Syzygium australis tree root across pathway, is it possible to shave down 2 inches for approx 3 feet (the width of the path) along the root and seal it with something to avoid stressing the tree. I am in a sub tropical climate and the root is thick oval shaped and goes deep about 12 inches deep and I would be shaving down from about 8 inches from the main trunk.The tree is 30 years old. I want to lay a paver stone path and dont know if I can successfully shave the top off the root or should I just build up the gravel level higher than the root to lay my path on.
It's possible, but not advisable. For one thing, using a sealant of any sort on any woody part of a tree is no longer recommended, since infection rates proved to be higher in trees treated this way. Removing a root entirely is worse than shaving some off one, but both may compromise the tree by putting it at risk of either instability or infection.
The best option is to raise the gravel level higher rather than interfere with the roots, but should you decide to risk root shaving, there is guidance here https://www.gardeningknowhow.com/ornamental/trees/tgen/shaving-down-tree-roots.htm