Did not want to jump the other two tree cutting (stuck and troubled) ones but some years back we had a good one. I was cutting and a guy was running a 440 John Deere. Mixed wood but that day we were doing hardwood. He came in and started backing the skidder up so we could hook up. A small maybe 4 foot long by 6 inch stub was not cut off it came up under the 440 and pole valted or tipped it over on its side in just about a fraction of a second!!! All I could do is watch her roll he had the birds eye view. No major damage just a pain in the. Seen this happen twice in life. As most of you know skidders are light in the rear empty.