“Old growth forests like Broceliande, whether enchanted or not, are complex, diverse ecosystems which seem to embody the idea of balance and harmony”
– Sharon Blackie
Trees, even those to appear to stand solitary, are never alone. They are a hive of activity filled with a city of residents and passers through. There are birds, mammals, insects and fungi, all of whom have intricate, intimate relationships with that tree.
Trees have mutualistic relationships with bacteria, fungi and animals. Trees orchestrate other lifeforms and shape the very environment they live in.
For the birds, the tree is a source of food, a shelter, a place to raise your young and a nursery and play area. For mammals, the tree can be sanctuary, a place to hide from the rain. For insects, the tree is pollen and leaves, as well as home. For fungi, the tree is part of an amazing web.
This amazing, hidden connection is fascinating. Trees and fungi have a symbiotic relationship where the fungi connects the trees together. The trees can then use the fungi to direct resources from thriving trees to those which are more vulnerable, especially in the case of related plants. This underground web turns a collection of trees into a complex super organism which maximises resources and allows for communication between certain species. For example, pines can transfer carbon to other pines.
These fungi mats are the largest biological entities in the world and some cover 20,000 acres. They surround and penetrate the roots of grasses, shrubs and trees. They expand the absorption zone 10-100 times and help plants in their quest for water. Their work also increases the holding capacity for the soil. Without them, disease increases, diversity of insects, birds, mammals and plants decreases, humidity falls and the now exposed soils blow away causing desertification.
The paradox of competition and cooperation
Despite playing such an important and cooperative role to so many species, trees spend their entire life in competition. They are competing with other trees and other plants for water, nutrients, light and space. And whilst they are doing this, they are also battling the cold, the heat, drought and floor, toxins, parasites and predators.
To cope with these challenges, over time they have developed more and more elaborate ways of surviving and reproducing. For example, for every one of the 750 species of fig, there is a specialist wasp to pollinate it. Evergreen trees have needle shaped leaves with a waxy layer to reduce the amount of water loss in the winter. Deciduous trees drop their leaves for the same reason.
Whilst I’ve only looked at the forest ecosystem from a trees perspective, and haven’t even covered that comprehensively, I hope you can see that a tree is not simply a tree. A tree is a complex web of relationships and interactions, and a forest is a megacity of organisms, some working together, some competing. It’s easy to think that a forest is just a group of trees but this is far from the case.