Is my linden dying?

[Moose74]

I have a 12 year old linden tree that until about three years ago was thriving. However over the past three years something strange is happening. The leaves are much smaller and less dense than usual, but it continues to make lots of flowers. I expected after the first year that it would just die, but it keeps going, without improving and without getting worse (at least not that I notice). Please see below three pictures, one from 2017 and three from this year. I am not sure what to do, just cut it and be done with it? Or is there hope for recovery?

 

[Raintree]

You need to check for root collar disorder. Are you using weed killers and what chemicals are you using on the patio?

 

[capetrees]

and when did the patio go in?

 

[Moose74]

and when did the patio go in?

The patio went in 7 years ago, about 5 years after the tree. I am not using any chemicals on the patio, but we have a company doing aeration/fertilization/weed control on the lawn. Not sure what product they use, they say it's "children friendly, etc...". We used fertilizer (spikes we put in according to the instructions) on all the trees in the yard, but we stopped once the linden showed signs of trouble. I will check the root collar, from what I can understand I need to dig around it to expose it. There are a lot of branches (not sure what the proper term is) coming from the ground around the trunk, I always cut those off. Ironically, while the tree looks bad, the branches coming out of the ground are strong and healthy, and develop big, green leaves, as the linden used to have.

 

[Raintree]

Stump suckering can be a sign of girdling. Checking the root collar for girdling roots or even nylon rope left untied from planting. Linden trees are sensitive to weed control treatments. Dicamba is one that can build up in the soil and cause root loss on Linden.