Protecting Your Tree From Fungus

What is root crown fungus and why should I be concerned?
How do I protect my trees from fungus infections?
How to have your tree evaluated
Tips for removing ivy

What is root crown fungus and why should I be concerned about it?

Several species of parasite fungi live almost everywhere in Bay Area soils. Given the right conditions, such as consistent and excess moisture, these fungi will become active and begin to decay your tree. Unaddressed, fungus will cause long term decline and early death of your tree.

How do I protect my trees from fungus infections?

You need to be concerned when the tree's root crown (also called the root flare - the area where the trunk meets the roots) of your tree is wet, especially during warm weather. This happens when the root crown is in a consistently wet environment, such as when there is soil or plant material surrounding the base of the tree. Root crown fungus dies when it is exposed to air. By making sure the root crown is dry and exposed to air, you will prolong the life of your tree. There are three main ways to protect the root crown of your tree:

1. Remove competing plants, including ivy and lawn

These plants can hide defects such as areas of decay, and can trap moisture around the root crown, creating the perfect environment for fungus. Garbage collects under ivy and it creates a breeding ground for rats. Click here from tips on how to remove ivy. Ideally all competing plants within the dripline will be removed. Laying mulch around the trunk, but leaving the root crown exposed, can help keep ivy and other plants from returning.

A properly exposed root crown should look like the one in this photograph.

2. Remove built-up soil from around the root crown

Removing dirt until you can see the root crown may expose the fungus and will remove moisture from the area.

3. Water properly

Removing lawn inside the dripline of the tree will not only remove competing plants but will also help eliminate excess moisture. Do not water in or allow water to collect around the root flare. Do not allow sprinklers to spray on the trunk. Water away from the trunk, but still within the dripline.

How to have your tree evaluated for root crown infection:

Contact an ISA certified arborist or ASCA registered consulting arborist for an inspection. A professional, licensed and insured arborist should be consulted if the upper canopy of your tree shows signs of stress such as losing leaves, producing smaller leaves than normal or producing suckers on the trunk. An arborist should also be consulted if you see signs of decay in the wood or clusters of mushrooms growing from or next to the trunk.

Click here for a list of professional arborists.

Tips on how to remove ivy:

Don't let your tree look like this!

Once established, ivy can be difficult to remove. The method Canopy recommends is to remove as much of the ivy as you can by hand, including the roots. Ivy that is climbing up a tree should be cleared away from the trunk and separated from the roots in a 2-3 foot clearing from the ground. Pulling down the ivy higher up could damage the tree's bark. Once detached from the roots, the ivy will die and can then be removed.

Once you have removed as much ivy as possible, locate any large main root. Cut the ivy root cleanly so there is a fresh wound above the soil. Immediately paint on a 50/50 mixture of Roundup and water. The Roundup will move through the ivy's system and destroy the plant without hurting the tree or other surrounding plants.

You will most likely not kill all of the ivy in this way, and some of it will come back. Often you will have an 80% success rate the first time and 20% will return. Keep at it - in the end you will triumph.