S.Maxson

I seem to recall seeing it in one of those "100 BASIC programs in BASIC for your BASIC computer running BASIC" books from 30+ years ago. I had an Apple ][, but I think the book was generic BASIC. I don't know if that helps you, but there might be code floating around somewhere if you're only interested in playing the game and not the specific version you remember. The only one I remember other than Norton Commander was called DOSBoss. I don't know if had the expanding trees you're describing.

Kingdom is actually the name: https://www.mobygames.com/game/kingdom