Spiraling Grain   DON BERTOLETTE
  Sep 15, 2007 10:30 PDT 

Here's a question Bob and I asked each other some time back, and I don't know that we found an answer...we noticed that some old-growth hardwood species exhibited a 'spiralling grain' as you looked up the trunk...what do you think causes that?
-DonB (Retired!)
RE: Spiraling Grain   James Parton
  Sep 15, 2007 21:00 PDT 


Actually I have wondered that myself. I saw the similar thing in a dead
Red Spruce or Frasier Fir trunk that was lying on the ground on the Deep
Gap Trail near Mt. Mitchell. The grain was wavy & twisted more than
spiral though. I took a photo of it. I would have liked to see what the
growth rings would have looked like if it had been cut cross-section.
True, this is a softwood, not a hardwood tree.
IMG_0412.jpg (114079 bytes)
 Deep Gap Trail near MT Mitchell, 2005


DSC_2864.jpg (37807 bytes)
 Flat Laurel
Creek Trail near Graveyard Fields, BRP.

James Parton

RE: Spiraling Grain   Matthew Hannum
  Sep 16, 2007 13:37 PDT 

Even hardwoods will do it, though not all of them. The big Southern Red
Oak that lives by the swimming pool in my apartment complex has a
distinct twist to it that runs up its length, yet many oaks don't have
this pattern.

I also wonder if certain species seem to twist in one direction vs.
another - I'd guess that the twist adds strength, sort of like twisting
a whole bunch of thin rope fibers together. But I wonder if it is
hardwired into the trees genetically, or if some of them just end up
doing it to resist wind, twist around competing trees, etc.
Doing the tree trunk twist...   Edward Frank
  Sep 17, 2007 11:37 PDT 

James, Don,

This is an interesting observation I have seen myself but never really
thought about. Trees typically have a spiral pattern if you look at
them when they are standing dead or fallen de-barked. I like the idea
that the twist adds to strength. Perhaps rather than rigidity it allows
some twisting of the tree in the wind without snapping it off like they
are doing with hurricane and earthquake proofing structures. It would
allow them to flex rather than break? The tree itself doesn't twist as
it grows outward because embedded fences and stuff are not twisted as
the tree grows in radius. Any other suggestions or info out there?

Spiral Grain   shamr-@aol.com
  Sep 22, 2007 14:08 PDT 
Many if not most of the lodgepole pines I see out here in the West also have that spiral pattern though you cannot see it until the tree has died and the bark fallen off. I have often wondered if this pattern allows the trees to better shed the wind by allowing them to twist a little easier in the breeze?

As to the shaggy bark on the red maple in the picture, I have seen this many times in New England though I would not call it common. I have seen it occur more often on trees growing in less than ideal conditions and am not sure that it is associated entirely with age. 

Re: Spiral Grain   Diana Lee
  Sep 23, 2007 05:42 PDT 

I have been noticing more trees with this growth pattern (still to be determined if spiral growth and spiral grain are equivilant) in much younger trees than I had observed before. I guess it's just easier to see in older trees. I"m wondering if Tim is implying that certain types of trees grow in this pattern?

On another note, this is another question that's been lingering in my mind: In Thomas Pakenham's book, Meetings with Remarkable Trees, (I believe) he states that the natural progression in a tree's life is to become hollow with age. I have a beautiful horse chestnut tree on my morning commute and it's getting quite hollow. I think about that statement and am still wondering if it's accurate.

Re: Spiral Grain   shamr-@aol.com
  Sep 23, 2007 10:53 PDT 
When I was doing veg surveys as part of my wildlife work in the Sierras I would say that at least 90% of the dead lodgepoles I saw had either a pronounced or at least slight spiral pattern in their trunks. The flacky bark on lodgepoles hides the grain when they are alive. I have not had to do Veg surveys on my current project in the Tetons so I have not looked closely but the couple I have noticed were less spiraled or straight. I will take a closer look on my next meander through the forest.

Re: Spiral Grain   Diana Lee
  Sep 23, 2007 19:02 PDT 
HI Tim,
I guess the question that begs to be asked is - have you noticed that pattern consistantly with any other type of tree? Diana
Re: Spiral Grain   Edward Frank
  Sep 23, 2007 19:17 PDT 

On this page of the website: http://www.nativetreesociety.org/fieldtrips/penna_cook_forest/cook_nov18_2005/cook_forest_cucumber.htm
is a series of photos of a fallen cucumber tree. It has a spiral ridge running up and down the length of the log. Will Blozan commented on the feature: "The ridge appears to be a fracture that severed the cambium. The spiral is
just the orientation of the wood fibers in the tree. Continued flexing along the fracture does not allow the cambium to fuse together again into a continuous layer across the fracture. Thus, the wound-wood tissue simply "plows" into its respective counterpart on the other side of the fracture and builds up a ridge of wood."

I have seen it in many different tree species. I like the idea that the spiral orientation of the grain allows the trees to twist some in the wind without breaking and may be a widespread genetic trait for many species. This is just an idea and would need to be examined in detail to determine if this is actually the case or not. But it is something that could potentially be scientifically tested, if it is not in the literature base somewhere already.

Ed Frank
Re: Spiral Grain   shamr-@aol.com
  Sep 23, 2007 19:42 PDT 

I  have noticed this pattern on species other than lodgepoles, but only a couple times that I can remember.

I must say that before having to count snags, stumps, and woody debris for work, I did not spend a ton of time looking at dead trees unless they had unique shapes or were covered in mushrooms, moss or lichen. My knowledge of grain patterns is very limited and mostly focused to the Tahoe Basin area and parts of the Sierras north and south of there as well as a sprinkling of veg work in Northern New England.

RE: Spiral Grain   Steve Galehouse
  Sep 23, 2007 19:49 PDT 

ENTS- The spiral grain condition is something I've noticed on a number
of trees, especially on chestnut carcasses and certain oaks--influenced
by coreolis effect, perhaps?(are the spirals all the same orientation?).

Re: Spiral Grain   Diana Lee
  Sep 24, 2007 10:11 PDT 
I have seen spiraling trees MANY times on hikes around the lower NY/Catskill areas.
I never really paid much attention to the species, although I will certainly start! I think your idea of the wind makes sense, however, why some trees and not others in similar environments like someone commented about oak trees 100 feet apart that didn't both spiral.
I think the lack/abundance of light in early development may be a factor. Perhaps as light becomes more available ie another tree or branch falls and the young tree starts to reach towards that side...Sounds like a good experiment! Diana

Re: Spiral Grain   Lee Frelich
  Sep 24, 2007 19:38 PDT 
Diana et al.:

Spiral grain is very common and occurs in most of the tree species in the
eastern U.S. About 95% of trees have counterclockwise spiral, and 5%
clockwise (this is data from a survey I did myself of about 20 tree species
in MN). What varies a lot among species and among individuals within
species, is how pronounced the spiral is. It varies from almost straight to
some trees that look like a spring. In some species the bark follows the
spiral and in others the bark can be straight but have spiral wood
underneath. I have never been able to find out why wood has spiral grain,
and I have asked some of the best scientists in the world.

Re: Spiral Grain   Edward Frank
  Sep 24, 2007 19:46 PDT 

In gastropods, if you view them from the top some spiral clockwise and others counterclockwise. In some species this is highly temperature dependant. Do you think trees are likewise left handed or right handed? (clock wise versus counterclockwise) as a genetic characteristic, because of some environmental characteristic, or simply by chance? I realize you and other people would just be guessing,   How about some guess people?

Ed Frank
Re: Spiral Grain   abi-@u.washington.edu
  Sep 24, 2007 19:54 PDT 


It is interesting that this is a topic which I have been working on.

The development of spiral grain in trees is a feature that is steeped in mystery. Spiral grain is uncommon in a population of young trees, but once it begins, it tends to become more abundant as trees age. To talk with a lumberman who deals with Douglas fir on rich sites, for example, and he will tell you that spiral grain is uncommon, which is good from his perspective as it will reduce the quality of the wood. But to look at old conifers, either on rich or poor sites, it is obvious that spiral grain increases as trees get old.

There are two, non-exclusive, reasons for this. One adaptive advantage of spiral grain is that roots become connected to all of the branches on a tree, rather than just the ones in line with the path of cells in the wood. Ancient trees on harsh or rocky sites typically show spiral grain patterns much more frequently than trees on rich sites. The phenomenon probably does not occur more with the seedlings of trees on these stressed trees, but the few that live to be old represent the small bit of the population that developed this character. In addition, an examination of old logs or snags will often reveal that the spiral was much less (or even absent) when the trees were younger (the wood nearer the center of the tree). As an entire tree, the tree is not only able to deal with moisture stress better, but the whole tree itself is stronger.

The popultion of trees that live to be old is a very small, and selective, subset of original seedlings.

  Sep 24, 2007 21:36 PDT 

An absolutely elegant explanation that explains much of what spiral grain I've seen...maybe one last question. I've seen both left and right spiralling grain (nothern hemisphere), seemingly independent of slope...are we looking at a 'billion butterfly sneezes" chaos theory kind of explanation for left versus right?
RE: Spiral Grain   tuce-@msn.com
  Sep 25, 2007 05:34 PDT 


The Live Oak also has the spiral pattern, I'll get some photos.
I've noticed it and have always been curious as to why trees do this.    


  Sep 25, 2007 10:25 PDT 


The random thought generator that is my brain these days, just spun this off...is there any co-incidence of chronologies when "...an examination of old logs or snags will often reveal that the spiral was much less (or even absent) when the trees were younger (the wood nearer the center of the tree))...at the point where 'spiraled-ness' first expresses is self, between o-g trees, in a stand, in a region???
RE: Spiral Grain   abi-@u.washington.edu
  Sep 25, 2007 10:48 PDT 


I do not have enough data to answer that question. That would require a fair amount of fieldwork, which I do not believe anyone has attempted.

One more observation that I did not previously mention is that the bark of trees will obscure the spiral pattern in may cases. This even holds true with thin-barked species such as lodgepole pine. I often see this in the case of lightning strikes, which travel down the spiral and often remove the bark, revealing the wood beneath. The bark on either side of the wood will often give no evidence of spiral grain, which is clearly visible in the exposed wood.

I also can see this in logs and snags, which are in the early stages of decay and still have some bark present to illustrate their ability to hide the spiral grain pattern.


Re: Spiral Grain   Lee E. Frelich
  Sep 25, 2007 11:09 PDT 

My guess is its chance which way the spiral goes in trees. A small
proportion of tornadoes are also clockwise rather than counterclockwise,
and that's probably chance. There is no real reason to think spirals in
trees and tornadoes have the same cause, but it is interesting speculation.