Underneath every group of trees and forest is a complex network of bacteria, fungi, and roots that the plants use to communicate and support each other. This incredible web has become affectionately dubbed the ‘wood wide web’. In a world first, researchers have created a map of this secret underground world.
Scientists from the Crowther Lab at ETH Zurich, Switzerland, and Stanford University in the US used the Global Forest Initiative database and machine learning to create models of the network. The GFI’s database includes more than 1.2 million forest tree plots with 28,000 species, from more than 70 countries.
Effects of climate change clear
"It's the first time that we've been able to understand the world beneath our feet, but at a global scale,” Prof Thomas Crowther, one of the authors of the report, told the BBC. The research also highlights how mycorrhizal networks are susceptible to the effects of climate change as well as how they can be a tool to help understand what is happening to plants as the planet heats up.
"What we find is that certain types of microorganisms live in certain parts of the world, and by understanding that we can figure out how to restore different types of ecosystems and also how the climate is changing,” Crowther explains. Mycorrhizal fungi form a symbiotic relationship with plants.
Types of fungi changes with temperature
There are two main types: arbuscular fungi (AM) that penetrate the host's roots, and ectomycorrhizal fungi (EM) which surround the tree's roots without penetrating them. EM fungi are more often found in temperate and boreal systems, these fungi are more susceptible to climate change but play a huge role in helping lock up carbon from the atmosphere.
AM fungi are found more commonly in the tropics, promote fast carbon cycling. The research shows that currently around 60% of the world's trees are connected to EM fungi, but as global temperature rise these fungi and their trees will die and be replaced by more tropical species and AM fungi. This is a problem as less and less carbon will be stored by the tree and fungi system.
UN set to plant a trillion trees
Scientists estimate that if there isn’t a global reduction in carbon emissions by 2100, there could be as much as a 10% reduction in EM. This in combination with other recent research into mycorrhizal networks will serve as the fundamentals for the UN's trillion tree campaign.
The research will help the UN dictate which tree species should be planted there to ensure the maximum amount of mycorrhizal network is generated. The project will help ensure that carbon continues to be locked down underground. Understanding the complexities of forests and their associated fungi are integral to that happening.