Since thermopex is a incredibly tough outer shell, packed full of dry, closed cell foam, if a root ever found a unheard of hole or crack, it couldn't penetrate any farther inside because of the foam, and wouldn't anyway because the foam is completely dry and has no nutrients or moisture for the root to seek.
There is no better product on the market for moving heat from a boiler to your home, and it is the most tree resistant product I've seen.
After 6 years or so, I sold the house in Maine and the buyer didn't buy the boiler. I dug up the pipe and brought it with me.
Then sold it and the boiler two years later.
The thermopex was as tough as the first day I buried it.
No cracks, dents or flattening after enduring Maine winters, and two Massachusetts winters sitting in the backyard above ground.
Currently it is buried again in Barre, VT, bringing heat into an apartment building from the pellet boiler outside.
You can't go wrong with thermopex