TR Anchor with only 1 tree

brianjames wrote:Is there a general consensus on the minimum diameter of a tree?

Seriously, I heard somewhere that 6 inches dia. for a hardwood, 8 inches for a pine or hemlock, provided of course that the tree is healthy.

michael s... wrote: I was not aware there was only one book on climbing anchors. Thank you for your helpful feedback. The pointlessness of my original suggestion has been made clear to me as a result.

ok, a book. I remember being in the OP's shoes. I had read John Long's book on the anchors cover to cover maybe 2-3 times. Also, numerous websites on SRENE, EARNEST whatever you call it anchors. Still it was not clear back then if a single big tree or a boulder (provided being solid) were adequate, so I had spent hours looking for that second and sometimes third redundancy piece, building over-engineered anchors.

Right or wrong, in Red Rocks I regularly see people using trees that are only 6" in diameter. I think pitch two of Cat in the Hat is a single tree rappel.

i'm all for redundancy n stuff
but theres only 1 belay carabiner....(unless you run 2 through your ATC and belay loop)
and only 1 brake hand.... (assuming no gri gri)
and only 1 rope.....(assuming no twins/doubles...and yes, i know single ropes are engineered to be strong enough)

make things as strong and safe as reasonable, but know that rarely are things truly fully redundant
only as safe as your weakest link :)

Marty C wrote:There was a paper presented at the ITRS (International Tech Rescue Symposium) in 2010 by Rick Weber - "How to Determine Tree Strength and Build Tree Anchors". It was concerned primarily with rescue operations and such, but they did have some test results for tree strength that was interesting (bottom line, small trees are surprising strong) The ITRS website is ITRSonline.org

Found the paper efclimbers.net/wp-content/u… and it confirms that 6 inches (15 cm)is safe. "Trees of all species above 15 cm in diameter showed no signs of uprooting when the BCDTM
load was applied via an anchor to the lower portion of the trunk".

No offense to the op, but this is where some common sense comes in. Formulas and standards are helpful, but in all cases they are to be taken with a grain of salt. The fundamental thing is to understand what you are doing and why. You could have a bomb anchor and then have your TR seesaw over a sharp ledge. Being able to see your master point is an important aspect of the TR setup, especially if you will be managing from the ground. And and you would not want to sketch down off a crazy ledge to set up the master point, no matter how sketch or bomb the anchor is.

In the case of a redundant tree...consider what would happen if the tree failed...a freegin tree would A) come crashing down on the climb smash the climbers and B) fall on 1/2 or 2/3 of your anchor, destroying it and then continuing down on to the climbers. In both cases, your gonna die. As has been said, tree failure can't really be considered a legitimate concern. The health of the tree is taken into account, and if it passes muster for a single anchor, than it passes muster. Same as with a single rope, single belay device etc.

OP, your question about redundancy is well founded. My redundant advice and it's irony is noted. I don't think anyone told you about 1" tubular webbing but it's cheap and easy to use for tree anchors. A water knot is all you need. Safe and happy climbing

whenever I tie off a tree on the edge of a cliff I like to give it a solid "push" test first. all that entails is a running start and a good ole' college try at knocking it down. repeat at least 3 times.

^ as ben said, use something padded (old sweatshirt or something) to pad the tree. other than that, secure a loop of webbing before hand with a water knot. Throw that SOB round the tree, and make a master point with an overhand. If the tree was sitting on an overhang, reevaluate. but if its in solid ground, yer good ta go! One static line should be fine, just do the same thing i described with the webbing so you have a "redundant" lashing to the big ass tree.

Lots of good advice here so far! The thought process that comes to mind for me when I come up to a tree that I would like to acnhor to is as follows:

• Is the tree alive?
• is it wider than my neck in diameter? (folks may dissagree with me on this)
• Does it seem to have a good root system?

I tend to avoid trees that have obviously shallow roots, like on a thin patch of dirt on a granite slab. I also try to avoid dead, skinny trees.

Remember... safety is no accident!

kday wrote:There's a route I found that I'd like to climb but there's not much in terms of building an anchor. There's 1 giant tree near the edge (maybe 3 feet in diameter and only 2 feet from the edge) that would be great for the anchor, however there's nothing else. I know the key is redundancy so I was curious if just using this one tree would be safe. I'm confident the tree is going nowhere :) Also, since there's only one tree what's the recommended anchor to build on it? Could I rely on 1 static line for the anchor? I don't have anything long enough as far as webbing/cordellete to wrap around the tree.

Alternative is to fiddle with some tiny nut in a useless crack to call it a 'backup'. Not worth it. I go for the totally immovable object, such as this massive 3 ft thick tree, and just double up my rope or slings on it. Redundancy done. Tree or huge massive boulder isn't going anywhere. If for some unfounded reason the tree or boulder started to move, you would notice that and be able to lower off FAST well before this huge anchor tree came over the edge and failed 100%. I live with the immovable object for many a toprope set up; just use 2 identical length slings so force is equally on both of them, with double carabiners on them for the rope. My success rate on this since the mid 70's has been 100%. Just choose the right anchor and proper set up. We all lead climb and sport fall endless times on just ONE 3/8ths inch bolt day after day, so why won't a 3 ft. tree suffice for a top rope anchor? Think about it.

Hey guys. Thanks for all the great info. It certainly helped. I should have used a little more common sense before posting the question. I already knew the tree was bomber but still wasn't sure what the best practice was. I did learn some new variations of setting up the anchor so thank you for that. I'm going to re-examine the area and see what's best.

This was also my first post so I wasn't sure what to except but after spending quite a bit of time reading other forum posts, I realize that my question did seem extremely amateur. I should have done some more digging first.

Some comments on tree anchors...

A single tree is usually fine as long as you inspect it and it's 6 inches or greater in diameter. An inspection should consider everything - is it rotten, is it placed in solid ground, good root system.

At that point - as someone else said - you want to follow redundant patterns in other parts of the system. like a cordalette around the tree that's already looped (so you get double strands. Think about a master point.

FINALLY, keep in mind that the SHELF on an anchor like this is around all the strands to the right or the left of the master point. If you consider the shelf on a normal redundant anchor, you'll end up clipping through a single strand which really isn't redundant.

Natural anchors are fine though - just learn to do it right.

books.google.com/books?id=l…

David Gibbs wrote:Generally speaking, a big living tree is absolutely bomber. The amount of force you can put on it, wrapped around near the base, is trivial compared to the amount of force a bit of wind through the upper branches will exert.

Exactly. A live tree 6" or more in diameter will not move when you fall on it. Even a modest spring breeze puts an order of magnitude more force on that tree's root system than a Holstein taking a whipper. If it's green and standing, you are not going to pull it over.

I use a 4" wide piece of webbing when setting a TR anchor to a tree, in order to protect the bark and not do damage that will allow insects to get in. (It's easier to carry than a bunch of carpet, and carpet doesn't always stay where I put it.) It's actually a load tie-down strap that truckers use, rated at 54,000 lb (240 kN), and available pretty cheap at any truck stop. Plus it's very abrasion-resistant; I can run it right over the edge of the cliff. Even allowing for the knot and the cliff edge, it's about 5x the strength of my rope. That and the tree I take for granted. Then I worry about making the rest of the rig redundant.

Lee Green wrote: Exactly. A live tree 6" or more in diameter will not move when you fall on it. Even a modest spring breeze puts an order of magnitude more force on that tree's root system than a Holstein taking a whipper. If it's green and standing, you are not going to pull it over. I use a 4" wide piece of webbing when setting a TR anchor to a tree, in order to protect the bark and not do damage that will allow insects to get in. (It's easier to carry than a bunch of carpet, and carpet doesn't always stay where I put it.) It's actually a load tie-down strap that truckers use, rated at 54,000 lb (240 kN), and available pretty cheap at any truck stop. Plus it's very abrasion-resistant; I can run it right over the edge of the cliff. Even allowing for the knot and the cliff edge, it's about 5x the strength of my rope. That and the tree I take for granted. Then I worry about making the rest of the rig redundant.

I like it, especially the part about your awareness of the damage done to trees in busy places. Here in CT all the crusty old topropers believe the trees were Gods gift to toproping.

I've thought about using tow/lifting straps in place of webbing but really wrapping any 1 inch tubular webbing enough times around the tree keeps it from rubbing the bark.

;)

if you hit it with a car what would happen? Would car or tree win? That's how I judge a single tree anchor... and we're pros here in CT. You should see what our trees look like above our cliffs. #CTfuckedandMangledtrees