Dying magnolia tree
I have a mature Jane magnolia tree that now has 2 seemingly dead trunks (out of 4). There are black blotches around the base of each trunk. A year ago an arborist thought it was some kind of fungus. The tree has had these spots for several years but this year 2 trunks did not leaf out. What do you think is causing this and does it mean the soil is contaminated and I should not put another magnolia there? See photos below.
Kalamazoo County Michigan
The symptoms look like a root rot issue. In recent years the Kalamazoo area has had several abnormally wet seasons. The black spots are where the fungal canker oozes sap. It is sometimes called a bleeding canker. It is possible that the tree was planted too deep to begin with, or that mulch and debris has piled up at the base. I would definitely get in there and remove all the dead wood. Secondly, I would suggest removing all of the herbaceous plants at the base of the tree (out to the drip line) to allow the area at the base to dry out and increase air flow in this area. Fungicide Treatments can be contracted by a certified arborist. Look here to find one in your area... https://www.asm-isa.org/content.aspx?page_id=22&club_id=883139&module_id=274045 Here is another one... https://ag.umass.edu/landscape/fact-sheets/phytophthora-bleeding-canker