Читать книгу Chainsaw Manual for Homeowners - Brian J. Ruth - Страница 17

Because of gravity, heavy stuff—like trees and tree limbs—tends to fall down. A leaning tree tends to fall in the direction of the lean, and a log lying on a slope tends to roll downhill. Common sense informs you and guides you to be out of the tree’s path.

The energy in living wood is another thing. Wood is supple, and it will bend a long way before it breaks. A limb that is bent under the weight of a fallen tree may pack a tremendous amount of force. The chainsaw operator must learn how to read these forces to predict the behavior of a sprung limb when it’s suddenly cut free. There are three different situations to look out for:

■ Free limb. When you cut into the limb, is it free to fall? Will the falling limb close up on the chainsaw bar, trapping it in the wood? Or will the sawn limb fall easily away? Where will you be—underneath the falling limb, or safely out of the way?

■ Sprung limb. Is the limb trapped and bent (sprung) between the weight of the tree trunk and the ground? When you cut into the limb, is it liable to recoil violently? Which way will it go? Where will you be—in the path of the flying wood, or safely on the other side of the tree trunk?

■ When you remove a limb from a downed tree, what’s left to hold the heavy trunk up off the ground? Is it going to drop straight down, or is it going to pivot unpredictably on the remaining limbs? Where will you be—in the path of the dropping or rolling wood, or safely out of the way?