Rot and Fire Damaged

By Tim Ard, Forest Applications Training, Inc.


I had a great question come in this week regarding the difference between working on a green healthy tree and one that many sawyers have to deal with -- dead, rotted or fire damaged trees. Some may be standing, others may be hung in another tree or just  lying there to clean up after falling to the ground. This is an awesome question, but a tough one to write about and illustrate in words. During hands on training I can go over many situations or at least address them with a similar tree in front of the class. Without having you in front of a tree to show and discuss it's hard to justly describe and write about a technique and even harder for one to see with the minds eye. I will attempt to cover some of the more explainable things however...


Let me say this first to reemphasize my ever-important stand on the use of the hinge in felling and bucking. You must understand how a hinge should be considered or established in these discussed operations to see their effectiveness and safety. Sounds complicated? It is, unless you can first define it - The hinge is a predetermined section of wood, that connects the stump to the falling trunk stem or a log or limb section to another. Predetermined means you have a clear thought in your mind as to how much hinge you want to leave attaching the two parts.  You just don't simply cut, you plan it.

 Hinge Percentage of Diameter

The hinge dimension (rule of thumb) is approximately 10% of the diameter in width and 80% of the diameter in length. The diameter is a measured cross section of the tree or wood/log section. This calculation gives you a very predictable place to start in establishing a successful controlling hinge.


Now to our issue's of burned or rotted trees.


The planning process remains the same as with every tree to cut- establish the five steps - 1. hazards, 2. leans, 3. escape, 4. hinge dimensions and 5. how to cut, selecting tools and kerfs (back to front or bore cut).


I wish I could explain everything regarding what to look for in hazards and leans assessment but it is probably best left for a class or video and still you would not completely cover all the possibilities. Listing out all the possibilities may overwhelm some people. I still find sawyers, including myself, that forget important things sometimes to watch and plan for....


To identify just a few of these obstacle and hazard considerations --


Regarding initial techniques used to cut the tree or log; after your plan is established, burned or rotted fiber is usually found in the tree in a couple scenarios.  On burned or rotted surfaces of the tree the outside wood needed for a hinge may be soft and offer little or no usable hinge material. Other trees may be hollow, limited the placement depth of the hinge into the tree. With either of these scenarios, the sawyer must look at the available wood or the lack of and make sure there is enough for a sufficient hinge to be established. A hinge may be sectioned or open in the middle, similar to hinges of a tall door however and still offer steering control and safety. On larger trees especially, two hinges can be formed, one at each side of the notch. If the tree is hollow and the notch extends back into the hollow, the two hinges located on the sides will still be successful to direct and support a tree as long as there is not too much side lean. Hollow trees, if you can establish a working hinge in the good fiber it only means you have less to cut.

 Hinge and Hollow        Two Sides Holding      

Trees with rot in the hinge area, rotted or unstable fiber cannot be felled from the ground with complete confidence and control. Without hinge control, safety is a questionable issue. If a tree has lean in a favorable direction you may be able to notch and back or bore cut to fall the tree safely. If the plan information has obstacles or hazard situations that can affect the fall, you must decide to leave the tree. It will have to be taken down from the top by bucket, crane or a climber that can suspend from another adjacent tree or structure. If the tree base is unstable it's not safe to support a climber either. Leaving a tree in the woods you can't safely plan to cut means you have to mark off the area  - at least the height of the tree or as is usually suggested, two tree heights so no one enters the area. In a residential area mark the area well, especially any walkways, until the tree can be removed. Don't leave a situation for another unsuspecting person or animal to enter the zone and be surprised by the tree falling on them.


The commonly used Definition of a Hazardous Tree is one with a Target. If the tree shows any sign of instability and there's a chance of people or property damage, it's a Hazard Tree! Stabilize it or remove it as soon as possible.


Practice your saw cuts and become proficient in making notches and hinges on practice blocks or stumps before ever attempting to work in rot or burned situations. Your chainsaw must be sharp and in perfect running order. Read your owners manual and be familiar with its content. Wear your PPE and if you are not comfortable with the plan you are able to devise... Call someone who is.


Good Sawing!


The ForestApps eBook, "The Complete Guide to Chain Saw Safety and Directional Felling" is available from our website and downloadable from  . We have recently completed filming some very good video footage that we hope to have out in the next month or so regarding a few storm damage situations. So stay in touch with our website or by ChainPoint.


If you have questions or feel other explanations are necessary regarding this article there are training programs available from Forest Applications Training to better your understanding. Write to Tim Ard or visit our website


(c) Copyright 2010 Forest Applications Training, Inc.