stress cracks in structure

[north country dozer]

Thanks again guys... My pins are loose on my front end but that's what you vet with an 81 dozer that most likely has original pins. Recently logged 4 white pines for siding lumber. All ranged between 24 and 28 inches for about 30' up. Have a lead on some loving for a neighbor so just wanted to be sure about pulling with the blade. Probably gonna weld hooks on the blade for this one as its quite a bit more than 4 trees . Thanks again guys