By Jenna Johnson, NCCISMA Outreach Coordinator
If you are walking around in the woods and you catch yourself starting to wonder if the forest composition is changing; you aren’t alone! Many people are starting to wonder what is going on with the hardwoods since we have significant loss of ash to the emerald ash borer, American elm to Dutch elms disease and American chestnut was forced into extinction due to the chestnut blight. One of the remaining species American beech is currently under attack by Beech bark disease. It looks like white fuzz on the trunk of the tree and is commonly called “white washing”.
Photo: Beech tree whitewashed with scale, Scott Lint Michigan DNR
At first glance people think that the tiny non-native scale insect on the tree is the direct cause of death. The cause of death is actually the fungus, Neonectria. It invades through the wounds made by the insect and spreads beneath the bark, weakening and eventually killing the tree.
The two organisms work together because the scale insect’s damage makes the beech more susceptible to the fungus and the rough patches on the bark created by the fungus, gives the scale insect more crevices to settle into. Tree mortality occurs three to six years after the scale insects initially infest an area. Large trees are most susceptible and scale-infested trees with healthy crowns are a hazard due to beech snap. A condition that happens when the weight of the tree top is too heavy for the tree to hold any longer, causing the trunk to “snap” off further down.
Some beech trees are showing resistance, we know this because in an area with heavy scale there are trees that have completely clean tree trunks, meaning there is something genetically different. These trees are able to compartmentalize and block out the necrosis so it doesn’t spread.
Photo: Beech tree that has snapped due to BBD mortality
Currently there are studies being done to field test beech tree resistance to the scale, this would expedite the process. In the past one would have to wait years for the labs to process the DNA and test it against the fungus. There are things you as a recreator and landowner can do, one of these is to not move beech firewood or logs from infested areas to uninfested areas. Controlling the natural spread of BBD is not feasible because both the scale and fungus are moved by animals and the wind so once scale infests trees in your area, watch for resistant trees. Chemical control is not practical in a forest setting but in an urban setting one could hire an arborist to apply the chemicals Buprofezin or Imidacloprid to kill the scale insect.
A positive look on this tree mortality is that trees are a key component of a healthy river and an important factor in creating resilience in the ecosystem to floods, droughts and pollution. Therefore, the dead beech trees that “snap” in riparian areas are providing shelter for aquatic animals and provide nutrients and food for detritus shredding organisms with their leaves and woody material. They also improve the rivers productivity because a fallen tree can trap sediment, create pools and clean the gravel on the riverbed. The overhanging trees that have fallen in or across the river provide shade during periods of low flows and high temperature, reducing water temperatures and helping to maintain oxygen in the water.
The NCCISMA has recently launched a reward program for three specific invasive species, oriental bittersweet, Japanese knotweed, or phragmites. The reward program has certain requirements; first you must provide proof of landownership, secondly you must complete a cost-share application (can be picked up at the Mason-Lake Conservation district or e-mailed to you). Then we will provide a demonstration on how to remove the plant species, the treatments must be done according to the NCCISMA recommendations and agree to a 3-year monitoring and treatment plan. If the landowner follows all the steps listed above the NCCISMA will give them $100. If interested call 231-429-5072 or e-mail vicki.sawicki@macd.org.
For more information on the NCCISMA please visit our webpage at www.NorthCountryInvasives.org
Jenna started working as the Outreach Coordinator for North Country Cooperative Invasive Species Management Area (NCCISMA) in April of 2018. She was raised in northwest Michigan where she learned to appreciate the outdoors. She attended Grand Valley State University where she pursued a degree in Natural Resource Management, with a double minor in environmental studies and biology. She graduated in April 2015 and shortly after she got a job as the crew lead for the non-native invasive plant crew on the Huron-Manistee National Forest for two years. Afterwards she accepted an AmeriCorps position serving at the Cadillac Department of Natural Resources for ten
months. She was a forest health technician; helping private landowners and state organizations diagnose tree disease and forest pest issues throughout the state. After her service year was up she remained at the DNR as a forest health employee for 6 months. During her free time you can find her hiking with her dog, gardening or kayaking.