Mine is a flat belt also. It's similar to the first one pictured .It can either be 3 point hitch mounted or staked down .I normally staked it and powered it with an old Oliver HG crawler of about 20 HP .
Around 1980 we took off a 5 acre woods of big hickory and small ash .Terrible waste but it was either salvage the saw logs and firewood or they would fall to the mighty D8 Cats come spring .The buzz saw worked great for the 6 to 10" ash.
We sold the hickory for I suppose axe handles .The tops were firewood plus the ash .My field looked like a log lot for a couple of years until we buzzed up the ash .There was so much of it I don't think I cut any for 4 or 5 years after that .