Question
QUESTION: We purchased a home 3-4 years ago in Southeastern Wisconsin and are very pleased with a very large maple tree in our front yard. Within the past year or so the tree has steadily thinned out and looks very unhealthy. Many branches are bare and those with leaves have few. I haven't noticed anything else different with the tree. We did install a brick tree ring with hostas in it about 2 years ago, could that be affecting the maple?

ANSWER: Yes if you dug down and put the wall this more than likely cut roots form the tree and weakened the tree. Also planting the hostas and digging into the soil; around the tree trunk would also damage the roots.  About all that can be done now is water the area with about 1 inch of water per week. put a pan under the tree and turn the water on and when the pan has 1 inch of water in it stop. I would do this twice a week.  Sorry

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QUESTION: Thanks for the info. Would it help to take out the brick ring, plants, mulch, etc. or would that just cause further damage? I'm almost positive that we also put landscaping fabric in the ring as well, will that prevent the tree from absorbing the water?

Answer
At this point removing the brick, plants will do more damage than leaving them.  Landscaping fabric should not be placed underneath a trees canopy as it will inhibit the nutrient exchange essence for healthy tree and root growth. Mulching around the base of a tree out to the drip line with good organic mulch will provide weed suppression without harming the tree.
I would try to remove the landscape fabric and if the mulch is more than 3 inches thick reduce the depth.Also remove any mulch that is piled up on the tree trunk--keep the mulch depth near the trunk at about 1 inch. With the plants there removing all the fabric may not be an option but try to cut the fabric out as much as you can and then water.