Ice, I just reread your intentions. If I am understanding you correctly DO NOT USE A GAS PIPE AS A POST!!!! But perhaps you did not mean your gas line but a spare piece of pipe you had from a past project.
What I am seeing here is a tree species that is going to get large planted way too close to the house. It also is very thinly leafed and should not have blown over due to "sail" factor; therefore, I am suspicious of what is going on in the root system.
I would recommend some root excavation investigation. After ten years this tree should have been well-anchored in the ground. The fact that it is not is a concern. I would want to find out why it is weakly connected prior to staking or guying.
Sylvia