Northern Red Oaks dying??

back40 · Sep 28, 2006

I just registered today and would like to ask about oak diseases.
I have dozens of large oak trees on my 10 acre lot (Michigan). Mostly red, some white. A few of the Red Oak (20" plus diameter) seem to be dying. Each year they make fewer and fewer leaves and the branches eventually die. It happens at a much faster rate than just aging and natural thinning. I cut one of them down a week ago (it was creating problems with the power lines) and noticed that about 30 feet up, at a major limb, there were several large "blisters" that go through the cambium, the size of a silver dollar. The bark near the blisters is pale/powdery white in appearance.

Any one who can set me straight?

xtremetrees · Sep 28, 2006

Ya got any pics friend?

treedoc1 · Sep 28, 2006

Hypoxylon canker

Identifying Characteristics

Identifying the disease:
The major signs of Hypoxylon canker are stem or branch dieback and patches of bark that fall off the tree. Wood surfaces beneath the displaced bark may be whitish-grayish in color due to the presence of the fungus and sometimes a black crust-like form of the fungus is also visible.

Susceptible trees:
All hardwoods can be affected by Hypoxylon canker but species of oak are most highly susceptible. The fungus is more likely to infest oaks that have root system injuries or diseases or have been weakened or stressed by such factors as drought, poor nutrition, soil compaction, or construction damage.

Mostly occurs further south but I am seeing more and more the past few years.

http://www.forestryimages.org/browse/subimages.cfm?SUB=564

paste this site in for a variety of photos

back40 · Sep 29, 2006

I'll work on getting pictures this weekend.
It does not look like the fungus in the pic's. The blisters look like someone shot the tree with buck shot; several distinct "holes" in somewhat of a pattern, much too large for a woodpecker/sapsucker. The white/light color I mentioned is on the surface of the smooth bark, as though flour were dusted on it.

tprosser · Sep 29, 2006

Two lined chestnut borer

It could be two lined chestnut borer. These insects attack trees under stress and will kill them over a period of 1 -3 years. Usually the dead leaves will stick to the tree. The die back usually starts in the 2nd half of the summer. Michigan had a serious drought a couple years ago and this may be what weakened the trees. Soil compaction can also slowly weaken an oak. These can be treated if not too far gone, but require that the cause of stress be addressed so the trees can rebuild their energy and bolster their own defenses.

Hope this is helpful

back40 · Oct 4, 2006

The two lined chestnut borer is the most probable cause. Thank you, tprosser. About two years ago, my wife planted a perenial bed all around and near several of the affected trees. She made a clay base with topsoil and compost covering.