Murphy's Step Cut

[Tucker943]

I have silver maples in my area that would make most mens eyes cross......

 

[mistahbenn]

I don't recall ever having used a step cut with a "thicker than necessary" hinge.. the two have different uses and do not combine well... if you took the time to watch a few videos, you might get a different impression.. I use what is needed in any given situation... with a few extra tricks in the bag..

Murph, have you got a wireless keyboard? You're full stop is stuck, maybe change the batteries?

 

[Al Smith]

I have silver maples in my area that would make most mens eyes cross......

They get big just about everywhere .Problem is they get hollow about everywhere too given enough time .

Suppossedly silver maple is a native Ohio tree yet in my 65 years on this earth I've never seen a one of them growing in the woods .Those are all sugar maples .

 

[Tucker943]

They don't grow in the woods here but do line the wooded river banks.

 

[murphy4trees]

They get big just about everywhere .Problem is they get hollow about everywhere too given enough time .

Suppossedly silver maple is a native Ohio tree yet in my 65 years on this earth I've never seen a one of them growing in the woods .Those are all sugar maples .

Mostly they get hollow from improper pruning cuts.. very prone to unstoppable decay once the BPZ has been violated...

 

[Al Smith]

I have no idea what a BPZ is but they do rot from the inside out .To tell the truth before the EAB thing the silver maple probabley provided the majority of the tree trimmers incomes locally .

The fattest one I ever encountered I have a picture of in 1909-10 and about 10 years ago when it was felled it was 54 inchs at breast height .I didn't trip up but I bucked it .That's the one I cut through a nest of hybernating bats in Feb.The thing was solid though .About 40-45 feet of big fat trunk with a void in the top full of bats .At one time probabley the wind blew the top out which happens often .

 

[murphy4trees]

I have no idea what a BPZ is but they do rot from the inside out.

Not sure what you guys are talking about... the monster fibers in the center of this hinge tell a clear tale.. extreme holding power of both fat hinge and center fibers.. (just happen to run across the pic today)..

ps al.. bpz is branch protection zone (don't mess with mother nature)

 

[Al Smith]

Well yes usually a maple if cut green and with an open enough face cut will hold clear to the ground .Even a bone dead one will hold long enough it won't flip flop on the way down before it breaks over .Now those old hundred year old hollow ones won't but they usually go where you aim them .Then the squirrels and raccoons and other stow aways make the great escape .

 

[woodworkingboy]

People sometimes seem to forget that trees are actually made from wood! I know a number of my customers do. :roll: Scientists have pretty much determined how wood with species and moisture content variations are going to respond to different stresses up to the point of breaking. A six inch long stick is much the same as a seventy foot tree. If you start complicating the situations with compound stresses, rot or kerfs or steps cut so that breakage gets initiated from an assortment of human induced starting points, the scenario may differ from what is commonly done with the more simplistic set ups in the laboratory, but the fundamentals in terms of how wood responds are going to be the same. If you have a vice you can make your own laboratory. Not saying that a guy working in the woods with his differing experience can't tell you more than a scientist about how to expect something to respond, but at least scientists are able to come to agreed upon conclusions for the most part. Lots of useful information in charts. Tests have to be verifiable.

 

[Jed]

Totally agree Brian: Tests have to be verifiable. Which brings me to one of the most frustrating elements of our trade. We're basically never in the same situation twice. E.g. I was doing some horribly nasty dead, dead, dead (no bark left at all) Elm removals up in Snoqualmie, WA--a much different environment from Santa Fe, NM where I had had most of my Nasty Dead Elm experience. I told the estimator that I was scared, and that I wanted the bucket. He laughed and called me a wuss. I called him some stuff cause he's never removed anything bigger than an apple tree. Long story short: I climbed up those pigs (way too much underbrush for a throw-line) to set pull-lines, and to take some back-weight out, with my knees knocking the whole time, and everything went where it was supposed to because apparently, God still loves alcoholic idiots. But I'm telling you...... you can never absolutely count on the same rot patterns, wind-check patterns, dry-check patterns, and etc. twice.

And Murph: You know I love you, but why would you have sap-wood cuts on that pig?

 

[murphy4trees]

Exactly the point I've been trying to make.

Any comments from you (Stig) or Tucker on the above pic? Those center fibers aren't toothpicks.. huge holding power....

I don't remember the tree Jed.. Looks like a Norway maple..not sure why I nipped that corner, but it seemed like a good idea at the time...

 

[rbtree]

I'd have to search my photo archives, but I have images of two massive ones in Wa state.

One is pushing 7 feet dbh with a crown spread of 120 feet at its widest. In good health, but had a large lead removed so it wasn't as wide on that side. ( I think it broke)


Another, before it was side pruned aggressively, was well over 100 feet wide, and (I think) close to 6 feet dbh..a stupendous and healthy tree.

 

[stig]

I read the picture different, Murphy.

That you get huge fiber pullout in the middle, doen't tell me that the fibers in that area are more pliable/stronger than near the sapwood. It tells me that you've ruined a log by not having enough stumpshot.
Not a consideration in your work, but certainly in mine.

Trees are different enough, even within one species, that a picture isn't conclusive evidence of anything but that this particular tree hinged well in the middle.
We are between logging seasons right now, or I would easily be able to collect pictures showing the opposite.

I see you using sapwood cuts. if the sapwood was weaker, they wood have no purpose, or?

I consistently bore the middle out of my hinges, because I find that the bendable sapwood is more reliable and having two separate blocks instead of one hinge gives me more control, particularly on sideleaners.

 

[Tucker943]

I have nothing to offer. Its a picture of a big hinge. Cool.

 

[flushcut]

One is pushing 7 feet dbh with a crown spread of 120 feet at its widest. In good health, but had a large lead removed so it wasn't as wide on that side.

That is about the size of an esti I ran for one a few years ago. I put 10g's on it and the tree is still standing. It is the biggest silver I have ever seen, HUGE!

 

[woodworkingboy]

Stig gives a vague response, and I believe it is also the most authoritative one. Within a given species, it is known that there is a direct correlation between elasticity/bending strength and wood density. Denser wood has stronger physical properties, as in bending a greater amount before fracturing The most dense woods don't necessarily make the best wood to bend, talking about within each species. An extremely dense wood like Ebony is brittle. Some trees exhibit increasing higher density from the pith outward, some species it is the opposite, and with others, there can be no change in density through the growth rings. Some trees will have a higher density near the pith, then decreasing density for a number of rings, and as you go out to the oldest wood the density increases again. Slower growth is often associated with higher densities, but it can be the opposite as well in other species. Densities can differ between the same species of naturally growing trees and those that have been planted. Environmental factors can affect densities, that is the way that people can use growth rings to determine what weather patterns were like before earlier times were recorded. It's all pretty complex and varying, and moisture content adds an element as well. 100% green wood doesn't generally bend as well without structural damage as wood that has lost a certain percentage of it's water. Without knowing species specifics, and also maybe some other factors that you would be hard pressed to determine at all, you can't draw such clear generalizations about where the best hinge wood is located.

Via a number of studies that I read, sap wood seems to be the least structurally sound wood, though right next to it can be the strongest. I have never found sap wood to steam bend worth beans, breakage is predictable, say on established good bending woods like Locust or Oak.

 

[murphy4trees]

I consistently bore the middle out of my hinges, because I find that the bendable sapwood is more reliable and having two separate blocks instead of one hinge gives me more control, particularly on sideleaners.

Perhaps one important consideration would be to include "when falling with wedges". I think that is the crucial difference here Stig, especially on side leaners, where the fibers on the tension side do the most to fight the lean. Makes sense eh? That's a much different scenario than pulling with a high pull line, set in the top of the tree, with thousands of pounds of force, ready at the wave of an arm. That would be like a vacation for you. While "my methods" are pragmatically superior, offering a lot more control and flexibility, yours clearly require more skill. Maybe that's why we have tended to but heads in the past. You look at me and think, I've got 10x the skill. While I, with my limited skill set, regularly drop trees that would make most arborists soil their pants, and most loggers tuck tail, thinking these guys have no clue what's possible when you combine good cutting technique with that kind of force.

With wedges you do not have the option of leaving a fat hinge, so on side leaners you need to leave fibers in the hinge that the give the most fight of the lean. In that scenario, gutting the hinge makes a lot of sense. Also as you mention fiber strengths are going to be different, even within one species. My theory is that a leaning tree develops especially strong fibers on the tension side. same thing with horizontal limbs, the fibers on the top and bottom are going to have different properties. So while your methods and skills are excellent, you might want to reconsider your conclusions about the nature of sapwood. Its not that sapwood is more benadable/reliable, its that the fibers on the tension side of the stump have grown to fight the lean and are in the most leverages position to fight the lean, which is just what you need.

I learned something from this conversation and appreciate your input..

 

[stig]

Interesting point, which I hadn't considered.
Tension wood versus compression wood, certainly makes a big difference in both density and strength.
Any woodtruner who has accidentally made a bowl and included both kinds, will have noticed that it has warped completrely when drying out.

 

[woodworkingboy]

Studies of variations in tissue structures in trees and the mechanical properties that result, would seem to conflict with your theory, Daniel. You are right in thinking that reaction wood (compression or tension) structure is different from normal wood that is in greater equilibrium, and that the stress induced growth patterns are generally largest towards the outside of the tree, but while compression wood is found to be denser wood, sometimes much greater so in sap wood, tension wood is found to have thinner cell walls and other characteristics that make it less dense, and consequently mechanically weaker than normal wood a relatively equal distance from the pith of the tree.

 

[Tucker943]

What Jay said. Just look at the growth rings on leaners. The tension side rings are wider.

 

[murphy4trees]

Studies of variations in tissue structures in trees and the mechanical properties that result, would seem to conflict with your theory, Daniel. You are right in thinking that reaction wood (compression or tension) structure is different from normal wood that is in greater equilibrium, and that the stress induced growth patterns are generally largest towards the outside of the tree, but while compression wood is found to be denser wood, sometimes much greater so in sap wood, tension wood is found to have thinner cell walls and other characteristics that make it less dense, and consequently mechanically weaker than normal wood a relatively equal distance from the pith of the tree.

It was just a theory Jay.. one that makes sense, but may prove to be wrong.. your explanation sounds a bit simplistic.though. I thought there were different types of wood strength.., strong in tension vs strong in compression. also thought that conifers tended to put on more growth in compression wood in response to side lean, while hard woods put on more growth in tension wood.. read that some where,,

 

[murphy4trees]

heard somewhere that all good hinging trees were strong in tension.. going to bed...

 

[Bixler]

Perhaps one important consideration would be to include "when falling with wedges". I think that is the crucial difference here Stig, especially on side leaners, where the fibers on the tension side do the most to fight the lean. Makes sense eh? That's a much different scenario than pulling with a high pull line, set in the top of the tree, with thousands of pounds of force, ready at the wave of an arm. That would be like a vacation for you. While "my methods" are pragmatically superior, offering a lot more control and flexibility, yours clearly require more skill. Maybe that's why we have tended to but heads in the past. You look at me and think, I've got 10x the skill. While I, with my limited skill set, regularly drop trees that would make most arborists soil their pants, and most loggers tuck tail, thinking these guys have no clue what's possible when you combine good cutting technique with that kind of force.

With wedges you do not have the option of leaving a fat hinge, so on side leaners you need to leave fibers in the hinge that the give the most fight of the lean. In that scenario, gutting the hinge makes a lot of sense. Also as you mention fiber strengths are going to be different, even within one species. My theory is that a leaning tree develops especially strong fibers on the tension side. same thing with horizontal limbs, the fibers on the top and bottom are going to have different properties. So while your methods and skills are excellent, you might want to reconsider your conclusions about the nature of sapwood. Its not that sapwood is more benadable/reliable, its that the fibers on the tension side of the stump have grown to fight the lean and are in the most leverages position to fight the lean, which is just what you need.

I learned something from this conversation and appreciate your input..

 

[woodworkingboy]

Yes, I know it was just a theory, and in the same spirit for discussion purposes, I was just saying that the empirical evidence by way of testing in the laboratory doesn't support it. Dan, you can correct me if I am wrong, but although there is a pretty good list of qualities that comprise what are considered the mechanical properties, strong in tension or compression don't seem to be listed as inherent qualities in themselves, those terms more so only as parts of the anatomy of a tree, not criterions for concluding strength. How tension or compression wood behaves when stresses are put on them, seems to be generally listed within the context of properties like elasticity or degree of bending before breaking, shear or tensile strength parallel to the grain....all kinds of tests and all minds of properties that have been devised. Scientists get into it, they even have something called the speed of sound and how ii is effected by density and elasticity and grain direction. If we ever get around to debating the sound that a tree makes when falling, how close to real time it is.....:roll:

I was looking at some references and one source said that in some cases that tension wood can be of a higher density and strength than normal wood, generally by a minimal amount, but it is never as strong as compression wood. Another interesting note stated that perhaps also defines reaction wood strength, is that although reaction wood may be stronger compared to normal wood in a tree, particularly compression wood due to the higher specific gravity or density, if you were to take normal wood of the same specific gravity, the reaction wood is definitely weaker. All in all, it just doesn't seem that reaction wood with it's fairly minimal increase in strength, if any at all, that trying to utilize it as something beyond normal wood, will not give you much useful advantage at the stump.

I read where varying species exhibit reaction wood differently, like sometimes a change in color compared to normal wood, but I couldn't find mention of conifers or hardwoods having one greater tendency or another to develop specific types of reaction wood. Not saying it couldn't be true, just that I couldn't find such mention.

 

[rskybiz]

Some very good exchange of thoughts and concepts. Jay your posts are great, your wood working experience shines through!