why is face only 1/3?

[woodfarmer]

A few more from last winter

 

[Huskybill]

I’ve done some really scary chit when dropping trees with no wedges. About 99.99% the trees lean to get the most sun light.

One straight tree was surrounded by pines. I got hung almost straight up. I was knocking 4’ sections like Popeye. Then the upper large limb showed up. I backed up, shut off the saw as the y centered my body. Lucky me.

My dealer gave me instructions on how to fell trees and steer them.

I had tall skinny trees to cut on a hill. I needed to drop some up hill. I waited for a windy day. As the trees bent up hill from the wind I back cut them.

Cutting frozen trees, felling them, after the back cut and they didn’t move I put the saw down and push them with my body. I felled 12” oaks with human power.

I was really good at felling trees but old age is settling in.

 

[Spotted Owl]

This place doesn't change much, does it?

Nope.

Stump sitting can be very therapeutic. There's still a few good people on here, they're just hard to find sometimes.

Yea, sitting by on a stump is therapeutic and entertaining. Some of the good ones aren’t so hard to find. You, Randy, slowP, Northman and some others, pretty easy to find when someone wants too.



Owl

 

[ChoppyChoppy]

Technically a face cord could be any figure really. It's often figured at 16" length, which makes it 1/3 of a cord, but it's not a standardized measurement.

 

[slowp]

Nope.




Yea, sitting by on a stump is therapeutic and entertaining. Some of the good ones aren’t so hard to find. You, Randy, slowP, Northman and some others, pretty easy to find when someone wants too.



Owl

Why thank you. I don't sit much on stumps cuz they either have a big wad of fresh pitch or are old and have ants and bees and splinters. (damn cutters didn't cut off the stump pull jagger thing) I prefer logs and blowdowns Now I live where even those are scarce! We do have some nice smooth rocks in some places.

 

[davidwyby]

The recipe for 1/3 cut is a good start point for beginners, but here in Australia, you approach every tree differently based on lean, wind, branch weighting, tree species and condition (live, dead, dry rot, termite, hollows, lightning scars)

While acacias, turpentine and spotted gum will hinge really well with a 5% hinge, salmon, brittle and scribbly gums can go "bang" with >50% hinge.

Dry rot and termite in the heart mean you might be dealing with just a 2 inch shell surrounding 12 - 18 inches of sloppy mud/pulp. (bloodwoods, blackbutt)

Sometimes the lean is 90 deg to the side of the fall direction, so you bias the hinge to be thicker on the tension side or it will crack and fall sideways.

Sometimes I'll "long hinge" a fall by rip cutting a a fall plank with a fall face up to 12 inches high and multiple fall cuts at the back (usually with a winch fall line)
When the fall direction is against the natural fall of the tree, and damage will result if it goes wrong, a winch line (and axis tether if needed ) and a thicker hinge is worth using a rope pole or doing scamper 5m up to attach a rigging point.
I've safely felled uprooted trees overhanging houses against 30deg leans and 30 knott winds. Proper long hinge technique is important as well as winch and tether lines. If you're asking a tree trunk to hinge back 30 deg to straight, and a further 10 deg to fall, it will snap without long hinging or multiple narrow fall wedge hinging.
Sometimes cutting a 60% face wedge can shift the centre of balance toward the side you want - but you want to be sure you know how tensile and flexible the species of timber is, and have enough room to wedge the fall cut behind your saw as you cut so it doesn't backfall.

Always watch the gap in your cut - face or fall, because a tree can have spiral grain, or grain tension, that will close up the gap as the saw cut changes the balance of tension in the trunk. Your saw cut gap will visibly change before the saw binds - and also tell you which way the tree wants to move.

You will feel, smell and hear when you are cutting dry rot, wet rot or termite. Stop and re-assess the fall.

When I started cutting dead and brittle Aus species here in CA a while back, these were ideas I had. I wish I had seen this post with real life exp with them sooner...I will give them a whirl.

 

[pdqdl]

In my opinion, no one has provided an exactly correct answer. Now I'm not argueing with anyone's input, I just think you have all been missing the point of that 1/3rd diameter face cut.

1/3 because there’s no need to cut extra wood. The face takes 2 cuts. The back cut takes 1. 1/3 will generally give you 80% of the diameter . Plenty of hinge.

I agree. It's that "plenty of hinge" concept that is important.

The best argument for using wedge and 1/3rd face cut is because (as has been pointed out above), you can be wrong, and then the tree will "set back" on the chain. At least in theory, you have chosen the face cut direction because of the lay of the land and the direction you need to have it fall. After that choice is made, you need to plan for how to best get it to go that direction, and also to plan for potential failure.

That fairly shallow face cut is more about the tree potentially going the wrong way than it is about getting it to go the way you want. By widening the length of the lever formed between the wedge and the hinge wood, you increase the effectiveness of the lifting force applied by the wedge, and you seriously reduce the risk of hinge failure, should the tree resist going the direction you wish it to go. Keeping that hinge wood as wide as practical without reducing the depth of the backcut puts you at 1/3rd diameter. Roughly speaking, that is.

Consider, if you will, that you might just choose to drop a 3 foot diameter tree that is 100 feet tall. It's straight and true, with no breeze. Theoretically, you should make a one foot deep face cut, then start a back cut. This will leave you with a theoretical lever on tipping the tree of 50:1. That's a 100 foot tall tree, with you working on lifting a 2' wide lever at the base with a wedge. Ok?

Now let's toss caution to the wind. Instead pf wedging that tree over with the recommended procedure, we'll make a 2 foot deep face cut, undercutting the center of gravity. Then a quick back cut, and we needn't wedge anything at all, right?

This will work, but it is fundamentally unsafe. Let's say that just as you start your back cut with only 1 foot of trunk diameter remaining to cut, a slight headwind picks up, and your tree now wants to go forcibly the wrong direction. Even if you make a bore cut to allow insertion of a wedge to force the tree against the breeze, your leverage at the base is now less than 1 foot wide, against a 100 foot tall tree. So you have cut your leverage in half, and you have doubled the lifting force applied to the hinge wood keeping the tree on the stump.

OOPS! BAD Plan! (panic ensues) Quick...Pull that tree with the rope. Oh crap. I never set a rope either, and the breeze is picking up. <cracking noise!> NO! NOoooooo.

...As your easy-to-cut-down tree flops backwards in the breeze onto whatever you were protecting.​

​

If the tree were perfectly balanced you would have a point. Few are. An error of judgement leaves the feller without enough wood to use wedges.

Yes, but you didn't explain how that was a problem.

 

[pdqdl]

I routinely cut trees with more than a 50% of diameter face cut. I did a 4' diameter trunk just last week, sending the perfectly straight oak spar down where there were no headstones in a cemetery. My face cut was at least 5/8ths through the diameter of the tree, and I was trying to leave the most "live" trunk sections as a hinge. It helps to know that the tree was heavily decayed and hollow, and that the entire top had broken off in the wind, leaving a very heavy spar about 35-40 feet tall.

Now if I was planning on wedging it with a 1/3rd face cut, that would have failed miserably. Almost no amount of wedging would have ever displaced enough upper trunk to get past the center of gravity and forced the trunk in the direction I wanted. Furthermore, had I set a rope at the top, any "pull" that I applied would have been less effective, as it would have been lifting most of the log from a hinge point on the wrong side.

By cutting a much deeper face cut, you let gravity help you pull the tree over, but you do lose leverage to save the day with wedges, should the whole plan not work out on a normal felling cut.

By the way: when I made my back cut on the tree above, my big Husqvarna got trapped when the hinge wood on the far side collapsed before the tree tipped. It was just a bit too rotten, and I had made the face cut just a bit too deep on the far side. The center of the tree, as you may recall, wasn't there anymore.
I had my tractor on site, though, and he pushed the ready-to-fall spar over in the right direction, as I pulled out the big saw from the pinch. All done, smooth and easy. No problems. I did use the wedges to buck up the fallen log, though.

 

[davidwyby]

Gerry Beranek talks about understanding hinge fiber. I got to thinking about how wood splits more easily when split parallel to the growth rings (I think this might contribute to barber chairing on the back cut). Also about which way is desirable to have the grain in an axe handle. They are more flexible to the side, partially due to shape, and I think partially due to grain. Finally, about how logs are milled to produce boards with different grain patterns for different purposes.

1/3 of the way in, the cut is relatively parallel to the growth rings. I think wood fiber holds and bends more (or pulls and compresses more) when bent flat to the the layers/rings. If the hinge is in the center of the tree, the rings/layers are 90* to the hinge/bending direction and it seems to me would resist bending more and be more brittle.


Species, species, species....

 

[northmanlogging]

Gerry Beranek talks about understanding hinge fiber. I got to thinking about how wood splits more easily when split parallel to the growth rings (I think this might contribute to barber chairing on the back cut). Also about which way is desirable to have the grain in an axe handle. They are more flexible to the side, partially due to shape, and I think partially due to grain. Finally, about how logs are milled to produce boards with different grain patterns for different purposes.

1/3 of the way in, the cut is relatively parallel to the growth rings. I think wood fiber holds and bends more (or pulls and compresses more) when bent flat to the the layers/rings. If the hinge is in the center of the tree, the rings/layers are 90* to the hinge/bending direction and it seems to me would resist bending more and be more brittle.


Species, species, species....

I see where yer going with that, except that its easier to split wood in parallel with the growth rings rather then across them, its just not very productive for fire wood work, way back in the way back machine when we could get "burn logs" culls from the mill that were well over 4' dia we would sort of work our way around them rather then try to split them in half (as we got older and more muscles/experience we would tag team them and bust them in half, but it was a butt load of work regardless)

 

[davidwyby]

@northmanlogging growing up there in the PNW we could split crosswise or with existing cracks. Eucalyptus (actually pretty much everything) down here laughs at that…gotta go parallel to the rings. End up with square FW instead of triangular. Some folks do it a bit too much IMO and make thin flat boards like what gets ripped off the outside of the log at the mill.

 

[davidwyby]

Almost cool enough to make a splitting vidja…

 

[northmanlogging]

Almost cool enough to make a splitting vidja…

gonna have to source some whopper rounds... and convince my Step dad to be in a video... one of those things isn't going to happen lol.

 

[davidwyby]

Japanese splitter stuck…twisted Euc.

Both stuck



Why stuck: flat cheeks


Weird, this one split easy(fresh green)…gorgeous wood

Not so easy



On the stuff that has dried for many years, there is an outer rind that is spiral grain and not too hard to split but doesn’t make straight pieces. Offset of the core there is usually some splittable wood. Then the core itself is usually impossible—noodle it. 30 ton splitter barely splits them…stalls, then the round explodes.

Coastal live oak. That wood grenade worked well in pine in CO…

 

[davidwyby]

Broken handle: back to that grain orientation thing…

 

[davidwyby]

While cutting burnt dead desert mountain trees it occurred to me that 50% would probably be a good idea so as to have the remaining solid wood in the hinge.