• Trees are key for the health of our planet, but belowground ecosystems are equally as important.
  • The health of forests begins underground, where the majority of terrestrial biodiversity is found.
  • Soil is also where the key processes of nutrient cycling and carbon storage occur.
  • It's therefore vital that we consider the entire ecosystem when protecting forests, not just what we can see above ground.

Trees get all the credit. But for a forest, the belowground ecosystem—soil, roots, fungi, and microorganisms—is equally important.

Traditionally, the aboveground ecosystem has been studied more often. According to researcher Whitney Stohr, “Aboveground organisms, tree stands, and the forest floor are immediately identifiable components of a forest ecosystem; one does not typically refer belowground when describing a forest in common parlance.” That’s because “belowground remains, physically and hence metaphorically, out of sight, out of mind.”

Healthy forests are important for a healthy future, and a healthy future begins belowground. Forests account for 70 percent of terrestrial biodiversity, and most of it is found belowground. Furthermore, the majority of a forest’s carbon storage and sequestration, essential for mitigating climate change, happens belowground.

a diagram showing how below ground ecosystems work
The fine root systems of trees are responsible for 75% of forest biomass production.
Image: Wardle, David & Bardgett, Richard & Klironomos, John & Setälä, Heikki & Putten, Wim & Wall, Diana. (2004). Ecological Linkages Between Aboveground and Belowground Biota. Science (New York, N.Y.). 304. 1629-33. 10.1126/science.1094875.

When it comes to forest ecosystem services, or natural benefits, trees often come to mind first: they provide aesthetics, air and water filtration, and habitat. But many of these processes begin belowground. Forests account for 25 percent of the world’s biomass, and the fine root systems of trees are responsible for 75 percent of forest biomass production. This organic matter is essential to soil health and acts as a food source for many different species.

Belowground ecosystems are not just a food source, they are an essential habitat, too. Fifty percent of animal biodiversity is found belowground. The ecosystem below includes bacteria, fungi, and nematodes, to name a few. These often-forgotten ecosystems are more diverse than the aboveground, and these species are responsible for many ecosystems that plants, animals, and humans rely on, including water purification, soil health, and decomposition.

Both nutrient cycling and carbon storage take root in the soil. Nutrient cycling—including the nitrogen cycle and the carbon cycle—largely takes place belowground. These processes influence water health, plant growth, and the sequestration of greenhouse gases. Beyond forests, belowground health strongly influences food production.

Many recent studies have sought to examine how the aboveground and belowground ecosystems interact. Those studies may indicate that when one part of the ecosystem is out of balance, the other will be, too. Stohr gives the example of forest conversion. Converting forests to agriculture can decrease plant diversity and impact nutrient cycling, which in turn affects the food web and biomass inputs into the ecosystem.

Nature

What is the World Economic Forum doing about nature?

Biodiversity loss and climate change are occurring at unprecedented rates, threatening humanity’s very survival. Nature is in crisis, but there is hope. Investing in nature can not only increase our resilience to socioeconomic and environmental shocks, but it can help societies thrive.

There is strong recognition within the Forum that the future must be net-zero and nature-positive. The Nature Action Agenda initiative, within the Platform for Accelerating Nature-based Solutions, is an inclusive, multistakeholder movement catalysing economic action to halt biodiversity loss by 2030.

Dynamic and flourishing natural ecosystems are the foundation for human wellbeing and prosperity. The Future of Nature and Business report found that nature-positive transitions in key sectors are good for the economy and could generate up to $10.1 trillion in annual business value and create 395 million jobs by 2030.

To support these transitions, the Platform for Accelerating Nature-based Solutions has convened a community of Champions for Nature promoting the sustainable management of the planet for the good of the economy and society. The Nature Action Agenda also recently launched the 100 Million Farmers initiative, which will drive the transition of the food and agriculture system towards a regenerative model, as well as the BiodiverCities by 2030 initiative to create an urban development model that is in harmony with nature.

Get in touch if you would like to collaborate on these efforts or join one of our communities.

Stohr proposes several avenues to bring greater awareness to the belowground. First, more research funding can expand our current knowledge of these ecosystems and why they matter. This can lead to policies that protect the entire forest ecosystem, not just the trees. Stohr concludes, “Effective decision making at the scientific, policy and global level can increase current focus on belowground ecosystems and positively advance scientific research and available funding for ecological restoration of the complete forest environment.”