TO anyone who can help,

I was directed to your class through a soils course I am taking. My family has an approximately 50 year old silver poplar in our yard in South Dakota that is a perfect shade tree and has been part of our home for decades. However, in recent years the roots have been breaking through through the soil. (I believe they call them knees) They look much like a bubble up root mass, and needless to say they are break up our lawn. It has only been happening for the last five or so years. I believe it because we have been watering the grass more and the water table is higher in the area. But what our your thoughts on stopping these "knees."
Thank you,
Shane

That is a possibility,but also it could be that you might have sandy soil preventing the roots from going deeper into the ground. And old tree roots usually come up from the ground after some time anyway, probably because the diameter of the roots grows bigger in time.I myself would just let nature take it's course, and enjoy what you see, for you could possibly have no trees, and enjoy no shade at all!