What is Beech Bark Disease?
Trees become infected with the Beech Bark fungus (Neonectria species) where scale insect populations explode. The trees experience infection after the beech scale insect (Cryptococcus fagisuga) feeds. After the initial feeding, you may then notice infection of the fungus, which establishes itself by entering tiny wounds made by the feeding insect. These insects are capable of moving 6 miles per season via wind, birds and people posing risks to neighboring forests.
You will first notice the presence of a scale infestation by protective, wooly tufts on the bark of the tree which is secreted by the scale insect itself (figure 1). Later infection, usually after 2-3 years, expresses itself by forming pocks, cankers and small yellowing leaves with general sparseness in the crown (figure 3).
Using Infected Wood for Mushroom Production
These trees will often snap at the location of a large canker, a dangerous situation in areas that may have high use by people and animals. For mushroom growers who are aware of Beech Bark disease, you can salvage some of the wood to use for mushroom logs. Several citizen researchers have documented through trials that the wood, especially from bolts or logs only lightly infected in the early stages, can be productive for Shiitake mushrooms. A trial in 2022 conducted by Kent and Lyn Black, showed that at least for Shiitake, infected wood was suitable to use. We have yet to obtain information on the use on other mushroom species such as Lion's Mane.
Another case study comes to us from citizen researcher Judith Heintz. Judith Heintz manages the Heintz wood lot near Lake Placid, NY, and got involved in the project after a friend encouraged her to attend a workshop presented by researcher Dr. Ken Mudge from Cornell University.
As Judith put it "I had no intention of pursuing the raising of mushrooms, but my friend said "you have all those beech trees that are dying. You harvest the young ones before they get the disease. I would like to help you do that." And that set in motion the 7-year adventure in mushroom farming on a very small basis for personal consumption only."
Judith started harvesting Beech trees for mushroom wood in 2017. She started by using only small, mostly disease-free wood, but by 2023 all the wood she harvested from her lot showed signs of the disease. Overall she harvested 1,945 mushrooms from 37 logs in 5 years with 2 harvests per year, and is still planning on continuing to harvest as the logs produce.
In Conclusion: Try to use beech logs from mildly infected trees. You can use logs with more advanced cankering, but yield will likely decline the more heavily infected the logs are at time of harvest.
Managing Your Woodlot to Protect Beech Trees
Control of the disease in the forest setting is difficult but there are some things a woodland owner can do if working in tandem with a forester. Your forester may suggest to removal of some infected trees near the healthy tree and remove all suckers within 5 feet of the healthy tree. Keep in mind that stocking as many healthy Beech trees as possible is important for forest and wildlife health. Homeowners with large beech trees on their property should monitor them for patches of dead bark caused by Beech Bark Disease, which makes the trees vulnerable to breakage. If trees have dead tissues, they become hazardous to people and property and should be removed.
