When jointing two or more pieces of wood, it's important to have clean, crisp edges at the interface. This is where the trusty jointer comes in. This tool is intended to work with smaller cuts of wood and I typically reserve it for exactly what I'm doing here: matching up two pieces of wood so they glue together nicely.
Unfortunately, I ended up not being happy with one of them, so it's more poplar, planing, ripping, crosscutting, and jointing before I can engage in the big glue-up. Maybe tomorrow. Maybe.