Hello, looking for some advice on a tree in my front yard. There are no leaves on the top and there is a green substance growing on it. I would like to save this tree if possible and welcome any advice. Three pics attached. Thank you for your time
Westmoreland County Pennsylvania
The green material is lichen. It grows when the weather has been wet and the bark is holding water. You most often see it on oak trunks.
To understand your problem, you will need to be a bit of a detective. First, scout around the branches for evidence of caterpillars or other chewing insects. Gypsy moths will eat maple leaves for example. If you see insects, catch a sample so it can be identified by Penn State Pest Clinic.
Examine the leaves for fungal or bacterial damage. Look for dead areas or areas that seem oddly discolored. If you examine them with a magnifying glass, do you see a fuzziness that indicates spores are being produced and released.
Check the trunk and branches for any evidence of borers. They usually leave a hole where they bored into the tree, and the hole may contain frass made up of wood dust and insect excretion.
Check the roots in sample areas to see if they seem healthy. Several root rots attack the tree roots if conditions are met.
You can take samples of whatever you find to your local Penn State Extension to have them sent to Penn State Diagnostic Clinic. They will report what they find and give you recommendations. If you can't find a culprit, you can call a licensed arborist. Here is a link to the International Society of Arboriculture where you can find one in your area.