Here's the picture of the whole plant. He looks pretty healthy to me, minus the trunk... There's some sunburn on the leaves, but that's it.

To answer your question, no, not yet. Since you're watering it so little, it's delaying the time until the plant shows the effects of soil that's not porous enough. As a quick fix, you should repot that into that soil that's been cut with 50% perlite - it needs more porosity. There's been a lot written on good jade soils here (do a search for them if you want to have a more refined and possibly more improved soil than that recommended), and there are a lot out there to choose from. Unfortunately, yours isn't a good soil to have that Crassula ovata in for an extended period.

This post was edited by cactusmcharris on Tue, Oct 1, 13 at 22:40

It is not rotting. It is developing bark. That's totally normal.

Once every two weeks is not enough water in my opinion let alone too much. I water mine a few times per week without any problems. However, make sure the soil is drying out between waterings.

I just repotted him in a soil that said it was a succulent soil that was fast draining, so I dunno if that would be it. Also, once every two weeks was a rough estimate- it feels like so long in between waterings because I try my best to put it off, but it's probably more like once a week. :P
I figured it was his bark developing, bur I wanted to make sure. I've hardly been able to find anything about that stage of his development! I'm a first time jade owner and I'm super attached to Steve, so I don't want anything bad happening to him. ;_;
thank you so much for your responses, by the way!

Let me guess: Miracle Gro cactus and succulent soil?

Regardless, it's clear from the picture that your soil won't drain fast enough. Mix that soil 1:1 with perlite, pumice or turface.

Yep, I'm pretty sure that's it. Before he was in this generic potting soil that just happened to be in my garage, but after doing a little research I found that that was probably not the best soil so I just changed the soil a couple of weeks ago.
I'll look into the perlite, thanks for the advice!

When using a soil mix like you have, it is better to water too little than too much. This will help avoid root rot that you are talking about.

In regards to your picture, your Jade plant is developing its bark. This is a cool process which transforms the green stems into wood looking bark. This takes place on areas that are old enough and will continue to happen as your plant ages and more stems become old enough to transition in the process. Good luck with your Jade plant! They are wonderful plants to grow.