Tall Knowledge

By Tim Ard   Forest Applications Training, Inc.

I was told a story recently of a young man assisting another to take down a tree. He was somewhere in the work area as the tree was beginning to be felled. About the time the tree was to be released he looked and saw a vehicle coming toward the target or lay area and ran out to stop the vehicle on the road. The tree fell and the young man was in its path on his way to the road. I was told he lost his life in the incident. The person relating the story said that the sad thing was that the tree wasn't tall enough to reach the road. The young man lost his life and the tree could not have hit the car coming down the road.  It was not tall enough to do so.

How important is checking the lay of the tree before beginning the cut? The surroundings in relation to the height and lean are so important. A plan must be complete with whether the tree has potential of hitting or reaching an obstacle or if a person is positioned to stop traffic, can it reach the person? How would you know? Height measure is the answer. Height measure is the technique of estimating or measuring the height of the tree before you cut.

There are several ways to check standing tree height and many different tools ranging from a stick to an elaborate laser type hypsometer.  One of the simplest, and usually readily available, is a stick or even two short sticks that can be located at just about every worksite.

The concept is called triangulation. If you can figure two sides of an equal triangle you know the length of the other side... Well I'm not sure if the terms or the geometrical theory is correct but I know the stick trick can work. Take a stick longer than your arm and measure your arm length as accurately as possible. Then turn the stick upright at 90 degrees. Sight the base of the tree at your thumb grip on the stick, then with a look upward to the upper end of the stick note what you see at the tree. If you have tree above the stick move back. If the stick is above the top, the tree would not reach your location. Right below your eye, if the visual height of the tree is covering the entire stick, on the ground will be where the tip of the tree will land. It can be very accurate.

With this technique you can estimate height for some important tall knowledge before you cut. Make sure people, pets and obstacles are well out of the way before you choose to start the saw.

Learn more at our Height Measure link on our website.

Height measure is explained in detail in our eBook (video of height measure is on our SP and C eBook versions) and the Cross-Sight info sheet. Both can be found at our eStore.