Tree Damage

[OneClick]

I always carry some 1" webbing to attach my tarp line since I really messed up a tree on my first trip...zing-it cut into it like a hot knife thru butter. Sap everywhere. I caught it right away and used some birch bark to wrap around and protect it, but the damage was already done.

[SweetLou]

I've been thinking about this for some time now. I have thought about using tree huggers for my tarp also. Especially now that we are using skinnier and stronger line. The skinnier the rope, the higher the PSI on the trees.

Another reason I have thought about is not only for the trees but to keep the rangers happy. I'd hate for a ranger to tell me my hammock is fine, but the tarp needs to come down.

[MDSH]

Simple solution.
If you put 3-4 sticks vertically under the woopie,it will distribute the load, vertically.

That is such a good idea.

Mike

[ibgary]

Thank you. I thought of it myself.

[nothermark]

Simple solution.
If you put 3-4 sticks vertically under the woopie,it will distribute the load, vertically.

They had better be *big* sticks. You have two problems. One is the surface area of the strap/cod/stick. Wider straps spread the load reducing the pressure per unit area. You need enough wood to equal the area of the strap.

The second issue with the stick idea is the flexibility of the sticks. a 1/2 in stick will flex enough that not a lot of load is transferred at the end of the column. I'm not running numbers but as a woodworker I can say clamping cauls 2" deep are not uncommon. They have the same problem - spreading a point load from the clamp over a wide target - the boards being glued together.

Seems to me by the time you mess with all that wood it's easier to carry some 1 or 1.5 in webbing. ;-) YMMV

[Cannibal]

What the sticks do do (), is change where the forces are going. The danger, as I understand it, to trees comes when the bark is girdled (think that's the word I'm looking for) all the way around. This chokes off the tree's abilities to move nutrients up and down. By placing sticks between the wrap and the bark, you are removing that girdle and consolidating those forces onto a smaller area instead of wrapping the tree.

Not saying the damage won't still be present, but it should be less critical damage to the tree.

I have no clue what I'm talking about here, so I fully admit I may be wrong. It just seems to be logical.

[Clauwitz]

A tensioned line closer to 90* will transfer the load on bark more horizontally, where the bark will have the greatest protective effect than if it had a stripping motion with a downward pull. That was my thinking anyway. A cut heals faster than a tear, right?

I would agree that an equal force horizontally, rather than at an angle downward, would probably* be better. Unfortunately, each tree still must support one half the weight of the hanger. Increasing the tension on the suspension doesn't decrease the vertical load, it only adds horizontal load. To a point, I suppose increased tension will load the strap more evenly across it's width. Will the more even loading offset the additional stress applied because of the increased tension? There might be an optimal point, but I don't know what it is.

But I thought the load on the bark became dynamic because there was no load before and a human being attached via hammock afterward -- like the live load that is calculated in architectural specs. Merely attaching a line or straps causes breakage, sound, and heat. There is movmeent while we are in the hammock. A good portion of hat energy is transferred to the trees.

Like I said, I was mostly arguing semantics. You are correct that a hammock hanger is a dynamic load since we move and sway. That energy is dissipated by air resistance and internal friction (caused by deformation) in the hammock, suspension, and tree. I suppose I was just positing the dynamic portion of the forces is very small; what we are mostly concerned with is the static part.

Perhaps I would have been better served by saying friction is not ONLY a dynamic event. A completely motionless rock on a hill is experiencing friction, but since there is no relative motion there is no energy dissipation.

Also, I was probably talking around the definitions of force and energy (which aren't the same thing). Force is the ability to do work, while energy is a measure of work done (force times distance moved). I could go on, but I'm boring me now and everyone has stopped reading this post.

*probably assumes the compression strength of the bark is higher than the shear strength. That might not be true.

[FLRider]

Due to ignorance on my part (read: "I am not an arborist, nor did I stay at an Holiday Inn Express last night."), I prefer to go with 1" webbing. It seems to be the best compromise between weight, bulk, and protection of tree species that may or may not be harmed by my impact on them.

I'd prefer to avoid being "that guy" who harms the trees that all hangers depend on (and most hikers like having around regardless). Since I do not have the knowledge necessary to ensure that I can make the correct call about whether to use tree huggers or not every time, I use them every time.

It's an insurance policy against possible dangers to both the outdoors and my enjoyment of them--the same as my headlamp and first-aid kit are.

[Barefoot Child]

I agree with Cannibal...it depends on the species of tree, but just in case I am going to use 1" strapping for my tarp from now on to alleviate any doubt, along with not hanging from thin barked trees at all...problem solved....at least, that is the theory.

And because we are discussing this topic in the first place, tells me that we all care enough to talk about it and possibly do something to prevent any damage what-so-ever from occurring in the first place...thanks mates

[Riddled]

You could also put some closed cell foam between the strap and tree as drawn on page 53 of the ultimate hang. I am not a scientist, just a country boy that likes the woods, but I feel a foam padding would have to help.