This commentary is by Ron Krupp, author of “The Woodchuck’s Guide to Gardening,” “The Woodchuck Returns to Gardening” and his forthcoming book, “The Woodchuck’s Guide to Ornamentals & Landscape Plants.”
I recently saw an inspiring YouTube video called “Mother Tree” by Suzanne Simard, a Canadian forest ecologist. Simard’s research focuses on how fungal organisms living in soil help trees establish forest communities.
Fungi live inside the roots of trees and form mycorrhizas (literally “fungus-roots”). These fungi help trees acquire nutrients and water from the soil in exchange for carbon. These mycorrhizal associations are highly complex and dynamic, a result of the great diversity of mycorrhizal fungi, hosts, and terrestrial systems that interact and evolve with changes in hosts and environmental conditions
In 1997, Simard was part of a team of researchers that discovered that trees were connected to one another through an underground web of mycorrhizal fungi. This network allows trees to communicate by transferring carbon, nutrients and water to one another.
Simard helped identify something called a hub tree, or “Mother Tree.” Mother trees are the largest trees in forests that act as central hubs for vast below-ground mycorrhizal networks. They support young trees or seedlings by infecting them with fungi and ferrying them the nutrients they need to grow.
Fungi help plants uptake soil nutrients in exchange for sugars produced by the plants. In forests, mycorrhizae form long strands called hyphae that run between trees, acting as connectors. This giant underground transportation network is called the “common mycorrhizal network.”
Scientists have long known that mycorrhizal fungi — those that live symbiotically in and on the roots of plants — trade minerals and water they absorb from the soil for food that plants manufacture from sunlight, carbon dioxide and water. A tree’s root system with mycorrhizae has more area to absorb water, which aids trees being able to withstand drought conditions.
The host plant provides the mycorrhizal fungi with carbohydrates (carbon) from photosynthesis. A substantial portion of this carbon is ultimately transferred to the rhizosphere and is estimated to account for up to 15 percent of the organic matter in forest soils.
Natural undisturbed forests can be the perfect example of nature at its best. One may ask, how does all that diversity of plant life survive without nutrient inputs, scheduled watering, or routine pruning? There is an underground symbiotic relationship that is responsible for sustaining this ecosystem, a partnership between plants and mycorrhizal fungi that has been in place for hundreds of millions of years.
As I stated earlier, forests take in carbon dioxide through the atmosphere to make energy through photosynthesis. Trees then use this energy to maintain themselves and grow. Through this process, trees capture carbon in the form of wood and other organic matter, such as leaves.
In fact, half of a tree’s weight consists of stored carbon. Since more than 80 percent of New England is forested, our landscape plays an important global role in both sequestering and storing carbon, ultimately helping to reduce the impact of climate change. Most of New England’s forests are privately owned and thus they will have the greatest impact on the amount of carbon absorbed from the atmosphere. We are blessed.
Trees
I think that I shall never see
A poem lovely as a tree.
A tree whose hungry mouth is prest
Against the earth’s sweet flowing breast;
A tree that looks at God all day,
And lifts her leafy arms to pray …
— Joyce Kilmer, 1913
