Ever been told that when transplanting a beech tree, you should go into the woods and dig some soil from under another beech and put that into the new hole? Well, this is one old tale that has some science behind it.

Dr. Donald Marx has spent over 30 years studying tree roots as part of his job with the U.S. Forest Service. Most of that time has been spent researching a type of fungi called mycorrhiza. These organisms form a close relationship with the roots of most trees that benefits both the tree and the fungi.

Mycorrhiza grow on the fibrous feeder roots of the tree. They greatly increase the ability of the root to absorb water and nutrients. The fungus itself gets its nourishment from the tree. All common trees and woody plants have mycorrhiza on their root systems. Some have a specific species of the fungus while others play host to many different types.

Trees with a healthy population of mycorrhiza on their roots tend to grow better and are able to withstand stress such as droughts. To keep the mycorrhiza happy, the tree must be able to continually produce new feeder roots for them to grow on. Anything that helps the tree with this process will contribute to better overall health. This means avoiding compaction in the root zone of trees and being sure that water can penetrate deep into the root zone.

Work is underway to develop methods for commercial production of mycorrhiza. That way, specific trees could be inoculated with the most beneficial mycorrhiza species at planting time. Unfortunately, nobody has been able to come up with a system for keeping the fungi viable while they sit on a shelf at the local nursery store.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.



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