Consider a densely forested area. Each tree is tall and stands alone. It’s self-contained, with its own leaves, stem, and branches. Did you realize, though, that those trees are linked by a complicated underground network? So, how does this network work? Fungi! Scientists think that practically every plant species on the planet has an interaction with soil-dwelling fungi.
These fungi can form a mycorrhizal network by connecting the roots of different trees (and the rest of the plants). The health, development, survival, and behavior of the trees connected to a mycorrhizal network can all be influenced. Trees use their network to communicate and share resources. It's for this reason that some scientists refer to it as the "internet of trees."
These fungi can form a mycorrhizal network by connecting the roots of different trees (and the rest of the plants). The health, development, survival, and behavior of the trees connected to a mycorrhizal network can all be influenced. Trees use their network to communicate and share resources. It's for this reason that some scientists refer to it as the "internet of trees."
How Does the Mycorrhizal Network Work?
Many fungi spend the majority of their time underground. Fungus grows on threads in the soil called hyphae. All of these threads come together to build a network known as a mycelium. The roots of trees and other plants can colonize and live among the mycelium. There are two ways that fungal filaments might interact with tree roots. The fungal threads cover the root and spread between cells in an ectomycorrhizal network. The fungi puncture the root and enter its cells in an endomycorrhizal network. Symbiotic relationships exist between fungi and trees, and it can be a close, long-term interaction.
Photosynthesis allows trees to manufacture nourishment in the form of glucose sugars, and the fungus and the plants share this glucose. In the meantime, the fungus collects nutrients from the earth, which it then returns to the tree. Nitrates and phosphates make up the majority of these nourishing chemicals. Mutualistic symbiosis is the name given to this type of symbiosis, because it’s beneficial to both species. However, mutualism isn't the only type of symbiosis. One species benefits while the other suffers in parasitic symbiosis.
Trees Share Resources With Each Other
Trees, too, exchange resources with one another! They transfer these nutrients through the fungal network. Tree seedlings (young plants), for instance, cannot grow as quickly in the shade of parent trees because they don’t receive enough sunlight. By sharing nutrients via fungal threads, larger trees can assist them. Trees of different kinds can also distribute nutrients. For example, various researchers have looked into the relationship between paper birches (a deciduous tree) and Douglas firs (coniferous trees).
When the birch is leafless in the fall and spring, the Douglas fir is a better nitrogen and carbon sink. However, in the summertime, when the birch trees have more foliage and have grown bigger, they produce more carbon and nitrogen. The trees with lower concentrations are transferred nutrients from the trees with greater concentrations via osmosis.
Sharing Resources Help Trees Defend Themselves
Infestations of insects and disease can swiftly spread throughout the forest, and they can be fatal to trees! When a tree is assailed, it releases chemicals that run through the fungal underground network and alert other trees to the threat. Other trees can better protect themselves if they receive an early notice. These trees' biochemistry, morphology (structure and shape), and physiology can react accordingly thanks to the warning messages.
To repel pests, a tree might alter its biochemistry by boosting repellents and toxins in its tissues. It can also potentially modify its biology by releasing substances into the atmosphere that will allure the organism's natural enemies. It’s also interesting to note that some dying trees will convey resources (phosphorus and nitrogen) to their neighboring trees before they die. This provides a boost to the healthy plants that receive the additional resources in resisting the disease.