Welcome Scott, I'm another rock climber turned tree guy.
The two disciplines really are different but the high is the same. Sheer terror abounds when the conditions are right. Climbing DdRT is a pretty safe pursuit until you introduce saws and wood fiber under stress... falling really isn't the primary issue, it's being cut or hit by something. But falling, even a short distance is a pretty bad experience because you stop FAST... I recall that 'sore all over/been in a car wreck' feeling after about a five foot drop. It's not like a lead fall.
It's been years but we never backed up when jugging rope, it was two ascenders with etriers and daisy chains... in retrospect, tying in seems like an excellent idea.
The deal with trees is, everything is getting constant abuse. It took me a while to buy into triple action biners but after having a screw gate spin open and completely detach the other day, I'm glad I did (it was on a second TIP).
Rock climbing is great prep for tree climbing... tree climbing is technically easier but I swear I've never been so tired after climbing rock all day as I've been after standing on spikes and rigging wood for nine hours. It's a great job if you're a rock climber who's sick of working indoors all the time.