Felling a hollow leaner

jimmy

I'm going to fell a very large oak that is hollow at the base. It is about 5 feet across and has only approx 6" of wood rim holding it up. The tree is (very) alive.
I have already removed many of the high branches that could make it fall in the wrong direction so about half the weight of the tree has gone. There is a small building near the base which could get hit if the weak trunk collapses into itself when I start cutting. I plan bind the trunk above where I cut with a 25' tow strap, make a shallow hinge, then bore just behind it and cut towards the back of the tree to leave a few inches of holding wood, then nip that from the outside and run! Any comments?

Victor Lindsay

How did you partially dismantle this oak? Could you continue to dismantle, and then block it down?

jimmy

Some branches I just dropped without a rope and some by a bull rope installed high in a neighboring tree. The rest of the tree could be dismantled in a similar way, but it would be a very time/energy consuming process. In particular, there is a very heavy limb right over the shed I mentioned with not much to swing it off. It will be far, far easier to fell it in one. The area it would fall into is clear--no buildings etc.....that is if the hollow trunk doesn't do anything unexpected when it is cut, like collapse into itself or crumble on one side and remain rigid on the other.

Eric Frei

Your plan sounds good.

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Tony Knight

Without pics is hard to apply even a rough JSA, VTA and target assessment.
I agree with vl2007, if I thought that significant risk was attached to felling and blocking down presents a safer option (even if more labor intensive) then I would proceed that way. If I was unsure of either then the tree is beyond my capacity to access and I would asked a more experienced person for there on site view.

Half the weight of the tree has gone, is that from around the whole tree or just from the back leaving the face and felling direction heavy? Given the hollow structure of the tree, if possible I wouldn't want a whole heap of weight on the face creating a pressure point at the hinge and scarf.
Back release is the method I'd use, with a good hinge/step and strap, plenty of wedges, webbing strap or chain the barrel above and below the scarf if real bad. Lastly, any chance of putting a rope, cable or rigging up to further safety and/or desired direction of fall?

Cheers


Tony

jimmy

Thanks for taking the time, Tony. The weight I've taken off is from the sides and also the felling direction. There is no growth on the back. After reading your note, what I'm thinking is to just take a bit more weight off the face, put a line up to stop the tree falling towards the shed, and cut at the base. I can understand that without seeing the tree it is difficult to know what to advise. I guess the crux of the matter is whether the trunk is going remain intact while falling and thus push the upper part of the tree far enough away from the garden shed (which cannot be moved).

Brent Ferris

I have dropped a few hollow trees and all have remained intact during the cutting the felling stage -- although I have always removed as many branches as possible before felling trunk,. The only problem I have run into is the trunk pivoting into a hollow spot on the side forcing the direction of fall to skew towards the hollow, It doesn't sound like you have that problem,

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If you want an honest opinion, call Brent Ferris...because, Trees want to Live Too !
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Eric Frei

He already explained this is what he was doing.

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Tony Knight

Ta, I wrote it as it came out of my head in sequence, at worst I just re-enforced the method.

Cheers

Tony

Eric Frei

Not a good method for a back leaner though.

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Tony Knight

True, thats a whole different ball game, without a VTA if a tree was a back leaner I couldn't say how I would tackle it, many tools and methods in my box of tricks thou.
Cheers


Tony

Eric Frei

Check out this stump from another thread.

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Tony Knight

Forward leaner down hill (I commented on it in that thread). No scarf, certainly a high probability of the pictured outcome. Amateur cross cut fire wooders branching out into tree fell? (should be short lived anyway if they continue like that).

I don't take many pics at work and only just started since the fires so I only have few, here’s a back leaner bias to the back, plenty of targets and not much room, at least it was solid.

Cheers

Tony

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Eric Frei

Those aluminium wedges, what sort, how much?

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Tony Knight

G'day Eric, there Stihl, 800 grammers, what I would consider a double taper and roughly 10 inches long (I don't have one handy to measure at present).

RRP is $58.00 my price through my dealer is $50.00.

I find them excellent in comparison to the cheaper alloy versions, they hold form better on the head and when doubled up or stalled into uncut timber they resist bending. If the do bend they straighten in the press easily without fracturing. There a good thing

Cheers

Tony

Eric Frei

PM me a link or part number etc, I do not think I've seen these in the Stihl shops here.

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Tony Knight

Any problems sourcing drop us a line.


Cheers

Tony

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Brent Ferris

I have never seen aluminum wedges either -- could you share that info with me?

__________________
My business: Tree Pruning and Removals -- Strump Removals -- Advice -- Consulting -- Arborist Reports
If you want an honest opinion, call Brent Ferris...because, Trees want to Live Too !
We do great jobs, even in small yards.

Free Estimates Oakville to Oshawa - North to Bradford (Will travel further if cost of travelling covered)

Tony Knight

G'day Brett, no worries, i've got to head to town and the dealers late this arvo and I'll grab the stihl part no while there.

Regards


Tony

Eric Frei

Tony, I used to get ones that were just like this but shorter, about as much lift.

How does this one compare to yours for length and lift, I think the length is the same but lift?

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Tony Knight

I have dealt with NAA for a fare bit of gear over the years (the better half works not far away making P/Up easy). I have bought and used those wedges and they are the identical dimensions to the Sthil ones I use. However I find them softer and deteriorate quicker than the Stihl (maybe its just me??). I was down at the dealers tonight and got some part No.s for their range. The shorter ones are 190 grams (haven't seen one in the flesh). The cattledog lists all the dimensions except the lift, go figure? Ben rang the importers and guess what, none in stock to measure, go figure? Their in a 20ft'er waiting to be unloaded and he was going to let me know next week.
If you can't read the No.s I'll post them.

Cheers


Tony

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jimmy

That hollow leaner came down perfectly, exactly in the right spot!! I strapped the trunk above and below the cut and it held together OK while falling, then I cut backwards from the hinge and when there was about 5" of holding strap left there was so much lean in the tree that the top part ripped a spike of wood out of the bottom part, like a tooth extraction! Anyway, thanks again.
Jimmy

Tony Knight

I like good news... Good job.


Cheers

Tony

ArbTrain

I have been away for work for a few weeks and am just going over what i have missed on tree world - came across this thread.. great result.. best thing about the whole process , the bloke behind the saw wasnt sure,, he stoped ,, he had a think,, he had another think,, he got some advise,, he thought some more ,, he considered some others views,, he thought again , and then he did the job spot on,, top shelf,, im going to use this as a case study for my level 3 chainsaw courses.. ( if thats ok with Jimmy)..

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