Question
Mountain Ash issues
Hi,
We have a American Mountain Ash tree that all of a sudden has something growing on it. We don't know if it is a scale of any kind or a problem starting with the tree. Also, in one of the pictures you'll see a dark brown spot that is part of the bark peeling out. It's the only spot like that but I was able to chip off some dead bark there that was rotten. There is also a Magnolia tree close to the Mountain Ash that developed Magnolia scale last year. We had it sprayed a couple of times but I don't know if this would have anything to do with the issue this spring on our Mountain Ash. Hope you can help out.
Thank you.
AnswerThese are lichens.
Lichens are an example of a symbiotic relationship between algae and certain fungi. They are capable of producing their own food. The algae associated with the fungus is a green or blue-green alga. There are three forms of lichens based on growth patterns. Crustose are species that are closely pressed against the surface of the limb or trunk of dead or live trees. Foliose forms are leaf like or prostrate but are also tightly attached to the tree. Fruticose forms are bush like, erect or hanging. Although lichens are found in most areas of Texas, they are most noticeable in areas that have extended periods of high humidity.
The effect of lichens on a tree are only slightly detrimental. The plants are epiphytes. That is they derive their nutrients from the air and not from the plant on which they are growing. Although they are not parasitized, literature reports suggest that lichens do have a slight negative effect. The main concern is that lichens give a tree an unkept appearance. Presence of lichens also is a good indicator of a thin tree canopy. This often leads homeowners to conclude that lichens are the cause and not the effect of thin foliage. The best control for lichens is maintain the tree in good condition. This will insure a dense canopy which will shade the limbs and reduce photosynthesis. Without photosynthesis, lichens are not able to manufacture food needed for growth and development.
The baking soda recommendation I have heard of is 40 pounds of baking soda per 100 gallons which comes to 0.4 lb of baking soda to 1 gal of water. But I would not do anything about the lichens but I would fertilize the tree with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. this will increase the overall health of the tree.
There may be a fruiting body from decay fungi growing from the rotting place. These decay fungi live on woody cells and over time will cause a tree to become hollow. They will not effect the overall health of the tree. and since they are inside the tree there is really nothing that can be done short of keeping the tree healthy.
The scales on the magnolia had nothing to do with the lichens or the decay fungi.
