climbing with the wind

E. regnans when growing in a stand, naturaly "thin" in a number of ways. One of those ways is to break in half in high winds. It is the trees that have some defect that have an increased chance of failure.
The outer layer of bark and sap wood is an integral component of the E.regnans trunk flexability/strength. When falling Eucalypts it is important not to cut the hinge off on one side. Unlike softwoods where it is ok to wing cut, an over cut on a hinge will increase the loss of control of the tree. If whilst being assessed for a hardwood falling ticket you cut the bark on the hinge of the tree, you would fail that tree. The bark is very important for the control in alpine falling.

Because of the very long slender nature of the E.regnans this species is more telling of this characteristic than most (200' plus and 2-2.5' dbh).
If tha gaff placement was to damage the bark (tension side), at a point of some other defect in the trunk, I did feel that a mid trunk failure could be possible.

The top 20' of the tree would lay almost flat to the ground during a gust. Where I was, went to about 40 deg with a significanf bend through its length all the way to the ground. When I looked down this increadable bend (with eyes like a mad cat) I realy thought, "this is not good", and was glad to have spured to the side and under the tree.

May be I should satisfy my curiousity and set some trunks up to test. When I was logging we sometimes broke logs pulling them around bends in the snig tracks. I didn't take much notice of where they broke, we simply cut more stumps so it wouldn't happen again.
 
If its a removal needing hinging and correct placement of falling limbs and lowering, I don't like to work in the wind. If it's calling for gusts like 20 or 25MPH or above, I don't do it. I don't like gusts blowing the limb or top back onto my backcut and me fighting against it to push it the right way.

It's been a really windy end of winter here. More wind then usuall.

My brother threw this question out to me the other day. He stripped out a tall white pine on a windy day. He said this, say you stripped out a tall white pine while spuring up from the bottom. Say you left a bare trunk and had maybe 1/5 of it left, only in the top. Would the tree be more prone to snapping off in a bad wind storm, then if it where left with all its limbs?

I thought about it and decided that yes, the tree should be more prone to snapping with it's bare trunk and only it's top left. The bare trunk would cut through the wind and the top would be recieving all the push. If the tree had all of it's limbs, the trunk would recieve more equal pressure from the wind. With only the top catching the wind, the trunk would bend more, increasing the risk of mid trunk failure.

What do you guys think?

I'm thinking it's kinda like a fishing pole. With the tree having all it's limbs, it's like a fishing pole with all it's eyelets putting stress more evenly down the pole. With only the top in the tree, it's like the fishing pole only having one eyelet just at the tip of the rod.
 
The tree would surely have an increased chance of snapping, because the trunk below the remaining head would not bend as far. This would in turn, demand a higher flexability and strength requirement of the remaining head/limbs. Given that they had grown and developed with a more forgiving environment, I feel they would be more likely to failure.

I see the "fishing pole" as a good analogy. The unfortunate thing is that the trunk breakage points will always be at your position or above where you are removing the limbs.
The additional concern I have, is that the climber is potentialy creating a further defect in the tree where the gaff cuts in.

The one redeeming feature of lowering limbs in strong wind is that, the limb cut off does not reach the trunk for an impact. only the limbs directly upwind present a potential impact to the trunk. They simply fly like kites to the down wind side. With the whipping effect some limbs will actually sit almost horizontal to the lowering point, which raises other concerns regarding rigging.
 
That is a good point about the wind holding the limbs away from the trunk. I did a removal of a maple the other day and the rigging point had to be straight above a fence. But when the brush was lowered to the ground it was 6' or more over the fence due to the wind pushing it. It was a huge help for the crew!
 
the wind acctually helped me drop the tops out of some norfolk island pines away from the power lines....with out a tagline saveing alot of time and effort! when ur in the top of one of those and look down the trunk on a windy day ud swear it could snap anytime!
 
I do not mind climbing in the wind it has helped me out doing some jobs. Just the other day the wind was helping me lower limbs on a good size pruning. That and when I go up in the wind it keeps some of the more whiners on the crew I work for away. Not that do not like hearing,It is too windy to do that we can come back later all the time. Well up the tree I go and they go away.
 
Does anyone else find the fact that the Beaufort wind scale was developed by an Admiral in the Royal Navy and used tree movement, and failure, in winds?

The few times that I've climbed in very windy conditions but I do consider what is going on. In my mind I would think about how my load translated into a bit more wind load and how much the tree can tolerate. Would my load be the straw that broke the camel's back?

None of the 'wind trees' that I was in ever seemed weak enough to consider the effect of spiking. If I did think that was an issue I'd be out of the tree very quickly. That would be a very marginal tree.
 
R_Schra

Ok let me get this. Your saying in the higher winds you flop the top out to lessen the lions tail effect on the tree.

I was always wondering in even mild wind during take downs about the effect of limbing the tree on to way up and could the top fail. I would really like to hear more. Does anybody have anything simular?
 
I'm just happy once I've taken my weight out of the branch I'm on!! I think there is an element of increased risk when you work up to the top of a tree and do the top last as there would be slightly more mechanical advantage with the top acting as a sail, but when you think about the tree having built up enough strength to carry the weight of all the limbs, then it doesn't seem quite as bad... but then I always heave a sigh of releif as the top comes off!
if its a deciduous tree then we try to do big take downs when there's no leaves, but thats in an ideal world /forum/images/graemlins/grin.gif

the needs of the many outweigh the needs of the few... but I wouldn't risk my life to prevent a tree falling on a house if there's no-one home!
 
did an arbormaster training seminar last summer. The video they showed clearly demonstrated the dramatic increase in the risk of mid trunk failure by limbing on the way up. Just the loading of the falling top could cause it without wind! The lower limbs act as dampers to the forces generated by the top swaying in the wind or falling. Couple this with high winds or gusting and you've got a very real chance of failure.
 
I can see that yes. sounds like a battle between getting everything caught up as you're lowering it, and being safe, or getting everything on the ground and being risky!! Ken and Rip have some common sense between them [:D]
 
Using an only an absolute metric like the Beaufort for assessing tree resilience to wind doesn't make sense unless you also asses the tree. Trees that grow in high wind will be relatively safe in high wind. A tree is at risk to wind damage if its had neighboring trees removed, creating an edge effect, or if the weather is unusually strong. You should know the weather pattern where you climb. Ive found that climbing in wind can be a nice ride if you know the tree is sound and adapted to that condition, similar feeling to a sailboat.

Of course, if your concern is the trajectory of falling wood, the tree's reaction wood is not an issue.

-Ryan
 
Treehumper, you're saying the lower limbs act as dampers to the forces generated by a falling top (which makes intuitive sense), but if all the limbs are off (except for the top), isn't the trunk somewhat relatively stronger cuz it doesn't have to support the tremendous weight of all those lower limbs? So when the top is cut out and lowered, the trunk is a bit more whippy but isn't it better able to deal with the forces involved cuz so much weight has been removed along the trunk??
 
The weight of the branches is a compressive force that loads the tree vertically. With the lower limbs removed the top's sail effect is multiplied and the load on the trunk is magnified at about 1/3 the height of the tree. In effect it's like a long pry bar, the longer the bar the greater the mechanical advantage. I would imagine there is an offset but the increased torsional and bending force makes it much more dangerous. Add a defect at the point of peak forces and it's a disaster....

Anybody else seen the videos of the test done that illustrates this?
 
I'm not sure. I believe it was a computer model. I haven't been able to find it online. There was also data collected from trees that had failed during felling operations.
 
At one of the seminars at tci or isa there was video of trees blowing in high winds. the energy of the tree moves like ripples in water when a stone is tossed in.when you top a tree with lower limbs remaining there is more mas to absorb the energy and slow the sway. similar to the tree just before it is topped. once topped the stem now moves easier due to the lack of top to take up the forces.
 
I dont understand how an area of wind resistance at the top aquires more force by having the area below it reduced. That area was no smaller before the lower branches were cut, so it catches the same wind before as after. True, there is more shearing force just below the remaining canopy relative to the rest of the stem, but that area was experiencing that same force before the lower canopy was removed; if it didnt break then, why would it break now?

There might be increased shearing on that point if the wind had been coming from below and the lower limbs were breaking the wave-front, but this seems implausible.

I can understand how lower limbs would slow, or "dampen", the shock of a dynamic rigging load at the top; that's an excelent point, but unrelated to wind as far as I can understand.
 
It is similar ; the dampening with rigging and the wind. both create energy in the tree and limbs on the bottom help absorb or dampen that.
 
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