plungging the spar

[murphy4trees]

How many of you guys are plunge cutting when felling?
How about in the tree?
I started plunging while working down the spar and think it is far superior to the old backcut in this application.
This may apply to the topping conversation from other threads, that is in minimizing spring loading the trunk when felling the top. And I haven't tried that yet. I would think plunging would work well, especially with adding a center plunge. This could allow control of the exact amount of holding wood.
And I do have a concern about loosing control of the saw when plunging while aloft, though that hasn't happenned.
Any thoughts or suggesdtions on this technique are appreciated.
Thanks and God Bless,
Daniel

 

[Kevin]

Daniel,
I don`t see a need for it unless the spar is under considerable stress.

 

[FBerkel]

Kevin,

Gives you a chance to put your saw away, get braced before all heck breaks. Also, can fine-tune the exact amount of wood in the hinge, then cut through the last fibers bridging the back of the cut using a handsaw instead of chainsaw.

Taking down a big c-wood today, permission granted by customer to demolish driveway, which is to be replaced anyway. A rare opportunity to enyoy a little serious destruction...

 

[coydog]

could some of you elaborate on your methods of plunge cutting?

 

[murphy4trees]

I've got some video tapes on plunge cutting made by International Paper for loggers. Two tapes called "Coaching the Professional Chainsaw Operator Workshop"... a little redundant and some good pieces and a thorough explanation of plunge cutting.
And the more I plunge, the better I like it..
God Bless,
Daniel

 

[Treeman14]

murph, Are you talking about plunging for the back cut or plunging through the center of the hinge?

 

[Kevin]

Coy,
Plunge cutting is how you take out a leaning tree that is under stress.

Make your face notch.
Cut a tunnel behind the hinge by boring straight through the tree.
Saw up to the hinge then backwards leaving a heel.
Pull the bar out and cut the remaining heel.
The tree will fall.

Don`t enter the bore with the upper nose of the bar or kickback will occur.

 

[coydog]

thank you Kevin, your explanation is illuminating.

 

[John Paul Sanborn]

I use bore/plunge when I have a tricky fall or pull. Like Fred said, lets you get everything just right then you juts have a small tab to cut off.

I've done it on a number of unfavorable leans before I got The Winch. Set everything up, fethered the wedges in nice and tight, cut the back strap and pound the wedges till she tips over.

 

[Kevin]

Most of my trees are leaners on the cable because of wind or decay and by using a plunge cut then taking the little bit of wood left at the back cut there`s little or no stress left in the tree which almost eliminates surprises.

 

[murphy4trees]

Brett,
Thanks for asking.. clarity on AS is really important to me. Sooo..
The question is how many of you are plunge cutting (the backcut) when working down a spar? And I made a further comment about plunging to control spring when removing a top. I would think that a center plunge, that is removing the center wood of the hinge, would be an additional way to reduce the amount of holding wood and thereby reduce the spring effect.
So it turned out we had a bit of wind this afternoon at around 3:30 PM and a 90'+ lead of a tri-lead tulip, that had some decay and included bark, let go.. it fell across the street and took out the wires and landed right across the hood of a 5 day old car.
I gave the customer a price on cabling last year and assured her it was only a matter of time without the cables. She didn't want to spend the money.. now it's gonna cost cabling x4 to remove the tree.. what a shame.
Anyhow, I ended up plunging to take out the top of the smallest lead, which was leaning back into the yard... Needed to get that out to make room for a speedline for the big remaining lead , over the street, before they put the wires back up. Otherwise the tips wouldn't have cleared the lines, which would mean lots of rigging.
Anyhow I was using an echo 3400 with a 14" bar. The top was maybe 11-12" with heavy head lean. The first cut was the bore straight through the center.. lining up the hinge. The second cut was the top cut of the open face notch... then after finishing the notch, the backcut. She let go with very little spring and just about about zero chance of the trunk splittting. It worked really well and even though I was tied into the big lead and had the lanyard around a side branch, the plunge cut made it extra safe... Always a good feeling.
So for the small stuff.. say under 12", it seems like making the plunge before the notch is a good idea.. what do you all think?
God Bless All,
Daniel

 

[Kevin]

I don`t think it`s a good idea.
Where are you making the bore... in line with the back cut or below?

 

[murphy4trees]

Kev,
The bore becomes the backcut.
Daniel

 

[Kevin]

Like so...

 

[murphy4trees]

Not exactly.. my backcut usually is pretty close to level with the floor (would that be the apex?) of the notch.. otherwise you got it.
Daniel

 

[Kevin]

Sorry, that`s the logger in me.

 

[Kneejerk Bombas]

I'm not a big fan of this type of cut. Besides being slow, if a peice is fairly straight and I don't do a plunge, as I backcut I can see which way it is going to go. If it moves in the intended direction, I can continue cutting. If it moves back, in the wrong direction, it gives me a chance to take action, while the hinge is still thick.
With a plunge cut, if it unecpectedly moves back, you are in the unfavorable position of hoping the hinge doesn't fail, your saw's not pinched, and that you can get a wedge to work the peice back over center before it breaks.
Also using this method on hazard trees, is even riskier. To correctly do this type of cut, you need to calculate the amount of holding wood to be left. This can't be accurately done with rotton wood. With rotted trees, I would make the notch, then the hinge size is determined by when the tree falls, as the backcut is made.

 

[Acer]

I've used this technique as in Kev's diagram. I have run into problems when I used it on leaning crack willow, when the bar got trapped in the plunged cut. Has that happened to anyone else? I presume I must have taken too much away from the hinge and the weight of the tree crushed the hinge wood, closing the cut on my bar.

 

[John Paul Sanborn]

On a big tree I will make the face first, then do the plunge, (The apex is the wedge tip of the face cut, or the corners of the smile.) inline with the apex.

The plunge will start well back from the hinge so that I can get the bar all the way in and then ensure an even hinge.

Then start setting wedges as I work back to make the tab.

When down to the tab, or back strap, wedges are pounded in further to start jacking the treeup.

Cutting tha back is usualy slightly below the plunge, so as to reduce the chance of fibers catching the saw as the tree goes over.

On heavy leans it will not go right away and further jacking with wedges is needed.

----

When felling a top without a pull rope on it, I prefer to have a deep notch, to help unballance the load towards the desired fall direction.

This will usualy make the back too narrow for a plunge.

Now If you have some very good sawlogs, or veneer quality hardwood, you can add a few inches to the log by plunging to set up your fall, then plunging the face so there is minimal holding in the sap wood. Then you will only have the splinered fibers out on the edges.

 

[Acer]

Originally posted by John Paul Sanborn

The plunge will start well back from the hinge so that I can get the bar all the way in and then ensure an even hinge.

Then start setting wedges as I work back to make the tab.

If I remember correctly, the ones where Ive had problems were bigger than the bar. The order of play was..cut notch..plunge in on one side, form hinge, cut back to leave tab..repeat on other side ..cut tab at back. The first plunge was OK, but the kerf would close on the plunge cut on the other side. I didn't use wedges because I thought the tree would be supported by the hinge wood. (there was around 1.5 - 2 " of it). I must have undersetimated how cr@p willow wood really is, with the weight of the tree compressing the hinge enough to close the kerf.