Here is what is left of the original greenhouse - a little more than one-third the size. The structure was likely older than I thought by the look of the rotting wood around the base. And luckily, the rebar used to anchor it in the ground was not cemented which made the demolition that much easier.
I'm still not sure what I'm doing with the portion that is still standing but the majority of the demo work is done ... I can now start focusing on the new greenhouse and shed to replace what I used to have here.
Here are some photos of the demo. Lots of heavy work!