Agree with Hort. At this point the biggest problem is all those small roots above the root flare. Get rid of them by whatever means is required. Also since you tree has been planted for a year, the lose of these small roots probable won't significantly affect your tree. I personally would remove the extra soil, as even if you cut all the adventitious roots above the flare, they will tend to grow back if the excess soil remains there, very possible presenting the same problem at a later time. I assume this was a balled and burlaped tree? If however was a container tree, then I'm concerned above more girdling roots further down. Arktrees

That died due to girdling roots. One cause of which is planted too deep. another is was in container too long.

I did my red maple in earlier in spring, trying to raise it. Mine was planted about 10-12" too deep, but I planted it myself, with the help of a hired hand in fall of 2015. BTW, I'm in Marlboro NJ, zone 7A. The tree in question was a beautiful October Glory maple. I was just aiming to get the top of the burlap bag an inch or 2 above the surrounding soil, not realizing until next spring, that I had made a mistake. It started out a beautiful 'rubrum' in spring, giving me hours of pleasure, as I just stood around it, sometimes nursing a drink. But as a very wet spring progressed, and the leaves were still not opening out fully, my mind raced to a number of things that could have gone wrong in the planting. I definitely had not cut the cage around it as thoroughly as I should have (damn thick guage wire, so hard to cut with pliers!). So, one very wet day, in a very very wet week, I started investigating, prying the dirt away, in an effort to find the wire cage. In the process I discovered that I could not see the root flare at all, instead the trunk was buried, and was discoloring and fraying from the surrounding soil and water. So I decided to raise it. I leaned on the tree, this way and that until it was moving on it's root ball. I shoveled dirt under the root ball, trying to work it in with my foot. Then I had a brainwave! I soaked the root ball and surrounding with water and waited. As the water drained down, the dirt mixed in the water found it's way to the bottom, while I was still wiggling it. It worked, the tree was slowly raised. And then I made the fatal mistake! I also saw roots that were growing from down on up. Now, with the tree raised, these roots were poking into the air. I started cutting them, some of them were big and juicy. I felt horrible, but could not stop! After I had raised and root pruned the tree to my aesthetic satisfaction, I covered it with dirt just so, and mulched and staked it. It looked really nice, with the frayed trunk, previously suffering the indignity of being buried, now finally breathing and recovering, or so I thought. I kept the tree well watered, even spritzing it a few times a day (deputizing my kids in the job as well). But the leaves started drooping. I increased the watering and spritzing, but to no avail. One by one, the leaves gradually turned brown, and then dropped. After a few weeks, in a frantic effort to save the tree, I cut back the branches a couple of inches from the terminal buds to encourage growth. But to no avail. Right now, it's late August, and a scratch test reveals a dead tree. No cambium, no phloem, no nothing! There are leaves growing from the base, but even those are drying up right now. So, I will definitely be replacing the tree. I have a question from this learned group, but I will first let this greek tragedy soak in first.

Joshua, I'd like to answer your question directly: yes, trees can die suddenly. They can also die very soon after being planted too deeply. I'd have to say that it is the number one reason for decline and death in trees, at least in my career. Some years ago, I was called out to the large property of a high end retail complex, not a mall. The tree and landscaping installations were extensive, even extraordinary. I was called by the CEO to inspect the site about two months after completion of the job. The majority of the large trees were in serious trouble....after two months! The plants had all been planted anywhere from 6 to 8 inches below grade into a soil that stayed too mucky, too wet....especially at that depth. Tree roots must have oxygen at that shallow root zone...or they can die. Most of us know that the essential absorbing roots of trees are shallow. Planting too deeply impedes the development of new roots. So, the decline process can begin immediately and end swiftly......or a tree can languish for years before finally croaking. Trees that have been installed that deeply have been planted improperly, plain and simple.