By Tim Ard, Forest Applications Training, Inc.
One of the most unpredictable and dangerous situations confronting us in storm damage and sometimes rotted trees, is the too often presence of cracks, shatters and splits in the tree trunks, logs and limbs. There are somewhat natural windshakes, or cracks, in most standing trees but when wind, tornados, hurricane, fire or bugs start working on a tree - multiple cracks, splits or crevices tend to make planning and control an even greater concern.
Cracked, split and twisted fiber in storm broken limbs and downed trunks can be shattered and twisted into many strands. Just cutting through the log when in this condition can be challenging. Every cut releases a fiber strand that attempts to grab your saw chain and with moving weight loads tries to pinch your saw chain and guide bar.
A standing tree, that’s been fire damaged or has started the drying process at near deadwood state, sometimes creates vertical splits. Some I have seen are impossible to plan around and in these cases you are even taking a chance to make a cut unto them. The tree may collapse vertically, or twist and shatter heading in an unpredictable direction. Often times, if the tree is vertically straight, even equipment pushing or pulling is too risky. Maybe this is a good application for dynamite or a planned knock down by another tree. These killers are found often in the Western USA but you can find plenty of them in the all the states.
Winston Rall, USFS, sent me this photo of a shell of a tree from out in his part of the country. That’s a hardhat stuck in a crack in the trunk…. As I said, some trees may need dynamite.One technique option for more simple cracks or shatters may be a bore or plunge cut. They can be used to remove tension or shorten fiber length to make it possible to cut some split fiber situation. Using a bore cut slightly before or after twisted fiber may allow you to take tension out of the log or limb.
I received the following message from a Massachusetts contact:
Tim, I was in the May class in Southbridge that you taught for basic skills and storm cleanup. On June 2nd, we had an F3 touch down in Massachusetts. The skills you taught us were extremely useful in the cleanup following the storm. The hinge is truly my friend! Yesterday, I took down a 20 ft. remnant of a red oak that had been stripped of its bark. The top had been smashed off also, leaving the remainder of the trunk splintered in many pieces but still vertical. To take it down, I notched each separate splinter as if it were a separate tree, making a plunge cut for my back cut. From this plunge cut I would make my back cut for the next piece. This allowed me to fell each piece in a controlled manner exactly where I wanted it to go. Thank you for the training. I have been telling anyone that will listen what a great training program you have. Thanks again, Butch Meyer
Offset cuts can be used to remove shattered fiber. Cut the compression side first and then offset the cut on the tension side. Cut a distance just far enough to intersect the fiber you cut from the compression side, but do it a distance left or right of the compression cut to stay to the edge of shattered/split area.
Be very careful that the split, crack or shatter is not under bowed tension. They can mimic a spring pole in this scenario. When you cut, the fiber may attempt to straighten and move rapidly. Watch your position and the cutting location. Try to cut in the middle of any formed arcs.
I plan to put some of this into video form this fall along with several other techniques for applications in storm debris clean up. Until then, a great way to visualize a lot of these techniques in action is to attend one of our three-day storm debris and falling workshops. More information at www.forestapps.com
Good Sawing!
Tim Ard is president and lead instructor of Forest Applications Training, Inc. a nationwide training firm for operators in all chainsaw applications.
No comments:
Post a Comment