I don't know why my partner keeps trying to do exactly this...he digs them a big muddy pile then races over to do the tree and they run along behind him! Cracks me up to no end! He chases and swears and stomps and yells...and they just run around him to dig on the other side of the tree!
if they dig deep enough it will be fine lol but if they do it wrong well the water will be on the path again lol