Question
My wife and I are planning to plant a Hawthorn tree and would like to know if it is a center tapped root tree.  Because we would like to plant it close to our new patio and we don't want to have a tree with a root system that might spread into the patio.

Answer
The root system is more fibrous but will not cause any problems with the patio. The spread of the tree maybe 25-35 feet at maturity so the branches maybe a problem if planted too close to the patio.
There are many varieties of hawthorn trees and some are dwarf and are not as large as the "regular" ones. I would check with your local nursery and ask them for a variety that will fit your area that you plant to plant. But the roots will not be a problem.