I have a couple who came into the Clare County MSU Extension office trying to save their trees. Do you have any insight or into what might be causing them to decay. If so any ideas on how to try and save them. They tell me they are a Emerald Green Arborvitae. I have attached a picture of the trees as well as a pic of the dead foliage found below them.
This appears to be deer feeding damage, leaving behind just the brown needles beneath the green. Arborvitaes are one of their favorites. If these trees were not well watered during dry times last season and just before the ground froze, much of the browning will be from lack of hydration. Here are articles describing what can be done-
If deer have been excluded they have a couple options: monitor the plants and if needles continue to die or turn color or appear to be eaten or distorted, get pictures and have samples with needles diagnosed.
To confirm that there is disease they can submit samples to MSU Diagnostic lab, along with pictures; or hire a certified arborist to come on site and give a complete diagnosis. The MSU website has the submittal form, instructions on how to correctly take samples, and the fee schedule: https://pestid.msu.edu
There are several certified arborists in Clare County. To find a certified arborist search here by zip code: www.treesaregood.org
Having an arborist come on site can also confirm that the trees were planted correctly. Correctly planting trees is critical to their long term health. The arborist will also give a complete care plan, including water, fertilizer, pest treatments, and pruning advice. If the branches were not damaged completely, it will take 3-4 seasons before they grow back, and then only if the deer or disease issue is handled now. They should see green sprouting some time this season.
If you have more questions, please write again. Thank you.