and thus steady work, which is in sharp contrast to other methods of forest, where large areas of land are cut and cleared simultaneously.
Like other governments, the UK government has established requirements for large-scale responsible tree planting. These requirements are constantly being updated and improved. It is still a difficult decision to decide which trees should be planted, where they should be planted, and what to do once they have grown.
Although it has been said that it is impossible for a forest to be planted, it should be possible to create a plantation that will grow into a forest for the future. For our climate and biodiversity crises to be effective, sustainable, and just, forests are essential. Darwin has shown us how to do it.
Rob MacKenzie is Professor of Atmospheric Science at the University of Birmingham. Christine Foyer is Professor of Plant Sciences at the University of Birmingham.
This article was republished by The Conversation under Creative Commons. You can read the original article.
