Here is my problem with that Paden. This illustration assumes that the object is immovable, such as iron grate fence. When the tree grows into an immovable object, the tendency is for the cambium layer to work it's way around the object. The soil where this corner in question is located is made up of glacial wind blown loess. Very finely textured, zero gravel. Some of the best farming soil in the entire state. I'm inclined to believe that due to the lack of resistance this soil exhibits, it is quite likely that this corner has 'migrated'. I met with the other surveyor yesterday and we both agreed to disagree over the position. Funny thing is, sometimes I think I might be wrong, I'm not. Given the nature of the soil and the aggressiveness of cottonwoods, I'm going to stick to my guns, in this one case. I do agree that in most instances where the corner is firmly anchored, the tree will grow around it, but not always.
Willi
> I do agree that in most instances where the corner is firmly anchored, the tree will grow around it, but not always.
I'm sure there's cases where the contrary can always be shown.
I wish I had a picture of it..but I found a twenty year old piece of rebar at a property corner, with the guard stake still right next to it, almost completely surrounded by an elm tree. It was like the tree had been liquid and "poured" around the pin and stake.
I've also seen field fence..loose field fence..grown into a tree, without a hint of deflection.
Like I said, there's probably cases indicating both views. I've just seen more of the "accretive" movement of tree growth than the "avulsive" movement. 😉
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Willi
I hold your opinion in high regard. Have you ever seen an instance where this kind of thing could have happened?
Willi
> I hold your opinion in high regard. Have you ever seen an instance where this kind of thing could have happened?
I'm assuming you mean a tree moving something by growth.
Sure. Like someone mentioned sidewalks and curb+gutter get displaced all the time by roots. I'm not sure what forces are at work in all these cases. I also have seen an elm tree that grew up through the bed of an old pickup. Sucker limbs had sprouted underneath the pickup. In their desire for sunlight they had eventually grown (6-8") out from under the pickup, lifting the rear tires off the ground by a half a foot or so.
Strange things that happen.;-)
I always assumed that the roots broke up concrete and asphalt; because their main function was to nurish the tree with water. If the surface wasn't letting water in, roots would brake it up and let in life giving mosture.
Thanks, for a clearer explanation.
A good source for deeper research into this question might be by interviewing folks who slab root burls into furniture and gun stocks. I've done some myself being a a weekend logger and sawmill owner but there are folks out there who excavate and dissect root burls on a daily basis as their main business.
Myself, I've had the pleasure of excavating out both black walnut and incense cedar root burl and sawing it up. These walnut specimens grew in river bottom loam which contained a lot of cobble. These trees typically grow to an average 4' diameter here and those with swollen root burl are particularly valuable.
My experience has been that the root burl portion extends downward from one to several feet depending on the size of tree before the individual root stems are separately defined. This root burl size generally cooresponds to the depth of a property monument.
Why I bring this up, is that in the slabbing of the root burl I have not encountered much in the way of pebbles, rock or cobble embedded within the root burl. For the most part the wood inside the root burl is fairly clean and free of material other than woody mass. Sawing these burls requires diligent effort to get all the dirt, pebbles and rock that are in the nooks and crannys around the gnarly exterior of the root wad. However once the exterior is cleaned well, the sawing of the root burl generally reveals few embedded objects. It would seem the dirt, gravels and pebbles are shoved away from the growth. Fairly large cobble however appears to provide enough resistive force to cause the contacted cambium to compress enough to restrict its growth, resulting in the surrounding growth encapsulating the rock.
My gut feeling is that a rebar placed next to a young cottonwood will be displaced to some extent before being encapsulated if the bar's bottom is not much deeper than the root burl bottom, and the bar has not penetrated any portion of the root system. Also, I think a key issue is if the root mass contacts the entire rebar at close to the same time. If the root mass only contacts a portion of the bar at first, the remaining bar is not "shoved" and the entire resistive force of the rebar is concentrated on a small area of the root growth. In other words, the force is greater than the root area x root growth pressure, causing that small portion to be encapsulated. Once a portion of the bar is encapsulated, it becomes locked in and will then have an even higher resistive force for the remaining portions of the bar as it comes into contact with the growth.
So in your case, it would depend on the timing and amount of bar length contacting the exterior of the root ball as to whether the balances of forces will be equal resulting in encapsulation after some possiblely small initial displacement, or inequal, resulting in signficant displacement of the bar.
Again though, I do encourage you to search out and contact those who saw root burl on a much more regular basis than myself. I would think they would be the best source of info on this being as they dissect root burls as a job and should be very well schooled in various species growth characteristics.
I keep looking at that photo and wondering if that is an average accumulation of forty years worth of dirt. Provided that iron pipe was set flush back in '73. I had always attributed monuments found under substantial cover to contractors or land owners bringing in fill dirt for low areas or grading purposes. Very cool find !
Willi
Chiming in from Fairbanks here. I can't speak to the horizontal, but I have seen a LOT of vertical motion with TBMs in trees, particularly when there is extensive excavation in the area. I had a project several years ago (rail siding and yard in a square mile area) where I had to run in elevations from off-site several times a month due to settling and uplift. Hundreds of thousands of yards of native material was removed and replaced with borrow, sub-ballast, ballast, and rail. TBMs around the perimeter were reliable for only a short time. I have since learned that some Alaska firms forbid the TBMs in trees practice; I can see why...
> Wait another 43 years and re-shoot it. Put the coordinates into an Excel 2057 spreadsheet and extract the deltas. Voila.
You should set up time lapse photography for the next 43 years; that would be really cool.
Dougie
If it is in an almond orchard, the pipe was undoubtedly set below the surface. It is typical to set monuments a foot or more deep in agricultural areas to allow for cultivation.
Don
> If it is in an almond orchard, the pipe was undoubtedly set below the surface. It is typical to set monuments a foot or more deep in agricultural areas to allow for cultivation.
The OP's tree is a cottonwood, the photo I posted showed an almond. It wasn't in an orchard, though it was a voluteer along a road ROW. I think the pipe was planted before the tree.
