Tree Felling and the Notch
Early Spring 2011

Falling trees is one of the most dangerous activities anyone can perform. With this in mind, it is necessary that every effort is made to maintain control of a falling tree and ensure safety.

Too often techniques and methods for falling trees are based on experiences or techniques you witnessed someone else use - like a co-worker, father, brother or friend. Many times the method being used is not founded on sound training or education, but rather on tradition and heritage. The problem with this is that the methods can date back to a time where the tools of the day dictated what techniques could be used.

A classic example of this is the conventional method of falling trees, where a 45 degree notch is cut into the tree being felled. This technique dates back to the days where the tools of the trade were a cross cut saw and axe. A cross cut was made into the tree and then an axe was used to cut the notch. It is curious that an axe most naturally cuts best at a 45 degree angle, and thus forms a 45 degree notch opening; hence the tradition of using a 45 degree notch has been carried forward to modern day.

One significant limitation of the conventional notch is that it only allows the hinge wood to control the falling of the tree half way to the ground (in most cases). Many times tree trunks are standing at roughly 90 degrees to the ground or terrain, which means a 45 degree arc only gets the tree halfway to lying on the ground before the hinge wood must break in order for the tree to continue falling. When the hinge breaks control is lost.

A simple way to avoid hinge failure and loss of control when falling trees is to cut a notch opening that allows the hinge to stay working and in control until the tree is on the ground. This requires a notch opening of 70 to 90 degrees. This can be easily cut with the modern day STIHL chain saw.

I do not ask you to take my word for it. Next time try opening your notch up and see if your hinge works better for you. Rather than cutting a notch that was developed with a cross cut and an axe, cut a notch that is not limited by the tools you have, but rather enhanced or improved by them.

The Following are Simple Steps to Help You Cut a More Open Faced Notch:

Step 1

Make the top cut first.

Step 2

Cut downward until the length or width of the cut is 80 percent of the diameter of the tree trunk.

Step 3

Then cut the undercut up to and even with the final position of the top cut, it is important the two cuts meet evenly and cleanly with no by-pass or mis-alignment.

Step 4

Check that the apex of the notch is clean and perpendicular to the grain of the trunk wood, this ensures optimum hinge action.

Step 5

The notch opening angle should be at least 70 degrees or more in order to maximize hinge integrity and control, a notch open more than 90 degrees is acceptable also.

This is the first of three articles. In my next article, I plan to discuss the back-cut.

by Dwayne Neustaeter
Arboriculture Canada Training & Education Ltd. www.arborcanada.com