Conduit is a short term solution. It will not be strong enough for a mature tree that requires staking. Aluminum window screen 24" wide, wrap it around the base of the trunk and staple the edges together with a regular paper stapler. The tree will pop the staples as it grows.

Conduit for most of my temporary plant staking. To avoid disturbing the plant when it is removed you need to insert the stake at an angle. Come out about 1' or more from the tree and drive the stake at an angle toward tree to attach. For a few months staking I reverse electrical tape and secure tightly. If the plant needs a year or more leave a little space when taping. Works great for most of my trees in there time of need.

In the early years of my fruit experience, I used hardware cloth to circle the trees--got stabbed so many times !

Then I tried aluminum window screening, and it works. It's also cheap and easy to form to the shape you need. It seems to work against voles and other critters.

I though this was my exclusive find--but TurCre beat me in revealing this tip.

I found electrical house wire works good to hold the tree to the stake. I drive my stakes a foot away and reach out with the wire and make one bend around the tree a little loose.