Simard identified 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. A mother tree supports seedlings by infecting them with fungi and supplying them with the nutrients they need to grow.^[8]

She discovered that Douglas firs provide carbon to baby firs. She found that there was more carbon sent to baby firs that came from that specific mother tree, than random baby firs not related to that specific fir tree. It was also found that the mother trees change their root structure to make room for baby trees.^[9]

Her book Finding the Mother Tree asserts that forest ecologies are interdependent with fungal mycelium. She asserts that trees (and other plants) exchange sugars through their respective root systems and through interconnected fungal mycelial structures to share (and at times trade) micronutrients.^[10][11] This is significant in terms of the way existing woods and forests are managed and new plantations established.^[12]

Simard found that "fir trees were using the fungal web to trade nutrients with paper-bark birch trees over the course of the season".^[13] For example, tree species can loan one another sugars as deficits occur within seasonal changes. This is a particularly beneficial exchange between deciduous and coniferous trees as their energy deficits occur during different periods. The benefit "of this cooperative underground economy appears to be better over-all health, more total photosynthesis, and greater resilience in the face of disturbance".^[13][14]

Suzanne Simard is an advocate of science communication. At the University of British Columbia she initiated with colleagues Dr. Julia Dordel and Dr. Maja Krzic the Communication of Science Program TerreWEB,^[15] which has been training graduate students to become better communicators of their research since 2011. Simard has appeared in videos intended for general audiences, including three TED talks,^[16][17] the short documentary Do trees communicate?,^{[18] [19]} and the longer documentary films Intelligent Trees^[20] (where she appears alongside forester and author Peter Wohlleben) and Fantastic Fungi.^[21] New Scientist magazine interviewed Simard in 2021.^[6] Suzanne Simard has published a book where she reviews her discoveries about the life of trees and forests along with autobiographical notes.^[12]

Simard discussed her work and her book Finding the Mother Tree on BBC Radio 4's Woman's Hour in March 2022.^[22]

Simard's life and work served as the primary inspiration for Patricia Westerford, a central character in Richard Powers' 2018 Pulitzer Prize winning novel The Overstory, in which Westerford pioneers the controversial idea that trees can communicate with each other, and is ridiculed by fellow scientists before eventually being vindicated.^[23][24]

Simard's work was referenced in Season 2, Episode 11 of the Apple TV+ series Ted Lasso when Coach Beard says: "You know, we used to believe that trees competed with each other for light. Suzanne Simard's field work challenged that perception, and we now realize that the forest is a socialist community. Trees work in harmony to share the sunlight."

In 2022 Simard appeared as a panelist in Canada Reads, advocating for Clayton Thomas-Müller's book Life in the City of Dirty Water.^[25]

Finding the Mother Tree: Uncovering the Wisdom and Intelligence of the Forest, Penguin, ISBN 978-0141990286, (2022)

• Frederic Clements – an earlier proponent of cooperative communities of plants
• Ragan Callaway – another modern proponent of cooperation

• Suzanne Simard: How trees talk to each other | TED Talk 2016-07-22 – Introduction video explaining her findings
• “Mother Trees” Use Fungal Communication Systems to Preserve Forests
• Official Trailer "Intelligent Trees" featuring Suzanne Simard and Peter Wohlleben
• The Social Life of Forests
• Wood Wide Web documentary