When it comes to healthy trees, most of the hard work is happening underground; it’s what produces all the things you think of when you think about healthy trees. The truth, however, is that roots are not doing all of that work alone. They’ve got a supporting cast.
Healthy soil is actually full of biological activity, including microorganisms and fungi, which support root development and overall tree health. One of the most important of these is mycorrhizal fungi, which, through a symbiotic relationship with trees and their roots, helps root systems develop and harness the nutrients and water trees need to thrive.
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If healthy roots are starting underground, then understanding soil health and the relationship between roots and soil matters. The two are intricately tied together, but one component, mycorrhizal fungi, is one of the most beneficial naturally occurring components of your soil.
Naturally occurring mycorrhizal fungi have a symbiotic relationship with tree roots. The fungi attach themselves to the tree roots, where the tree provides the fungi with sugars (produced through photosynthesis). In turn, the fungi help the tree absorb water and other nutrients from the surrounding soil. Essentially, the fungi act as an extension of the roots and improve the tree’s overall performance.
In recent years, news and research have both reported on the nature of fungal networks and how trees communicate; these two phenomena are not isolated. In fact, it’s the fungal network below the soil that builds this living network to help trees communicate and thrive.
Water, oxygen, and other nutrients may be limited, especially in areas with compacted or urban soils. Still, fungal networks spread much farther than tree roots do, helping trees access vital resources. In short, the fungal networks are vital to tree health and survival.
For newly planted trees, this relationship may be even more valuable. Even if you start with healthy stock and a dense root ball, transplantation is a shock to the tree’s system, and young trees spend their first few years focused on root establishment and development. When mycorrhizal fungi are present, young trees are better able to interact with the surrounding soil and absorb the nutrients they need to develop a strong root system.
More specifically, mycorrhizal fungi benefit trees by:
Often, the answer is yes. Mycorrhizal fungi occur naturally, so they are likely in your soil. This is especially true for established landscapes and in healthy, undisturbed soils where the networks have had time to grow and thrive.
Unfortunately, not all soils are healthy or biologically active. For example, some urban soils may lack a thriving fungal network. Largely, fungal networks and soil health are impacted by:
Essentially, this includes new housing developments, heavily trafficked areas of HOA communities, parking lot islands, medians, and new planting sites. Thankfully, soils in these areas can be amended, and adding mycorrhizal fungi can improve overall soil biology and support healthier roots, especially for new and young trees.
It’s important to note, though, that this is not a quick fix, nor will amending the soil make up for neglect. Proper tree planting, watering, mulching, and monitoring soil health are all good practices and essential for tree health and success.
If you’re wondering what’s in your soil, you can always have it tested, and your local university extension program is a great place to start (they’re often great resources):
If you’re planning a big planting and investing heavily in landscaping (especially as a homeowner), a soil test can provide insights into your soil's condition and whether trees will find it easy to thrive there or if soil amendments would be helpful.
We’ve spent a lot of time discussing how essential mycorrhizal fungi can be for newly planted trees, especially when it comes to helping them establish the root system and health they’ll need for success.
This is, again, especially true for places where the soil has been frequently disturbed or is under stress. And yes, you can add mycorrhizal fungi during planting or once a tree is in the ground.
If you’re adding during planting, be mindful that a majority of the soil around the tree should still be native soil. However, you can apply mycorrhizal fungi directly to the root ball, where it can quickly establish a connection with the young roots.
If your tree is already in the ground, you can still add amendments through:
Again, mycorrhizal fungi are not a quick fix nor the biggest driver of success for a newly transplanted or planted tree, but they are an addition that can help support healthy roots.
The good news is that the conditions we’re hoping to create not only help mycorrhizal fungi thrive, but they’re also what your trees need. Ultimately, we’re looking for balanced soils, good drainage, and soils that are left to do their own thing.
Mycorrhizal fungi (and trees) love:
If we leave with one thing, it should be the understanding that mycorrhizal fungi are an organically occurring and healthy part of soil biology, and the fungal network they create supports healthy trees and roots, including helping newly planted trees establish.
That said, these fungi are not the solution; they are part of a broader protocol to ensure healthy, thriving trees. Healthy soils matter, and starting with healthy, strong roots still matters, so where you source your trees is essential.
At SuperTrees, we’ve understood that from the start. Air pot technology helps ensure the trees we supply to landscapers, municipalities, property managers, and homeowners start with dense, fibrous root balls for a solid start. Mycorrhizal fungi can help them start growing even stronger.
If you’re looking to add mycorrhizal fungi to your landscape, homeowners can find products at our retail nursery in Riverton, Utah. Municipalities, landscapers, and property managers can work with our wholesale teams to source healthy trees and support their growth and success through our tree services, which supplement existing teams and city forestry departments.
Ready to get growing? Reach out to our team today!