Actually statistics say most treestand accidents happen either climbing up or climbing down. And for the vests HSS, Muddy Outdoors, Spider Safety harness. All great harnesses.

Everyone should read that link in the post by Valentine. I knew there were some problems that could develop if you hung in a harness, but I had no idea you could pass out and croak in a short period of time.

Muddy harness for me. Nice and light, comfortable and easy to put on in the dark.

I used to do a lot of rock climbing in my younger days. Most fellows would be well advised to learn how to use a Prusik knot (hitch). With a couple of short pieces of cord, even shoelaces in an emergency, a fellow can tie this hitch and climb up. There are a couple of improved versions but the concept is the same. The hitch slides on the rope until weight is applied, then it grips tightly.

http://www.chockstone.org/TechTips/Prusik.htm