A fascinating theory known as ‘Wood Wide Web’ holds that forest trees can ‘talk’ to each other and even share nutrients and protect their ‘offspring’ through an underground network of fungal filaments. The idea, which arose in the late 1990s from studies showing that sugars and nutrients could flow underground between trees, received a great deal of media attention and became very popular. However, and this is where the fairy tale breaks down, some researchers believe that it lacks scientific basis.
“It’s important for the public to understand that many popular ideas are ahead of science,” says Justine Karst, a professor at the University of Alberta, Canada. Together with two other colleagues -Melanie Jones, from the University of British Columbia-Okanagan, and Jason Hoeksema, from Mississippi, this researcher has published an article in ‘Nature Ecology & Evolution’- in which three popular statements about the capabilities of underground fungi known as common mycorrhizal networks (CMNs), which connect the roots of multiple plants underground.
According to the researchers, while these networks have been scientifically proven to exist, there is no strong evidence that they offer benefits to trees and their newly germinated ‘children’ (seedlings).
For starters, the authors say that the belief that MNCs are widespread in forests It is not supported by sufficient scientific evidence. Not enough is known about this structure and its function in the field, “with very few forests mapped.”
‘Guys, watch out for that plague’
The second statement, that adult trees transfer resources to seedlings through the network and that drive its survival and growth, also proved questionable. A review of 26 studies, including one Karst co-authored, found that while trees can transfer nutrients underground, nets don’t necessarily cause that flow, and seedlings generally don’t benefit from access to the net. Apparently, connecting to the network did not produce more beneficial effects -nor more harmful- to the trees.
The third statement, that adult trees send ‘warning signals’ of insect damage to saplings via the web is also not supported by a single published peer-reviewed field study (other researchers who are experts in a particular field), which is the usual way they report scientific studies.
The researchers say that exaggerated information can shape and distort the public narrative about these networks and that, in turn, could affect the way forests are managed.
“Distorting the science about MNCs in forests is a problem because sound science is critical to making decisions about how forests are managed. It is premature to base forest practices and policies on MNCs ‘per se’, without further evidence. And failing to identify misinformation can erode public confidence in science,” they point out.