A guy I know who runs a bulldozer and clears a lot of timber mentioned to me that mills will not take saw logs that are cut out of trees that have been pushed over by a dozer. He thought it was due to something about stress introduced into the log due to being pushed from a point high up on the tree. Does anyone have any experience with this?
(Sawing and Drying Forum)
From Gene Wengert, forum technical advisor:
I have never heard that and I cannot image, from a scientific point of view, what that is all about. I can imagine that some bulldozed logs might have more sand or grit, but that relates more to the operator than the equipment.
We have sawn hundreds of cedar logs from trees that were pushed over. We just made sure there were no stones in the area where the blade hit. I wouldn't pay full price for these logs though since you have more prep work on them.
One of the most important tips I can give you is to slow down your normal cutting speed in the wood. This has prevented me from getting hurt several times because a tree with lots of stress will often release it by splitting up the tree as with a barber chair when felling a leaner improperly. If you cut slow the portion released will often be smaller than if you're cutting fast. A split like that often has a delay to it so by cutting through the wood slower it will release the hidden stress in smaller degrees of energy, like a fault line that has a lot of small quakes instead of building up all that energy and letting go in one violent event.
Always be conscious of what the tree is telling you don't let your mind wander about how pretty that wood will be and working with it in the shop. You can actually feel stress release even through a running saw especially compression on the blade of course. If your sixth sense has your attention, shut the saw off and listen to the tree. I'm sure you've heard those warning pops some loud some not so loud - you'll hear a lot of them when removing from a pile. Take several wedges, a sledge, and an extra saw. If you get a blade pinched severely and can't open the kerf with wedges and don't have a safe position from which to cut it out, remove the power head and retrieve the blade later after you cut enough trees away from it to remove the stress. Don't fixate on getting the blade out to the point of getting swatted with several thousand pounds psi in the kisser.
Avoid standing on the tree you're cutting no matter how stable you think it is. It抯 best not to stand on a tree at all because once stress releases the dynamics of that portion of pile can change dramatically and you can get thrown, rolled on, or swatted by another tree you didn't suspect was pinned by the one you're cutting.
I'm not trying to come off as a know-it-all. I have the scars and broken equipment to testify to the mistakes I have made and continue to make. I do have enough experience doing it to know it is a whole different ball of wax than what you might expect, and since you've never done it I thought it might be a good idea to warn you. Have your thinking cap on under your helmet. Make sure you have someone with you - never cut from a pile like that alone especially without prior experience doing it.
I don't want it to seem like I'm dramatizing the danger, because it really is a dangerous thing to do even for loggers with years of experience doing it. Good luck. One final thought: Never underestimate the potential energy in "a little 'ol bitty limb". The trunk is not the only danger to you; a small limb can have enough stored energy to give you a compound fracture or take your head off!