In the early 90s, I purchased Bill Mollsion’s book, A Practical Guide for a Sustainable Future. In Chapter 6, Bill explains how important the tree canopy is to the ecology of the forest. He discusses the influence of mature trees to influence the surrounding rainfall and ecology (p. 137-151). He also talks about guilds, plants which live in close association and have a symbiotic relationship.
Research carried out by Dr. Suzanne Simard from the University of British Columbia over the last 30 years has demonstrated that trees not only communicate with each other, they can support each other by passing carbon to each other. Suzanne has also found that Mother trees, the mature forest trees, nurture their own offspring by providing them with more carbon that surrounding neighbours.
Simard, S 2014, TED-Ed talk: The Networked Beauty of Forests, viewed on 29 September 2016, https://youtu.be/dRSPy3ZwpBk
CBC 2016, Talkin’ Trees, viewed on 29 September 2016 [originally viewed on Facebook post], http://www.cbc.ca/radio/quirks/quirks-quarks-for-september-24-2016-1.3774759/talkin-trees-1.3774946.
Mollison B 1990, Permaculture: A practical guide for a sustainable future, Island Press, Washington DC.
Simard, S 2016, Ted Talks: How Trees Talk to Each Other, viewed on 29 September 2016, https://youtu.be/Un2yBgIAxYs