Do these trees have a disease?

Asked March 25, 2020, 3:14 PM EDT

We have several pine trees that have begun to look sparse and thin. It appears as though something may be spreading between them. Are they ok to remain or should they be taken down?

Jackson County Michigan

1 Response

Are the yellowing thin trees a type of fir? It looks like a rotation of fir and spruce, and the fir are the ones not doing well. Fraser fir, which is commonly grown as a Christmas tree is more difficult to grow than spruce. It does not do well in hot dry conditions in summer and where it grows naturally it has moist conditions. Douglas-fir which is not a true fir does have problems with a fungal disease. I would need to see the needles under a magnifying glass to know if it is diseased. The way to tell a true fir, like Fraser fir from Douglas-fir or even from a spruce is that true firs have cones at the top of the tree that grow upwards, while the spruce and Douglas-fir have cones that hang down. Firs also have needles that spread out on the twigs laterally in a plane, while spruce have pointy needles that go around the twig. If these are Fraser fir or a closely related species of fir they require watering during hot dry conditions. You could send samples to the MSU Diagnostic lab on campus to have them check for disease. The Diagnostic Services information can be found on their web site at: https://www.canr.msu.edu/pestid/