Large carvings from green wood - options?

[Dan C]

I recently took a week-long class where I got a good start on carving a mountain man bust from a piece of green butternut which was about 22"high and 13" wide. The wood has been dried for maybe 6-9 months, which means that it is still pretty green.

I haven't carved green wood like this before, or carvings this large, but the whole process really appeals to me, and I plan to continue with other carvings.

With that in mind, I'm getting my thoughts together on obtaining green wood logs for further carvings. I'm sure I can get it from tree trimmers, etc, but I need to know what types of wood to look for.

So far, my list of possible tree types are:
Butternut (white walnut)
Basswood
Catalpa
Birch
Poplar

Are there problems with my list? Are there other common tree types that I should add to my list (likely to be found in southwestern Michigan)?

I don't want to struggle with hard woods - or with pine, because of the sticky sap.

Perhaps there are tree types that will tend to split more as the wood dries and therefore should be avoided. Any advice on that would be appreciated.

Also, it may be that there are wood types that don't hold detail too well, and I would like to avoid those as well. What would these wood types be? Is willow one of these that doesn't hold detail well?

Thanks to all for any info you can provide.

Dan C.