Gunning

[Tom Dunlap]

In the hollow tree thread, gunning sticks came up. I've done this a few times and it isn't well known in arbo circles.

Jerry Beranek shared some really good details with me that I'll pass along.

The way Jerry described gunning is to start off with two measuring tapes or a long length of low stretch string and a stake. Walk out to where you will lay the tree down. The further you get out, the more accurate you can be but it gets awkward beyond about 25'. Put the stake in the ground. Using string, half the string and tie an overhand knot large enough to slip over the stake. Take the two ends back to the stump. Make sure the ends are exactly the same length. By placing each end on the sides of the tree you'll be marking the apex of the face cut. You can move the two points up and down to position the face for easy cutting or maximum yield.

Using a tape is the same process. With a diameter tape or logging tape you can hook the nail on the stake and measure to both sides. This is the most accurate and can be done by one person very easily.

Gunning sticks work from the tree to the felling path. Two pole saw sections will work. Hold the tips together and move the butt ends around the tree to locate the apex.

I'm sure there are more parts of gunning that I've left out.

Tom

 

[John Paul Sanborn]

What ai would add is take is
after the knot is tied and the string staked out, clip the ends of the string off to ensure they are even.

If the two legs of a triangle off the hypotinuse are equal then the opposing angles off the base will be equal.

 

[Stumper]

Nice explanation---Gunnery Sgt. Dunlap. I understand how this can help in precision felling but it doesn't seem like something I have much need for. I don't know if that is because I have a welll calibrated eyeball or just don't drop big enough/tall enough trees for 2 or 3 degrees to matter. I suppose I would be jumping on this if I were just getting started. Thanks for posting it.

 

[Greg]

Great explanation Tom, never heard it described like that. I think that most of us working residential jobs have looked at a tight squeze of a drop and elected to peice it down instead of taking that $30,000. risk (RBTREE?? has a great pick of a monster he droped in a tight spot --search "tight squeze" I think). Might be able to build my confidence a little with this method.
Greg

 

[Toddppm]

Interesting, never heard it described before. I have a good eye of where the notch needs to be. I always used to do my bottom cut first and then the top , but seemed to cross them up every time, so now I do the top first and it works better but I have a hard time getting the top cut started in the right place. Maybe marking the center will help? Also that notch was made with a 066-32" bar about 4ft. off the ground! That didn't help.

 

[geofore]

If you are showing new guys where you cut and explaining why it is nice to have a piece of chalk like the kids use to draw on the sidewalks, walk back away from the tree to the spot you want to land the tree, look back at the tree and have one of th guys draw a smiley on the tree facing you. His smile goes from side to side within your view and the circle for the face is the same as the diameter of the tree. have the guy walk back and look at the smiley. From peak to peak of the smile is your bottom cut, flat, from his forhead or his eyes to the bottom cut is the top cut and you know the back cut goes in the back an inch or two above the smile. I also carry the chalk to mark the chain when I touch it up to know where I started to touch up the cutters so I don't go over them twice.
That is about as technical as you need to be if the tree has a big landing zone and your guys aren't good with english, they will get the picture.

 

[Dave]

On trees that I do gun, I use the logging tape- it won't stretch as much as a string. If it's tight enough to be gunned, I'd rather not have the error from pulling one side harder than the other. Maybe a length of Spectra??????

 

[tree monkey]

why not use the sight lines that are on the saw? thats what there there for. practice falling polls on a stake to build your confidence.you can check yourself as tom explained. use a string with low stretch, like throwline. i use a common notch like is shown in the hollow tree. but often add a humbold to make an open face. this way the notch never closes' and hinge holds till the poll or tree hits the ground. this gives you control of thee tree for a longer time.

keep in mind a severly hollow tree can callapse. i'm lucky to be alive today. it pays to work with a buddy.

later scott

 

[Kevin]

You could compare it to shooting a rifle.
Bend over and shooting the rifle in a certain direction will get you close but if you get behind the same rifle and line up the sights it will get you dead on.
In most cases the saw sights are adequate but if you need to thread the needle and drop a tree in a narrow window the other gunning methods are more accurate.
It will teach you to cut a proper notch and illustrate how important it is to line up the corners of the notch.

 

[TheTreeSpyder]

i think it works to reinforce what you should see anyway. So it helps train the amateur, keep an apprentice in line etc. When a seasoned pro has to 'thread the eye of the needle', and has so many things to contend with; they may find themself using this simple technique to reinforce what should be obvious. With so many things to contend with at one time in a tricky situation, mechanically double checking such a thing would allow you to rule something as more of an absolute and concentrate on the other factors more, now with mind quieted about this quotient.

i think Tom's repeated point from Mr. Beranek of the longer gunning 'sticks' plotting a more accurate fall very insightful. Also, point out his refrence to non-stretch lines; for this trick to work both 'legs' of the gunning 'sticks' must be equal. Any stretch, slack will throw all that off.

Originally posted by The Buzzard
It will teach you to cut a proper notch and illustrate how important it is to line up the corners of the notch.

i think that the most interesting thing is why it works (as usual!). i think everything else being equal the outermost sides of the hinge place the the most leveraged pulls on the lay of the spar. So, therefore, measuring equidistantly from these two most leveraged pulls, finds the meeting of the balance of their pulls, the center of the lay.

Just as the longer 'guns' give a more precise prediction of lay, by drawing a sharper angle; i think that a hinge made in a narrower part of the circumfrence of the spar, would gun to a sharper more accurate angle. Especially on a spar that is well balanced across the hinge . While, a wider hinge strip that provides more leveraged side to side control for side leaners, but draws to a less focused point. So, i try to use a narrower hinge on more precise, no side lean type drops, but on ones with a side lean i try to maximize the amount of leveraged control on the lean by placing the hinge at the widest part of the tree, but calculate some loss of precision in the trade.

i think that trees that are flatter on the sides, make less diffrence how deep the hinge goes, for the outside, most leveraged pulls are roughly the same due to the flatness!! ie. the hinge strip is roughly the same length. So, face cutting deeper on these trees would only help in undermining the horizontal CoB, for allowing safer fall if the CoB on the horizontal plane is over the stump or back away from the fall.

i like standing next to the tree, facing the lay squarely and cutting down into the tree, at a perpendicular angle to my body, bar, squarely facing target that i am facing. i usuall cut almost all the way, cut the bottom to apex point of facecuts, then cut down to release notch without pinching bar, meeting the bottom cut squarely. Crossing cuts and not meeting them precisely makes a false face, invoking dutchman type forces.

i think that as any hinging discusion, studying it cannot disclude decay effects. i don't think that you would gun to a pocket of decay, or where you have to cut out because the bar is to short to reach across; only to solid wood of the hinge, at the outside, most leveraged points of pull, in an everything else is equal example.