According to Simard, the forest organisms are in effect sharing elements among each other rather than competing for survival. This paints a much more comprehensive and holistic picture of the relationship between plants. Instead of attempting to understand organisms individually, the whole forest must be considered as a single entity that works in concert in order to gain clarity and insight on what is really going on. A picture that contrasts with Darwinian evolutionary sentiments and one that supports the oft-quoted Gaia hypothesis of the earth as a single living being, this particular line of research details a system of communication that closely resembles a neural network like that found in the human brain.
These underground networks can be organized around 'mother trees' -- old, large, well-established trees that appear dominant in the area. The mother tree networks are massive, connecting large numbers of trees and plants from many species into a single structure. This process supports a healthy ecosystem by maintaining and fostering biodiversity as well as its own longevity. As trees connected to the network die, they continue to pass carbon and nitrogen on to others, transferring 'some of their legacy to the new generation.'"
Video Source: http://www.oddly-even.com/2012/06/11/how-trees-communicate-video/