1. ## Tree Damage

Alright everyone,
Let's not all throw stones at once. This is a speculative question and I'm sure some people are going to get mad but it is a scientific one. Does anyone have any proof that hanging for one night with an all whoopie suspension system (without treehuggers) hurts trees in any way? I've always used 1in tree staps but a guy has to wonder. I'm not asking about what non-hammockers think and their misperception about hammocks damaging trees so please refrain from those comments. Thanks for any insight

2. All depends on the species of tree.

I have seen my 1" straps leave marks after a single night. By the same token, I've seen cord based suspensions hung from the same spot for three nights in a row, with no visible damage after take-down.

I suppose the mantra for this topic is, the right tool for the job.

3. Why risk it if you don't have to? Stone can be cut with sand-impregnated string.

In my ethics classes I taught that superior beings have greater responsibility than inferior ones. What can a tree do to defend itself?

"Hey, stop hurting me!"

I never heard a tree say that but can imagine it.

In trying to move to a single line suspension system one of my goals is to load the gear more and the tree less: a single line holding both tarp and hammock stretched more perpendicular to the trees will distribute the load more evenly over the 1" strap width whereas before I could not even be sure of 1.5" nylon getting 1" of bite on the tree.

We hang by friction. Friction is a dynamic process of transferring energy in the form of light, heat, sound, and motion. The bark of a tree goes frmm a stady state to a dynamic one once it is loaded with a hammock and tarp. Where does that friction energy dissipate? How is the stress distributed? The more widely it is distributed the less damage is likely done.

In a SLS with nice tree straps some of the energy is transferred from the bark to the entire verticle structure of the tree, depending on how much tension one can crank into the line: the more tension the more the tree acts as a column and the line acts as a beam.

My youngest son is a big boy. I mean big.

He once put his hammock between a couple of trees that ... were not sufficient to the task. I think one of those trees will never be the same!

But as I sat there watching it unfold I realized the weight has to go somewhere since the ground is no longer holding it. If the weight was equally distributed between the two trees with a rigid beam then even the weaker tree might have stayed in column. Who has noticed the beam between the turtle stands? The beam is what makes it work.

Physics and a little metaphysics, right?

A ranger in Guadalupe Mountains NP once told me to take down my hammock. Perhaps that has shaped my thinking too much. But there are other things about the SLS that I like so ordered the last parts for it last evening.

Mike

4. Originally Posted by MDSH
In a SLS with nice tree straps some of the energy is transferred from the bark to the entire verticle structure of the tree, depending on how much tension one can crank into the line: the more tension the more the tree acts as a column and the line acts as a beam.
Because of the nature of rope (cord, cable, etc) it can only support loads in tension. It does not support shear, compression, or bending loads. It will NEVER act as a beam; beams can support shear and bending loads. Cranking the support lines tighter only applies MORE stress to a tree, not less. In general, each tree will support half your weight vertically, and then the remainder of the tension in the suspension will be supported horizontally by the tree. I refer you to the hammock hang calculator. If you DID have a beam (which as hammock hangers we don't) you would reduce the horizontal forces on the trees to effectively zero, making the tree a true column. But you can't do that with a rope.

Originally Posted by MDSH
We hang by friction. Friction is a dynamic process of transferring energy in the form of light, heat, sound, and motion. The bark of a tree goes frmm a stady state to a dynamic one once it is loaded with a hammock and tarp. Where does that friction energy dissipate? How is the stress distributed? The more widely it is distributed the less damage is likely done.
And to argue semantics, a tree loaded by a hammock is not any more dynamic than it was before. The forces applied on a tree by nature (mostly wind) are dynamic in that they change with time. (Note, gravity is pretty static.) Forces applied by a hammock are dynamic in that you get in and out of the hammock and sway while in the hammock. For most purposes, however, these forces are fairly static in that the fluctuating amount of the force is much smaller than the static part. Also, friction does indeed do two things: dissipate energy and transfer force. Energy that is dissipated through heat, light, and sound, is no longer usable and is lost. Force transferred via friction is still usable, like a spinning pulley powered by a belt. Dissipation only happens when there is relative motion between two surfaces (discounting internal friction from deformation of a material). Because the relative motion between the straps and the tree is close to zero, there is very little dissipation of energy going on. Instead, load is transferred to the bark, and then to the cambium, then the rest of the tree.

Now, the small fluctuations in the load and it's uneven distribution across the straps do cause fractures and deformations in the tree bark and dissipates some energy through friction (both external and internal), which is why the last huge paragraph is mostly semantics. My conclusions are similar to MDSH's, but I've just cleared up some terminology/mechanics of what is actually happening. Important semantics (to me anyway) but semantics nonetheless.

5. Wow, some deep stuff. A simple observation I would make is that one time, one tree, has different impact than if multiple times on one tree or on multiple trees. I hang about 300 nights a year. We walk as giants on the earth because of our impact. Not to exagerate to make a point, but bottled water is a good example. The average american uses 167 bottles a year, only one every other day, the collective impact is that one billion dollars worth of plastic goes into landfills in the US every year in the form of bottled water waste. I recognize that this is different in lots of ways.

Yet, if all 15,000 of us hung on trees w/o straps, I am guessing there would be some significant impact at some level. Just a thought, and HYOH.

6. I no longer hang from Aspens or Spruce since I have damaged* the bark with only one night of hanging. I weigh 190# and was using 1" tree straps.
damage- marks that cut thru the outer layer of bark

7. We can't think of our impact on tree bark and cambium as "just one night". How many trails have you seen that were ruts worn down to bedrock. One footfall might not have done visible damage.

8. Query: What effect would padding have on a 1" strap or cord? I've used a dish towel, wrapped around a tree limb before seating a cord. I suspect it could be worthwhile as a general practice e.

Browning>>>

9. Thanks for the responses. I've noticed the zing-it on my Superfly really digging into some trees once it's all staked down. It doesn't seem like anyone is really concerned. Anyone else addressed this problem?

10. doc, I am in the process of switching from zing-it to 3/4 inch nylon strapping on my tarps just for that reason.

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