Above the Notch

Above the Notch

By Tim Ard, Forest Applications Training, Inc.

• A storm has damaged a tree leaving a broken limb or top dangling. You can work with the situation and have a good escape plan - If nothing shakes the tree.

• A tree should have been removed a season or two ago. The top has died and is beginning to drop limbs and bark. It’s leaning in an open direction and should fall without any issues - If nothing shakes too much, especially the top.

• A tree has been badly burned during a hot fire. The top is brittle and doesn't look stabile but you have a good escape route. All should go well - If the top doesn't shake and break out during the fall.

The three scenarios above are very common but few recognize how a misunderstanding of simple notching mechanics could cause disaster.

Know the Boss

The hinge is your friend. It offers support and control of the tree, trunk or limb in your planned removal process, but the notch gives the hinge the opportunity to work. It’s the boss!

Picture the three cutting scenario’s above. Consider what could happen should the notch opening close. Whether cutting from the back or bore cutting the stem or tree, when it moves into a position where the notch opening closes, the hinge has to break or snap. Now, let’s say you have a 30 degree opening in the notch, the stem moves 30 degrees before the notch closes. If the notch opening is 30, 45, 90, 120 degrees, however wide the notch opening, it allows the hinge to work. When it closes, the hinge is broken. What happens to the end of the limb or the top of the tree when this closing and snapping are going on? It sends a whipping action and excessive shake up the stem or out the limb. If the top or end is unstable, as in the three discussed scenarios, the chance of them falling or breaking out is highly probable. Who is in control of the notch and its effects on the fall? You are, if you’re the sawyer and understand it....

It is so very important to consider the notch opening as you plan the tree’s movement. Make sure the notch opening will allow the hinge to stay attached until the limb or tree reaches the ground or is at least parallel. A straight tree with a 45 degree notch only moves half way to the ground before the hinge control is lost. An Open-Face Notch of 70 to 90 degrees allows the hinge to work all the way to the ground. It reduces chances of butt rebound, splitting, barber’s chair, pulled fiber and reduces the possibility of whipping and breaking the top back toward your planned escape route. Remember too, a Dutchman (or by-pass) at the notch corner reduces the opening to almost nothing. So make sure the notch cuts meet exact.

A sufficient and correct notch maintains minimum top shaking and movement... Above the Notch!

Tim Ard is president and lead instructor of Forest Applications Training, Inc., A training company specializing in safety and applications of the chainsaw operator.