Soren Eriksson's Pro-sight usage?

Old Greenhorn · October 06, 2019, 10:56:34 AM

So I mentioned in other posts that I took a GOL level 3 class on Friday. In that class I learned some new ways of estimating tree height and wedge lift required to overcome a given amount of back lean, as well as a bunch of other stuff. None of this stuff is new to me, but I did learn different techniques from what I had always done, so a very good day all around.
A new tool I was introduced to was this card developed by Soren Eriksson years ago to calculate where a tree top would land, segement height and wedge lift required. The class focused on these functions and I thought the tool was useful enough that I bought one from the instructor. However, it came with no instructions and the class only focused on the uses at hand. I see that there is also a slope calculator and probably a few other functions on it. A few of the guys in the class already had one handy in their pocket and I saw that they had a knotted string attached to the 3rd hole, presumably for use in this slope function.
I have searched and searched, but cannot find instructions for this gizmo. Neither can I even find a place to buy another one. Does anybody here have a resource they could direct me to? Mostly I like the card for figuring out where the top will land. I have always been pretty good at this using the 'perpendicular stick' method, but this is much faster and after testing, I found it is very accurate. Every tree I tried I hit within a foot. Still I would like to learn the other functions this tool provides.
If you are not sure what I am talking about, here is the first side of the card which provides a chart to determine how many segments in a given tree based on height and distance from the notch to the back of the tree (called Diam. on this chart)

On the second side you use the number of segments and the lean amount to determine what amount of lift (wedge height) will be required to get the tree to overcome the back lean.

What I am interested in learning is the other functions of this tool if anybody can help me out.

Tom

btulloh · October 06, 2019, 11:12:24 AM

I'm curious about this. Anxious to see replies.

By "perpendicular stick method", are you talking about when you hold a hand-to-nose length stick out at arms length and sight the top and bottom of the tree? Or some other method? Just curious.

Old Greenhorn · October 06, 2019, 11:13:58 AM

Quote from: btulloh on October 06, 2019, 11:12:24 AM
I'm curious about this. Anxious to see replies.

By "perpendicular stick method", are you talking about when you hold a hand-to-nose length stick out at arms length and sight the top and bottom of the tree? Or some other method? Just curious.

Exactly that. You have to be perpendicular to the line of fall, but it has always been very accurate for me.

John Mc · October 06, 2019, 11:18:09 AM

I've been through GOL levels 1-4 and their "Storm Damage Clean-up" class (twice on the SDC class). I have never seen or even heard of one of these gauges. Looks interesting, but not sure I'd carry it around with me. Interested in hearing about all of its functions.

Quote from: Old Greenhorn on October 06, 2019, 11:13:58 AM
Quote from: btulloh on October 06, 2019, 11:12:24 AM
I'm curious about this. Anxious to see replies.

By "perpendicular stick method", are you talking about when you hold a hand-to-nose length stick out at arms length and sight the top and bottom of the tree? Or some other method? Just curious.
Exactly that. You have to be perpendicular to the line of fall, but it has always been very accurate for me.

You can also be in the line of fall. When the top of the stick aligns with the top of the tree, you are standing where the top should reach.

lxskllr · October 06, 2019, 11:34:28 AM

I'd have to hold it in my hand and contemplate it. Hard to guess using pictures. Perhaps the cord is a plumb line that lines up with the angle marks as you tilt it? I used a pocket transit(now lost :^( ) once to determine tree heights at a quarry. Pull out 100'(makes the math easier), get the percent to the bottom of the tree, get the percent to the top, subtract them, move the decimal place, and you get the tree height. Perhaps the card does something like that, mixing up the math to get the result you want?

Old Greenhorn · October 06, 2019, 11:41:15 AM

Quote from: John Mc on October 06, 2019, 11:18:09 AM
Quote from: Old Greenhorn on October 06, 2019, 11:13:58 AMYou can also be in the line of fall. When the top of the stick aligns with the top of the tree, you are standing where the top should reach.

Well yes, and no John. Now I could very well be wrong here and I would rather not have to get out a trig book to do the math, but follow my logic and see if you can tell me where I am 'off'.
If I stand perpendicular to a tree and hold a stick in my hand sighting across the top of my hand where the notch would be and the top of the stick sights on the top of the tree, if I rote that stick 90° to the ground (on flat terrain) without changing the location of the top of my hand (still on the notch), then the top of the stick will now show me where the top of the tree will land. This has always worked well for me since I was just a kid.
Now if I face the tree, standing where I think is will fall the height of the stick becomes very important. If I stand too close, I could just use a longer stick to cover the top of the tree, further away I could use a shorter stick. Either way I could likely be wrong. SO there has to be some calculation involved to get the right stick height. Am I not correct here? If not, let's talk it through.
If you look at the second photo in my above post, you will see two screws sticking out. These are actually sight pins, like on a bow site. You place the square notch on the card just over your dominant eye then position your self so that the lower pin is at your notch on the stump and the upper pine sits on the top of the tree. When you hit this condition, you are standing where the top of the tree will land. If needed, you could measure from here back to the stump to get the actual height. You have to compensate for forward or backward lean and upward or downward slope from where you stand but it gets you mighty close from the field testing I did with actual falling to confirm the estimates. I seemed to routinely estimate about 1-2' longer then where the top actually fell. I found this quite acceptable.

Skeans1 · October 06, 2019, 11:42:14 AM

I've got a card like that somewhere for doing poles it figures out the scale before cutting it's not perfect but get you close.

John Mc · October 06, 2019, 12:15:14 PM

Quote from: Old Greenhorn on October 06, 2019, 11:41:15 AMWell yes, and no John. Now I could very well be wrong here and I would rather not have to get out a trig book to do the math, but follow my logic and see if you can tell me where I am 'off'.
...
Now if I face the tree, standing where I think is will fall the height of the stick becomes very important. If I stand too close, I could just use a longer stick to cover the top of the tree, further away I could use a shorter stick. Either way I could likely be wrong. SO there has to be some calculation involved to get the right stick height. Am I not correct here? If not, let's talk it through.

No calculation necessary, but yes, the length of the stick is important:

If the length of the stick above your hand is the same length as the distance from your outstretched hand to your eye (just flip the stick back toward you to measure), this method works. Hold the stick up at 90˚ to your outstretched arm. Walk to the point where you can just see where the notch in the trunk will be above your fist, and the top of the stick aligns with the top of the tree. (If the tree is taller, back up. If the stick is taller, walk toward the tree). When everything lines up, you are standing where the top of the tree will land. The technique does assume level ground (or nearly so). But it does work.

btulloh · October 06, 2019, 01:08:03 PM

It's got to be some sighting thing with the cutout, but I can't quite figure it out.

I'd probably leave the card back at the shop anyway, either on purpose or by accident. I always found the stick method to be very accurate, and sticks are where you are.

The ax works too, but can leave a nasty wound depending on which end you use to set the length. :D

Pine Ridge · October 06, 2019, 02:58:39 PM

The instructor had a sight card in our class in 2013. He had a string hooked to the sight card with a scrench tied to the end to estimate how many feet of tree lean, other than that i don't remember much. Old greenhorn i will pm you the name and number of a guy who can explain all about the sight card . I have and use a Biltmore stick sometimes to get an idea of how many board feet in standing timber and such, but i never did buy one of the cards.

Gary_C · October 06, 2019, 05:58:34 PM

Quote from: Old Greenhorn on October 06, 2019, 11:41:15 AM

If I stand perpendicular to a tree and hold a stick in my hand

You kind of lost me there.

Old Greenhorn · October 06, 2019, 07:13:38 PM

Quote from: Gary_C on October 06, 2019, 05:58:34 PM
Quote from: Old Greenhorn on October 06, 2019, 11:41:15 AM

If I stand perpendicular to a tree and hold a stick in my hand
You kind of lost me there.

Gary, it's the quickest simple way I know of the predict where the top will hit. Stand perpendicular to the direction of fall. Hold a stick at arms length and set it so that the top of the stick is sight even with the top of the tree. Without moving you had rote you wrist until the stick is parallel to the ground, now the top of the stick is where the top of the tree will land.
@Pine Ridge, yes, got your PM, thanks. I should really call my instructor first, I just don't like bothering him, he is a busy guy. You make be right about the lean slope thing. I will have to lok at it again. There is a complex way to figure height using positive and negative sope and I thought that was what it was for, but now I am thinking it might be slope for back lean. I have to go get it back out and parse it out from that point of view. Good idea.
@btulloh Its hard to explain the use anymore than I already have above.
@John Mc yes I know this method, but you not mentioned stick length in your first description. I am clear on that now. Yes, that is the exct same function as the card in this case.

lxskllr · October 06, 2019, 07:38:14 PM

I'm about 90% sure the scale calculates lean with a plumb line attached to the hole. You look through the window and tilt card til the tree is inline with the window, and the plumb line will be on one of the angle scales. The card is upside down in the picture.

edit:
I guess you could use it as shown, and follow the angle line down to the string. Not sure which would be easier. Could try it in the field and see.

John Mc · October 06, 2019, 07:47:05 PM

Quote from: Old Greenhorn on October 06, 2019, 07:13:38 PMGary, it's the quickest simple way I know of the predict where the top will hit. Stand perpendicular to the direction of fall. Hold a stick at arms length and set it so that the top of the stick is sight even with the top of the tree. Without moving you had rote you wrist until the stick is parallel to the ground, now the top of the stick is where the top of the tree will land.
...
@btulloh Its hard to explain the use anymore than I already have above.

A clarification: Hold stick vertically so the top of stick is sighted even with top of tree, and adjust grip so the spot where you will notch the tree is just above the hand holding the stick. (That is, the top of your gripping hand is sighted on the base of the tree while at the same time the top of the stick is sighted on the top of the tree.) Now rotate your wrist sideways in the direction the tree will fall till the stick is parallel to the ground. Keep the grip end sighted on the base of the tree. The top end will now be sighted on the spot where the top of the tree will reach.

Did that help?

John Mc · October 06, 2019, 07:50:34 PM

Quote from: Old Greenhorn on October 06, 2019, 07:13:38 PM@John Mc yes I know this method, but you not mentioned stick length in your first description. I am clear on that now. Yes, that is the exct same function as the card in this case.

Yeah, I was not clear in my original post. I figured you would recognize the technique with an abbreviated description, but I see now that it was far too abbreviated.

Old Greenhorn · October 06, 2019, 07:57:13 PM

No problem at all. As soon as you mentioned matching the stick length to your arm length I realized where you were going. I had forgotten about this method because I always stand perp. to the tree and the stick length does not matter because you are just swinging an arc to see where the top will land. With you method (same as the card that started this, you can also measure the height by measuring from where you stand to the base of the tree.
With the simple method I can determine if I need to move the truck so I don't hit it, with your method you can tell exactly how much you will hit the truck by. ;D ;D :D

btulloh · October 06, 2019, 08:02:23 PM

@John Mc
@Old Greenhorn

:D :D :D :D :D :D :D :D

This reminds me of a line from "Cool Hand Luke".

Before this goes off the rail any further . . .

Thanks for the explanation though, John MC. I've been using the stick method for a long time with success. I plan to keep using it.

I must have said something in my previous post that confused things. I am waiting to hear an explanation of the Soren Eriksson Sight-gauge, which I believe is the original question.

A casual search turned up nothing about the Soren Eriksson Sight-gauge that would explain its use, which I think parallels Old Greenhorns results. I did find a similar contraption on the Treestuff.com website, but not the same and also not explained.

Anyway, thanks for all the concern. Hopefully someone will be able to explain the Soren Eriksson Sight-gauge.

btulloh · October 06, 2019, 08:05:51 PM

I usually put a Faberge Egg three inches from where the top of the tree will land just to see how accurate I am with the stick method. I usually borrow someones hat to land the tree on, so I don't hurt MY hat. :D

At this point it's important to note: I have NEVER broken a Faberge Egg, so the stick method is working well.

Old Greenhorn · October 06, 2019, 08:24:07 PM

@btulloh In my first post I did explain the main functions of this tool very briefly, that is segment calculations to determine how much lift is required to overcome back lean. Also the sighting function to determine where the top of the tree will land, which I explained in a later post. This is all understood by me and I find it useful. It was the other apparent functions of this tool I was asking about. Apparently there is a slope function and I see another scale along a bottom edge that I do not yet understand.
Calculating tree height from slope is a well known process, just not very well understood by me and I have read the procedure dozens of time. There is way too much math. You can read of it HERE to your heart's content. ;D As I recall now @nybhh uses a clineometer to do his height calculations, I should bring this by on my next visit and see if he can clue me in. He is really good with that math stuff. ;D

lxskllr · October 06, 2019, 08:33:38 PM

Quote from: Old Greenhorn on October 06, 2019, 08:24:07 PMHERE

This is what I was talking about with getting tree heights...

Using 100' simplifies it.

edit:
$10 says the bottom scale tells you how much lean you have when sighted at 50'. Line the bottom of the tree with one mark, and the top of the tree with another mark. Each tick away from the origin=1' of lean