A forest of young American beech, Fagus grandifolia, withering under the attack of an as-yet unknown plant disease. Lake County, Ohio.
Just over two years ago, I wrote about a mysterious affliction that was decimating American beech trees in parts of northeastern Ohio. You can read that post RIGHT HERE. It was brought to my attention by John Pogacnik, biologist with Lake County Metroparks.
Last week, John reported with an update, and the news is not good. Experts remain stymied as to the cause of the affliction, which seems to be spreading. All of the photos, and much of the text (lightly edited) that follows, is from John. Read on, and then see recent photos of affected trees following the text. All photos, I believe, were taken recently in Lake County, Ohio.
"Basically experts have been looking at it for three years now and cannot nail down a cause. They have studied the roots, leaves, buds, and branches, but cannot find anything. They see problems, but they appear to be there because the trees are dying or stressed and are not the cause. Holden Arboretum has a project where they are carefully studying affected trees to document how the disease is spreading. The Ohio Division of Forestry and US Forest Service will use this information and what I have compiled to apply for a grant to hire a grad student to study it full time. I think that may be the way to go.
We have parks like Hell Hollow where 100% of the beech are
affected. I am seeing some prime breeding bird habitat changing
drastically. What once were dense shady stands of beech and hemlock are
now becoming open and sunny. I am seeing a decline in some of the hemlock
nesting species already. Hell Hollow has thousands of beech and I cannot
find any that are not affected. To give you an idea on how fast it
spreads, at Chapin Forest I found three affected trees in 2014. In 2015
about 25% of the trees showed signs of the disease. This year at least
70% of the trees are affected and some are really looking bad.
It appears that the disease shows up first as a few striped
leaves. It might be just on the tip of a single branch. My guess is
that in the winter it goes down into the roots and the following year all the
trees in the clone are affected. In smaller trees later stages of the
disease will have only a few leaves that are at the tips of the branches and
these leaves are curled up and contorted. There are typically unopened
buds on the branches. The trees typically do not drop the leaves until
fall or winter. The leaves come out of the buds all contorted. They
look dead upon opening in May. The leaves and trees do not get worse
later in the year. Large trees appear to be dying from the bottom up.
It appears it originated from somewhere in the south end of
the central part of Lake County. Spread has been very rapid to the east
and slowly to the west. This tells me it is probably wind driven.
What scares me is unlike with the ash borer that leaves some trees untouched,
this affects every tree.
Things to look at identifying the disease are the striped
leaves. They are best seen looking up into the crown. Anthracnose
can look somewhat similar, but lacks the striping. The leaves also remain
on the branches through summer. They do not drop and get replaced by new
leaves as in anthracnose.
I’ve attached shots showing the upper and lower surfaces of
the striped leaves, latter stages of the disease, and what some of the affected
areas look like.
Unfortunately for us, this is just the tip of the
iceberg. We also have emerald ash borer going through. We also have
something killing sassafras. This might be from an Asian ambrosia
beetle. We have elongate hemlock scale at Chapin Forest and Penitentiary
Glen that will end up killing hemlocks. This is the first “wild”
occurrence in Ohio.
I am also seeing large areas of dying trees that may be a
result of Armillaria fungus. At Penitentiary Glen there is an area almost
5 acres in size that is spreading outward. These areas are kind of
interesting though. They occur in wet areas where there are seeps.
The open sunlight and rich soil increases plant growth causing a lush growth of
grasses, sedges, and forbs. The open light attracts things like red
damsels, spiketails, and wetland butterflies. Some of the oaks that are
dying are 100-150 years ago. There some amazing ecological changes going
on here. I think the extremes in weather due to climate change are stressing
out the trees making them more susceptible. Add to that the earthworms
which are rapidly also getting worse and you have a an ecological disaster."
Affected newly emerged leaves
Heavily affected leaves
Underside of leaf
Upperside of leaf
Heavily affected young American beech grove