I had to go out and look at my model # to be sure. My flail is the heavy duty EFGC 48" with the heavy duty hammers. I chose the 48" for my use because of our woods. Plus, I can offset it so it does extend just past the right rear wheel and the belt housing on the other end is just within the wheel track on the other side. If I can get between the trees with the B2650.....this flail also fits.
In your first picture the flail would reduce that to a nice wood chip mulch without much ado but for some noise. Again, you'd just adjust your speed according to the density of all the brush and wood parts.
In your second pic, you'd want to toss aside/collect those small "logs". I've run some single short pieces that were maybe 3" diameter through the flail but it's NOISY and it may just spit a reduced chunk out the back vs. turning it into mulch.
If those larger pieces were half rotten like some of the stuff in your first pic.....that would be different. I've run some pretty solid shorter pieces through my flail and half expected to find some dents in the housing by the noise and clunks coming from underneath. No dents yet, however.
Somewhere on OTT I've got some pics of the trails and windbreaks cleaned up with the flail but I can't remember how it was titled or if the pics were added to someone else's thread. The heavy duty flail exceeded my hopes.
This is a very old farmstead and I did hit some unseen stones/metal and damaged the hammers a little. Some were straightened out with a hammer. Some I built up the edge again with the mig welder and then ground to factory shape. Those repaired hammers are still on and looking fine. There's some pics of them
here, along with why one should pay attention to belt tension.
David