How Mycorrhizal Fungi Help Your Trees

What? Fungus helps your trees?

Well, not just any fungus. We’re talking about mycorrhizal fungi.

Mycorrhizal fungi are a remarkable group of microscopic organisms that have been benefiting plants for at least 500 million years. They form a symbiotic relationship with trees and other plants, becoming an extension of the feeder roots of the plant so the plants can take up more water and nutrients — by more than 100 to 1,000 times!

These fungi are living organisms. They live with the plant and provide a continued supply of nutrients for its entire lifetime – a truly sustainable plant nutrition solution.

Not surprisingly, 90% of all land plants, including your trees, employ this relationship to enhance their own root system’s capacity to deliver nutrients.

Mycorrhizae fungi threads on a plant root

Mycorrhizae fungi threads on a plant root

How Mycorrhizal Fungi Help

Trees can only take in nutrients from the soil within their rhizosphere (the area surrounding their roots). This area extends only about 1/10 of an inch from the roots.

Beyond that 1/10 inch, all the fertilizer, compost, water and whatever else you add to the soil is wasted – the tree simply isn’t able to absorb it.

That’s where mycorrhizae come in. They spread out from the tree roots in long, root-like stringy webs call hypha and bring any needed nutrients or water back to the rhizosphere for the tree. In exchange, the tree provides carbon and sugars to feed the fungi.

In effect, the fungus provides a secondary “root system” that is considerably more efficient and extensive than the tree’s own root system, allowing it to access more nutrients. One tablespoon of healthy soil can contain several miles of mycorrhizal filaments!

Healthy Soil Encourages Mycorrhizal Fungi

Soil that’s been highly compacted, treated with high concentrations of synthetic chemicals, repeatedly tilled or extensively infested with weeds will likely have few mycorrhizae. As a result, trees and other plants growing in that environment will have a difficult time getting enough nutrients to stay healthy.

Treatment with compost tea, deep root fertilization, layering compost on top of the soil and inoculation with mycorrhizal spores (yes, you can buy it!) will all help to establish a thriving colony of mycorrhizal fungi around the roots of your trees.

If you’re transplanting a tree, consider adding mycorrhizae to the planting hole.

And if you’re unsure about whether or not there are enough mycorrhizal fungi in your soil to keep your trees and plants healthy, contact us for a soil test – our comprehensive testing and analysis can pinpoint any deficiencies that are affecting your trees.


Bill Grundmann

Bill is the owner of Organic Plant Care, LLC. He takes an integrated approach to tree care, focusing not only on the trees themselves but also on the surrounding environment, managing tree health from the "ground up" - healthy soil equals healthy plants. Bill is a New Jersey Licensed Tree Expert and NJ Approved Forester with over 35 years of experience in the tree care industry.