Chainsaw Fail Video: This Poor Guy...

...needs to take a class.  Here are the basics for looking at lean/weight on a tree and figuring out if you can handle it, or need to call a guy with a bucket truck. (If a tree has a chance for hitting an improvement, you don't take chances! You call the guy with the truck!)

Lean Limit Basics

There is an easy set of guidelines for limits of lean you can handle on a tree you need to fall. Measure the distance from the back of the hinge to the back of the stump. Say it's 1 foot. That will be your segment length. Measure the height of the tree. If it is 50 feet tall you have a 50 segment tree. On 50 segment trees the limit on back lean you can handle with wedges is about 10 feet. (Not Fun!) That is true if the wood is solid and has good fiber strength. Eastern hemlock will be much less than that. Old black oak may be much less. Every tree has its own secrets. If it's taller by 10 feet, that's a  60 segment tree. Now the limit is about 8 feet.  If it's shorter by 10 feet to 40 segments,  the limit is about 12 feet. Tipping trees near the limit is hard, and the hinge may fail, making the tree go over backwards. A 1" wedge will move the top of a 50 segment tree 50 inches; two stacked 1" wedges can move the top 100 inches. Figure your height and number of segments on all trees that need wedging over and you will know if you can get it with the thickness of one wedge. Use parallel wedges to increase your lift.  Three side-by-side wedges will push three times as much weight as one wedge.

Your most important application of this skill is to know your limits on side lean, so you don't have the hinge fail. If 10 feet is the limit for back lean on a tree, the limit for side lean is less than 1/2 of that! That is because back lean is pulling equally across the hinge, but side lean is pulling hard on 1/2, and compressing the other half. Going too far on side lean will cause the hinge to fail, so don't push that at all. Watch some videos where people have side lean and do not pull against it. The tree will go where it wants! Look at all your trees from two vantage points to make a quadrant for weight and lean. You will then know within 90° where that tree will go if it is severed. You need to know that in case the hinge should fail you; then you will know where to step to avoid being crushed.

How do you determine the amount of lean? Step way back from the tree, at 90° from the fall line. Put your hands up in front of you and surround the crown. Bring your eye to the middle, and bring a line straight down. Note that spot, go to it and pace in to the stump (or measure).

PS: It looks like about 8 feet of back lean on this tree, and he probably could have wedged it over, but he used only one wedge.  You cannot pound one wedge against that much weight.  Instead, he cut the hinge thinner from the front, with predictable results.  If only he had watched a few of my videos he could proudly say, "I'm a logger!"