Man, I'd kill for one of those little trailers!!
It's a Metavic M95 loader on their 13RF trailer (6000# max payload). I bought it just short of a year ago from a guy a few hours down the road from me. (He bought it new in 2016.) He had what was more-or-less the Kubota version of my New Holland TC 33D CUT: similar size, weight, HP. He had it set up the trailer perfectly to work with this size tractor. To the base trailer and loader, he had added the optional 4000# hydraulic winch with 100' of cable and self-contained hydraulics powered by a small Honda GX engine. The winch makes it really handy if I'm out without my dedicated logging winch, since I don't have to position the trailer right next to every log in order to pick it up. The self contained hydraulics allow me to run it behind a pickup truck, rather than depending on tractor hydraulics.
He also added another option which is not often done on this size trailer: he was concerned about a loaded trailer pushing his compact tractor down the hills. So he had them substitute "Super Swamper" tires for the standard smooth implement tires, and added electric brakes on all four wheels. The brakes work well behind the truck. When using with his tractor he would just temporarily plug in an old brake controller and run the trailer brakes with the controller's manual control lever (since the tractor has no circuit to operate the controller automatically). I still need to wire up my tractor for a cheap brake controller - I'm trying to figure out a way to do it with something weather-proof, so I don't have to remove it when not in use.
I had wanted something like this for a while, but just could not justify the expense. When this one came up for sale used at a good price, and with only about 50 hours on it, I could not pass it up (I still can't justify it, but I knew I was unlikely to see a similar size, in good condition, and with exactly the options I wanted on it, so I jumped on it.) This trailer is kind of in a "no-man's land" for size: it's too small to be of interest for a commercial logger, yet too expensive for a typical landowner/hobbiest to consider buying new (perhaps someone with a sawmill might be interested). The next size up would probably be too big for my tractor. The next size down (at least that I could find readily available) was MUCH lighter duty, and designed for use behind an ATV, and had a manual winch or light duty electric winch for lifting the logs (Woodland Mills T-Rex, or DR Power VersaTrailer). I had considered one of these, but decided it just was not large enough to be a good match for my tractor.
The trailer is really handy for longer logs. For firewood, I could get by without it (as I did for years), since I just drop the trees, limb them, winch them to the side of the trail, and cut to stove length right there. Then I'd either load the rounds into a trailer, or split and run the output of the splitter into my trailer.