The Forest Below Our Feet
I have a distinct memory from years ago of a portage we took on a canoe trip in the Boundary Waters Canoe Area Wilderness. I believe the portage was around one of the smaller rapids on the Little Indian Sioux River, upstream of the long portage around Devils Cascade with its dramatic views and scenery, before it empties into Loon Lake, then into the Rainy River on its way to Hudson Bay. One section of the trail ran close to a small waterfall, down in a valley, densely forested with white cedar and spruce.
It must have been the humidity from the falls combined with the stillness of the air, but the scent of the cedar was intense, and not the intensity you get with an artificial air freshener. It was fresh and clean, a rich aroma that filled your senses almost to the point of tasting it.
Healthy forests hold wonder and adventure, they support biodiversity, protect clean water, and provide renewable resources for our use. When most people think of forests, the first thought is of trees. But forests are much more than that, they are communities of plants, animals, insects and fungi, all related and reliant on the soil and water that support them.
Forest soils are fungal dominant, meaning the soil organisms best adapted to cycle nutrients to these woody plants, are fungi. Unlike grass based prairie soils, which rely primarily on bacteria as the primary driver of the soil food web, forest soils are dominated by vast mycelium networks, often forming physical connections with trees and shrubs. These connections are many and complex–hence the idea of the forest below our feet.
One type of fungus vital to forest ecosystems is mycorrhiza, which forms a symbiotic relationship with plants, where the plants, through photosynthesis, provide food to the mycorrhiza and, in turn, the mycorrhizae provide water and nutrients back to the plants. For example, the nutrient phosphorus is a complex mineral which can form tight bonds with soil, often making it unavailable to plants. Mycorrhiza absorbs unusable phosphorus and converts it to a usable form making it available to plants.
Research has shown that trees can exchange nutrients through mycorrhizal connections, with “mother” trees favoring some trees over others in the understory. The understory is the layer of trees and shrubs that occupy the space between the floor of the forest and the top canopy. It’s also been shown that plants can send chemical signals through mycorrhizal connections, warning nearby plants of stressors such as disease or browsing animals.
Sir Albert Howard wrote of this mysterious fungus that benefited plant growth in An Agricultural Testament, published in 1940. His work has long been dismissed by universities and industrial agriculture. However, in recent decades, the concept of this powerful fungus working in symbiosis with trees and other plants is well documented. The Mother Tree Project lists seventy five research papers on the topic.
Forest communities are complex and the implications of management activities, such as logging and grazing, are not fully understood. Forest managers are now looking at how they can mimic natural disturbances when conducting logging activities. Others are looking at how grazing ruminants impacted forests and savanna ecosystems and these types of disturbances could be mimicked to better manage landscapes.
What is a favorite memory you have of spending time in the woods? Can you recall a time when the fresh earthy smell of a forest soil triggered your senses? Join Happy Dancing Turtle on January 10th, for our next Change Exchange, to share your story, and learn more about the life below the forest floor. January through March, the group will meet via Zoom. Learn more here.