standard protocol for tie in points

Maui Palm & Tree Care

Maui Palm & Tree Care

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Pukalani, Hawaii
what are the protocols for tie in points on tree's. im getting a bit nervous on what i was taught. my mentor taught me that anything over 2 inches diameter will support your weight but i normally dont go that small. i go for something bigger like a 4-6 in some cases. what is the minimum safe diameter for tie in points? i really would like to touch upon this subject since our lives are on the lines(pun intended).
 
I was told that the branch (now depending on species of tree) should be larger than your wrist. That's what I was taught in school as a general idea
 
my thoughts:

if you don't believe it will support your weight, don't tie in there.

tying in around the trunk and over a limb is preferable to tying in over a limb, generally.

If the limbs are big and the trunk huge, and tying in over a limb is the only real option, two limbs are better than one.

your tie-in should be high enough to allow you to access all work positions, preferably with a 45 degree angle or less.

Avoid 90 degree angles over limbs. Make sure your rope runs smoothly and freely, and doesn't lodge in a big blob of pitch, or tangle in twigs or stubs.

Sometimes the best tie-in is a double crotch.

Since trees differ regionally, my advice may not hold true in other peoples experience.
 
Big thing is to be tight to the attachment crotch. Don't forget to test the TIP from the ground, if in doubt have two people hang on it and bounce. Try to break it. Also know the species characteristics, like willows can't be trusted.
PS, try and get video of two people bouncing on the rope.
 
I bounce test most TIPs, and with two people if possible. If it holds, but is not optimally close to the union, I will gently climb to adjust the TIP, then set to work.

If I am climbing SRT, I will consider choking the TIP if its already isolated, to avoid the doubling effect of a rope heading down to the base of the tree.

Avoid a rule, such as wrist size, 2", etc. Take those as guidelines in the wager where a fall is the consequence of losing.

Look for defects, such a highly included crotch, where you are over one half.

Use binoculars if you want more info.

Be sure you are not on a dead limb (while this may go without saying, you could be over a 5" limb with a perfect shot at the union, but not notice a lack of foliage/ buds. Binoculars will reveal buds, oftentimes).
 
Even if you don't climb SRT, you can always initially tie a running bowline to the base of the tree with the running end of the line, then bounce test the working end - 2x your weight on the TIP, if my physics are right, and you can avoid the socially awkward 2 person bounce test.

Also, I read this in Ed Gilman's <u>Illustrated Guide to Pruning</u> the other day - It's a little bit of a long quote, but I think it's pretty relevant here and dispels a myth that I was told about angle of attachment, which is the part I put in bold type. See below:

"Fast-growing branches on young trees frequently grow upright, forming a narrow angle in relation to the trunk. Bark can become pinched or included in the crotch. This phenomenom has led to the misconception that the branch angle is related to the strength of attachment, which is untrue. For example, a large-diameter branch growing at a wide angle can be as poorly attached to the trunk as a similarly sized branch with a narrow crotch angle. It is the presence of included bark that indicates a poor attachment. Although included bark is most common on upright branches growing at a narrow angle in relation to the trunk, on some trees it develops in the union of branches growing at wider angles." (Gilman pg. 32)
 
Good point for double loading the DdRT system, especially if you are using a friction saver, where less force is lost to friction, and more of a full doubling effect occurs.
 
Sean,

Can you explain a little more what you mean about how the FS affects the loading? I use a Buckhingham FS (love it!) and was unaware that it changed the load.

thanks!
 
I believe the following to be true. Probably will be missing some important caveats, though.



Assuming that we are talking somewhat theoretically in a physics context here.

The doubling force effect on the rigging point when using a low friction block (maybe, maybe 10% energy loss to friction, or for simplicity assume the block is really nice and new and fancy and has negligible friction) comes from an input force on once side of the block, ex. 100 pounds, has to be counteracted by 100 pounds of resistance, therefore the block experiences 200 pounds of force.


If you are losing some of the energy of the 100 pounds of weight (weight is the force from gravity) to friction over the crotch, you are not getting the exact same output of the doubling effect on the crotch. Let's say for example, roughly 1/4 of force is lost to friction, so the other resistance force would be about 75 pounds. Your TIP is now experiencing 175 pounds of force rather than 200.


The FS is smoother so less energy is lost to friction. If you are using a pulley, even more so. You will get less friction loss of force (and the equal and opposite force of the resistance of the tied off rope at the base). 100 pounds will have, maybe 90 pounds of resistance force, so 190 pounds of net force at the TIP.


I'm around 200 pounds when geared up, with a climbing saw. Ben is around 200 pounds. 400 pounds of input will quadruple the difference in force between a low and high friction system. Maybe we are in reality speaking of a difference of 100 pounds of force on the TIP, especially if we bounce a bit.


In most cases, this difference is not going to break the camel's back, but considering it might be worthwhile. This might be more important when setting a floating anchor block for rigging without actually being up at the rigging point. As an example rigging the top of one tree into an adjacent tree, or using a drift line system where you gain horizontal distance as you change the percentage of load from one tree to the other (in Art and Science of Practical Rigging).


Hope this makes sense. I have to bolt out to an appointment, so haven't proofread this yet, so sorry if it run-on, or typo'd.
 
It depend in the type of tree, considering that the properties of the wood changes with the type of tree. An inspection of the tree is also needed. Decays or cracks must be taken into account. Also if you are using SRT, it doubles the weight on the TIP. Im sure there are more things to consider. These are just a couple I could think of
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Sean - thanks for taking the time to explain - that's great. May take a little bit for all the math and physics to sink in, but I'll keep running through it in my head...
 
Joshua-

This extra force from a FS is only when you are tying off to the base to pull test, where the FS acts as the low-friction pulley, as compared to a typical SRT redirection up top over a natural crotch. (I say typical, though there is nothing wrong with using a false crotch friction saver, or cambium saver leather tube/ synthetic tube with SRT.)

In its normal use, its the normal force. I would imagine it could reduce the force on the TIP in a small way, as the rope will be less likely to have pitch on it, which can cause a hitch to ride herky-jerky, rather than smooth. Probably insignificant.
 
That is an excellent point Sean. Though it's off topic, and I'm sorry for that, we used retrievable false crotches a lot for rigging and I've never really thought about the forces being inflicted upon the system. Just the block is seeing two times the load, but the crotch that block is set through is likely seeing close to 4 times the load.

Back on topic, as several people have said, there is no set standard or guideline. If you're inspecting a tree and are unsure about the size of a selected tip, don't use it until you can climb up and inspect it thoroughly. If nothing else, do a bounce test before you begin you ascent. I know of two people right off the top of my head that have had tips break out and violently disrupt their career.
 
as has been said knowing your species of tree is key--will tie in much higher on most oaks than on tulip poplars. also, know your attachments, if the highest feasible tie in point that i like branches off awkwardly further down in the canopy than i am going to be somewhat wary of it. as far as srt goes, the 2x's rule is great to keep in the back of your mind as far as safety goes, but if you are passing through multiple crotches than you aren't really putting 2x's the force on the topmost point. i have tied in to some kind of crazy things while using srt because i was through probably 10 to 15 different crothches. you are also pulling on those limbs in a different way than you would be with a direct pull with Ddrt.
 
[ QUOTE ]
as far as srt goes, the 2x's rule is great to keep in the back of your mind as far as safety goes, but if you are passing through multiple crotches than you aren't really putting 2x's the force on the topmost point. i have tied in to some kind of crazy things while using srt because i was through probably 10 to 15 different crothches. you are also pulling on those limbs in a different way than you would be with a direct pull with Ddrt.

[/ QUOTE ]

This is true about loading the crotches in different ways, and the subsequent force down those branches/ leaders.



If the climber is pulling down with 200 pounds of body weight/ gear, and the rope is not moving at the highest crotch (say it doesn't contact any crotches on the climbing side), how much force does it take on the opposite side of the crotch to keep the rope from moving?

Still 400 pounds, minus the amount lost to friction over the highest crotch, I would think.
 
It depends on species and condition I usually would say if 4 or 6" is safer than 2" if it will work just as well for you. But on that note I'm also a fan of using friction savers.

On Spruce, etc that are straight up and down it's safer on 2" TIP because there's little to no side loading. But some hardwoods, etc. 2" is ok just know what you're going to have do from the TIP and do what you feel is safe.

But when it's easy enough tie in big and use a friction saver
 
4 inch and if possible tie in so if the limb snaps you will be on the main spar and slide to the next branch union..

be safe..if possible use a false crotch it will reduce friction on the limb union and add to your safety plus it is easier to climb..less friction.
 
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