back strap cut, whats the point?

[flatyre]

excuse the title, i'm not rubbishing the cut, I have never used it but recently watched a guy use it and was left wondering why. I'm thinking of giving it a go on the next job which has a selection of straight fells and leaners. But I've just sat through a number of youtube videos of the back strap cut and couldn't see any reason to use it over a standard back cut. If you have cleared you work area and taken up a safe cutting position you should be just as safe? If a tree is going to barbour chair what benefit does the back strap cut offer?

[Mick Dempsey]

Amongst other things on sweet chestnut and some other trees it can prevent fiber pull and maximise usable wood.

[Daythe trees]

If cutting for production it preserves the timber and allows you to control when it falls. For smallish leaners where timber quality isn't an issue and I am in a safe position I bore cut the hinge and cut straight out of the back sometimes. The dog tooth also means the hinge acts properly rather than being shock loaded and affected by a barber chair allowing gravity, shake, helical twist etc to control the fell rather than your cuts.

[treequip]

If a tree is going to barbour chair what benefit does the back strap cut offer?

 

Errrrr

 

It stops the Barber chair happening (Barbour chair would be some sort of country sports felling)

[flatyre]

Errrrr

 

It stops the Barber chair happening (Barbour chair would be some sort of country sports felling)

 

glad to hear that, one less risk, don't understand the physics though. Do the fibres have time to stretch in a standard cut creating more risk of a linear split whereas a back strap cut shock loads the fibres causing them to split across the grain rather than with them?

[MattyF]

Trees at risk from barbers chair would be heavily leaning or weighted trees, or some times even light leans with say ash at the wrong time of year (usually around now ! ) so basically your putting in your back cut as standard felling cut and the tree starts to split before you have finished the cut leaving a proper hinge... The felling cut was on the face of this mess!

[drinksloe]

I take it a back strap cut is when u leave the tag at the back? Esp on leaning trees.

 

Quite important esp if ur working with more brittle hard woods that are leaning (or got a muppet on the winch, who tensions without being told).

If u cut the normal way at some point gravity will take over if tree leaning and thats why ur barbers chair happens, and can split and roll anyway or hit u with back see sawing upwards pretty quickly

Not nice to be cutting normally and see/feel the grain opening up along the stem as ur praying for ur saw to cut faster to get enough out for hinge for it to work.

 

In the old days the old school cutter would tie chains round a trunk so it could not split, that was when they laid the gub with axes and back cut with big cross cut saws, so could not bore in.

 

Another cut in soft woods at this time of year is ur sap wood cuts, bore in some cuts well below hinge each side, so it will snap off and not hold on and split the good timber at base of stem which often happens with large soft woods esp in spring time

[slack ma girdle]

You leave the strap or dogs tooth until last, so you have already cut through the fibers that might cause the the tree to split. It also enables you to change position to a slightly safer one.

[flatyre]

So its good practice from a safety point of view to use a back strap cut even if the tree is destined for fire wood. lesson learned. thanks folks

[drinksloe]

Thats a scary 1 matty.

 

Scares the hell out of me, only had it happen a few times and a few times caused by over enthusiastic winching.

Seen it happen to far more experienced cutter than me too

 

Not sure i'm the best at explaining, but basically on a leaning tree (willow ash, sycamore, chestnut, are ur classics) the weight of tree/gravity takes over before when the hinge is still to large/wide, so top of tree will move while hinge/middle of bottom is not moving, sending splits down the stem.

 

When it goes very back end will pivot and fly up pretty quickly almost taking ur head off, tree often then spins on the pivot point (looks about 20ft up in photo) and can roll either side, just got to hope u've ran to the right side (why so important to clear ur emergancy exits, 45 both sides)

 

Dunno if there is clip online of barbers chairs happening, mibee easier to understand when u see it.

A very useful cut on leaning trees, infact only cut for leaners (unless u put a far largr gub than normal in)