Anchor upwind and let out enough rope to reach the tree.
My best anchoring tip I learned when I was a kid. Instead of tying your anchor rope to the eye on a mushroom anchor, tie it on one of the holes in the base. Then tie the rope to the eye with a couple of wraps of mono fishing line. If the anchor hangs, a hard pull at an angle will break the mono allowing the anchor to flip over. Most of the time it will come loose when it flips.