Many Sugar Maple trees have black trunks and scaffold limbs. However, the normal color of Sugar Maple bark is a light grey which makes the black very visible. So what causes the bark to become black and is it a danger to the tree?
When closely examined, this black coloration often appears to be much like wood soot. There is a depth or structure to it which does not look like paint. This structure is a hyphal mass and is composed of dark colored mycelium and spores from a fungus. This fungus is not a disease of the tree but it feeds off sugars from the tree. The “sooty” appearance of the fungus on the bark gives this condition its name: Sooty Mold. These sugars are found in the sap of the tree which leaks out through some sort of damage to the bark.
How Did My Sugar Maple Get Sooty Mold?
When a tree is damaged from a storm breaking a limb, a pruning cut to remove a limb, or from injury caused by an animal, the sap will naturally leak out through that damage. This is a natural, normal defensive reaction of the tree. This sap then begins to flow down the tree, soaking into the bark leaving the sugars in the sap behind. The fungus then feeds on this sugar and grows causing the black color on the bark.
One of the primary causes for damage to Sugar Maple which leads to Sooty Mold is the activity of Sapsuckers. These are a group of small woodpecker birds which “drill” rows of holes into the bark causing the sap flow on which Sooty Mold feeds.
Sooty Mold on Sugar Maple trees is not a disease and under most situations will not cause any harm to the tree. Sooty Mold is more an aesthetic issue than a health issue for the tree. Unfortunately, there is no cure or preventative measure but rest assured this is not a sign of bad health in your tree.
How do you get rid of the black mold growing on the maple bark?
I have used both pesticides and fungicides but wit no success!
Would washing the trunk with detergents help??
I am responding to your request about the black sooty mold on your tree. The mold grows on sap which leaks from the tree. The sap leaks out from some sort of injury, either a broken limb or more commonly from Sap Sucker damage. Sap Suckers are small woodpeckers which drill small holes in even rows along the trunk of the tree. These small holes will then leak sap from the tree which the bird then eats. As the sap leaks out it spreads down the tree, this sap is high in sugar content and the mold then grows on the sap causing the bark to turn black. There is no cure, no recommended treatment, for this condition since it is not a disease and does not cause any harm to the tree. I do not recommend trying to wash the trunk as that may cause harm to the tree.
Please contact me if you have any questions.
My sugar maples are dieing one at a time from the black stuff all over the cut down one last year and now another needs it two more are turning black I live in Arkansas
HI Lois, Is that still happening? Have you found out what it is? I have something doing that to mine, too. They are losing their bark. But they have the sap sucker holes referenced above for sooty mold. Wondering if you have figured out what is going on with your trees?
HI Lois, Is that still happening? Have you found out what it is? I have something doing that to mine, too. They are losing their bark. But they have the sap sucker holes referenced above for sooty mold. Wondering if you have figured out what is going on with your trees?
Why would you use pesticides on a mold? Pesticides are made for insects not plants. Herbicides are for plants but are made for specific plant types, you have to READ the packaging, don’t assume just because it kills or damages one thing, it’ll do the same to another. Use an alcohol deluded spray on it if it’s so bothersome
Pesticides are not just for insects. Pesticide is umbrella term that encompasses all things made to eliminate pests. The most common of these being insecticides, fungicides, herbicides, and rodenticides. Less commonly known examples are nematocides, miticides, and molluscicides.
Hello, I read your response to the other gentlemen whose sugar maple tree looks much like mine. There are definitely many holes that look like what you described from sapsuckers on my very old mature sugar maple which looks quite healthy other than the black discoloration around the lower trunk. I was told by an inspector from a different company than yours that this was from verticillium wilt and it should be treated with a spraying of phosfonate once per year to control it. I’ve read other websites about this and some describe exactly what you have described in your answer. Others talk about a variety of other fungi but always in unhealthy declining trees. Mine is quite healthy other than the black trunk bark. I’d appreciate your opinion on the above. Unfortunately I’m in N Y state so I can’t invite you to inspect or work on my trees. Thank you so much for your help.
Verticillium is a vascular fungal disease which manifests itself in sudden limb dieback and eventual tree death. It moves in the soil and infects the tree through the root system. Black trunk staining is not a sign of Verticillium. As the article stated, the black staining on maples is most commonly caused by sap flow promoting Sooty Mold development. Occasionally scale insects and aphids will cause similar Sooty Mold development, these insect pests can be controlled with properly timed and applied pesticides.
Hi. My maple tree trunk divides about ten feet up into large “trunks.”. The bark on one of the upper trunks and that side of the lower trunk have turned black and several of the large limbs (4” diameter plus) from the black upper trunk broke during the winter. They look splintered and very dead. So that side of the tree appears to be dying. Is there a way to save the healthy half of the tree, or is it necessary to take down the entire tree since one side of the main trunk is black?
I’m having the exact same issue. One half of my tree is totally dead and one half alive. It also has the black sooty fungus only on the dead side. It didn’t leaf out this year on that side. Some leafed out in the section in between the two sections but has now died. I’m sad cuz it was a beautiful shade tree for the house. But the living side is too far from house to help. Going to take it all down.
Unfortunately, my maple tree is suffering from the Sooty Fungus.
Now that all the leaves have fallen,
The entire tree is covered in black fungus. I noticed that young limbs are snapped off as well at the top of the tree. Looks like it’s dying. I also have several stress marks going up the tree. Splits in the bark.
The tree is is 17 years old. I don’t know what to do as far as treatment vs taking the tree down. Can it be saved? I recently cut out mistletoe that attached to a lower branch.
I have an old maple and in the past five years the trunk has become progressively black. It has as described, rows of woodpecker holes. I just had an arborist tell me he would inject a fungicide at a ridiculous rate, $3,700 to cure our tree. However, after reading your description, the actual tree may be fine?
So folks, the sooty mold and black bark are results of sapsuckers, they do not kill the tree, but their beaks might have carried some fungal or bacterial pathogen that aids in the trees death. No stopping the birds, but some of the diseases can be stopped, or limited in their actions by a good arborist. If the tree is dying in part from the center and top, it might be Phytopthorra root rot. Maples also often get Nectria canker that can kill them one branch at a time.