rockm
Spuds Moyogi
you can get a trunk as big as your waist if you want. All depends on how much you can physically lift/manage. You will have to lug whatever you dig back to your vehicle. Additionally you will also have to have a container to put it in. While that container will be plastic wood, etc. eventually you will probably want to get it into a proper bonsai pot. BIG bonsai pots are VERY expensive and not all that easy to find. Also you will have to lift the tree and container to perform maintenance throughout it's life. BIG pots can weigh over 50 lbs by themselves. Add in 200 lbs of soil and pot and well, hope you have good health insurance...I’m going back with a pair of muck boots and finding one with as much buttressing as possible.
How wide is a desirable base? There are hundreds of trees and some really cool/weird stuff like a double tree one large and one snaking around the larger to the point it’s become part of the main trunk.
I’d really appreciate a guide or opinions on desired sizing
By and large, BC between 6-12" at ground level have enough buttressing and character to collect. You're looking at only the first three feet of trunk. Ignore the rest of the tree--it's going to be chopped off. If there is character in the first three to four feet, it's worth collecting for the most part. SKIP THE WEIRD LOOKING TREES. Look for natural looking trunks. Weird is not all that great. It's just weird and will be weird for a very very long time. Natural looking trunks are the best bonsai.