Cutting Sequence on Face Cutting Large Branches

[ward]

Situation

Suppose you are rigging out a large Deodar cedar (4 ft. dbh x 80 feet tall), previously topped and now with a candelabra of thirty foot trees in the upper crown. Large branches extend outward from the main stem, having a two foot diameter. You want to get this tree onto the deck quick but you have to rig things out properly. All your rigging in place—a block, drop rope, GRCS, etc., you now are ready for the face cut. You are worried that the saw will bind but you don’t want to make too small of a face and have the limb explode on you.

A Modest Proposal

I propose a cutting sequence for a face cut on large branches when rigging them from above or below. The standard technique for a face cut on a large branch consists of a well positioned climber cutting the face cut from the bottom of the branch with the top of the bar chain followed by a similar cut to finish the pie. There are two problems with the standard technique: first, to hoist a large saw upwards through the cut is often physically taxing, particularly over the length of time required to cut a face on a large branch; second, the possibility of binding the bar increases exponentially as the face is being cut. To mitigate these problems, I am here proposing a cutting sequence which is physically easier and safer to accomplish and which decreases the probability of binding the bar in the cut.

Bore Cutting the Face Out

In the face cut the climber uses a bore cut across the piece and in a line perpendicular with the falling direction of the piece. Now the climber cuts downward towards the bottom of the branch, allowing the weight of the saw to do the work. Before finishing the cut—and this is contingent upon the kerf cut remaining open—the climber stops the cut and withdraws the saw.

The second cut (the “pie cut”), the climber again bores in to the piece and drives the bar through until it meets the first cut while establishing the appropriate angle of the pie. Next the climber cuts downward at the pie angle and finishes the cut. The virtue of this cut is that in conjunction with the first cut it opens some kerf space that will release stress on the last strap of holding wood as the saw finally cuts through, thus eliminating some of the bind that can occur with a standard felling cut

Last, the pie remains and the last holding wood is cut from the face cut and the face falls downward.

Felling Cut

In most cases a simple downward cut is adequate to fell the piece, but it should be noted that (as with all heavy head leaners) a bore cut can be used to eliminate barber chair. The circumstances will dictate what is best.



Now, this technique which I described is one of several cuts that can be used on large branches. Jerry Beranek describes several techniques such as the “Coos Bay” which can also be used on big wood. But where there is limited possibility for movement around the big limb, where your work positioning is cramped, this may be a good cut. I do not claim to have discovered this cut (because I am sure that brighter minds and harder workers than I have already put it to use) but merely to have here described it.

What do you think? In particular, do you think that this cut does, in fact, eliminate bar bind? My experience has been that it does, but it is hard to quantify. I would greatly appreciate any input and criticism that you have.

 

[Gord]

Welcome to the forum and thanks for posting a thoughtful first post.

I think that we'd all agree that lowering entire 2' diameter cedar limbs is a little ambitious. However this discussion isn't just about lowering them but cutting them off safely. In my opinion and experience, boring large extremely weighted pieces on the underside can be dangerous as if any error is made in the cutting the saw is really, really stuck. Especially as you note, the climber is usually not in the most comfortable position anyways, making the chance of cutting accurately all the more difficult.

I prefer to make a shallow face cut on the underside, cutting carefully and reaming the cut as I go, beavertailing both sides of the top individually and then making my final backcut a few inches behind the beavertail cuts on large very loaded limbs.

 

[ward]

Thanks Gord for your reply.

I agree that one must take caution on big wood and I'm sure that you too have gone over the limit once or twice.

I liked your concept and I see that it does have applications. It has all the advantages, on the other hand, of Jerry Beranek's "Coo's Bay" plus the direction made possible by a true face cut. But I think I see a problem in that you'd have to change tie in positions to get around to beavertailing the opposite side of the branch or, more dangerously, have to reach over the limb you are cutting to beavertail the opposite side.

The advantage I am proposing in the above cut would eliminate changing your tie in position: all the cutting is done from one position AND you are not reaching over a branch.

My problem is that I haven't used it enough to know if the success rate I've had with it (so far 100% on about 10 big lateral branches) is confirmation that it does, in fact, reduce bar bind or is it a mere coincidence.

Stumped in Stumptown.

 

[southsoundtree]

Seems like high rigging point with the GRCS would allow them to be faced on top and lifted up a bit, then lowered, for 29 out of the 30 cases. I'm guessing that this is not possible though, for one reason or another. I suppose that this would mean climbing up and down a lot.


For dropping the tops,
Seems that a smaller than standard face cut would suffice. This will reduce bar binding. Maybe use a smaller saw for easy of getting the face accurately cut, as needed. Then bore in with the longer bar and cut upward. Finish with the backstrap from the outside, maybe by handsaw to allow you to get your large saw away.

Have you done this face boring? Sounds like you are trying to bore into something that would be difficult to avoid the top kickback corner of the bar because you would be on the underside of the workpiece.

Seems like as soon as you finished the bore cut (and fractions of a second before, as the remaining wood to be cut starts compressing more and more), the limb would settle right onto your bar binding it.

You might be able to just do all from one side with one saw, if you face is smaller. I attached a diagram of how I would do it.
First the small facecut.
Next cut down on the near side to allow the roll-in for the bore cut, and establish hinge, then cut upward to the backstrap (not in pic).
Lastly, trip the backstrap from the top downward, maybe by handsaw to allow you to exit the immediate area easier, if needed.

 

[Roger_Barnett]

Re: Cutting Sequence on Face Cutting Large Branche

Good thread. Sean, it's more work to lift a branch. Of course, if it's the best way to get the limb down, go for it. (as long as there's a GRCS in use.)

To avoid barber chair (especially in smaller wood with no room to bore), I utilize Gord's method, though my hinge is more triangular shaped with the apex facing 180 opposite the hinge face. No need to bore the way I do it, just cut at a 45 degree angle to the hinge, on both sides, progressively deeper and deeper, than finish from the back. In my limited experience, it's been as effective as boring the backcut(See D Douglas Dent's "Professional Timber Falling"

Ward, I've done what you state a couple times, and like it. But it's tricky, as SS described.

Also, to reduce barber chances, I'll face up the limb at maybe a 45 degree angle, or more if its tied far enough out to support it and help induce a swing.

Also, on lighter long limbs, I'll place a deep open face, with a varying angle of hinge depending on where the limb needs to go. Then, I'll continue enlarging the depth of the face with no backcut at all. This is usually only done when free dropping a limb, to get it to fit in a confined area. Works well with a wood like douglas fir which has great hinge holding qualities.