Recently we had an opportunity to try out a forestry mulcher with our 4R.
Here is how it went:
As it was only a trail run we did not get much work done. We wanted to see whether we could have use for such attachment and whether 4R was worthy of it.
It is definitely very taxing attachement. If you go just a bit faster than you should engine load goes to 100% immediately (tractorplus app) and it can even bog down a bit.
Because of miscommunication with the seller this mulcher had 1000rpm gearbox so with proper gearbox I believe it would work a lot better with less bogging down.
Weight of the implement is another major challenge. We could not use this one with the push frame because it was already too heavy and would not lift. Them JDs with their great power but measly hydraulics. If we decide to buy this exact model I would definitely have to increase the hyd. pressure.