Spiral and interlocking grain in trees

Eric Frei · 23rd December 2010, 07:10 PM

We've all perhaps seen them .....

But what exactly causes it and why? External or internal factors?

Some answers here:-

Quote:

Many people thought about the cause of spiral grain and
published their opinions in hundreds of scientific articles.
The excellent book Spiral grain and wave phenomena in
wood formation by J. M. Harris (1989) lists 423 publications
which have appeared since the turn of the century.

Quote:

Up to 1958, all authors suspected spiral grain to result
from causes such as wind, rotation of the earth, injuries,
electric and magnetic fields, leverage of branches,
directional aspect, exposure, the sun, and even the moon

Quote:

Many saw its origin in LC
which grew in length intrusively to certain sides of the LC
above and below them. People wondered about the cause
of spiral grain because it seemed to have no function for the
tree in comparison with straight, vertical grain. Consider,
for example, that nobody asks what causes bird's wings.
Similarly, knowing the benefits of spiral grain for trees
would/will make questions about the cause of spiral grain
superfluous. One may, however, still wonder how and by
which mechanism trees achieve spiral grain.
The various authors did not imagine that spiral grain
evolved purposely, in response to needs, although it was
generally believed that in nature form rigorously follows
function.

Eric Frei · 24th December 2010, 08:57 AM

Some more, 2005 Southern Cross University

Quote:

Spiral grain in 181 trees from a 9-year-old plantation-grown Eucalyptus dunnii was normally
distributed with mean –0.33 degrees (to the left) and standard deviation 1.7 degrees, and was
affected by family and by crown asymmetry. Interlocking grain was common, exhibiting a mean
amplitude of 3.4 degrees (standard deviation 1.5°) and a mean wavelength of 39 mm (standard
deviation 12 mm). The relatively large amplitude of interlocking grain means that most trees will
have spiral grain that alternates between left and right during each year. The wavelength of
interlocking grain is influenced by tree size, but amplitude of interlocking is under genetic control.
Both spiral grain and the amplitude of any interlocking were heritable (h2=0.99 and 0.63
respectively).

Quote:

Spiral grain is one of several wood characteristics that may influence the utility
and acceptability of plantation-grown E. dunnii in the market place. Spiral grain is
the phenomenon where tracheids in the stem systematically have the same
inclination, forming a spiral and causing twisting in dried sawn timber through
anisotropic shrinkage (Harris 1989). The resulting twist may result in the
downgrading or rejection of large proportions of sawn boards (Balodis 1972,
Johansson et al. 2001, Kliger 2001). Spiral grain is recognised as one of the key
properties determining the suitability of wood for use as sawn timber (Raymond
2002).
Interlocking grain occurs when spiral grain varies systematically, usually cycling
between a left and right deviation. While spiral grain is considered an undesirable
trait, interlocking grain may be desirable, as interlocking grain can increase
stability, and contribute to beautiful figure (e.g., ribbon stripe).

Quote:

Spiral grain in 9-year-old E. dunnii varied between -6 and +6 degrees with mean -
0.33 degrees, and tended to increase in trees with asymmetric crowns. The
tendency to form spiral grain is heritable (h2=0.99), and is correlated with the
amplitude of interlocking grain, which typically cycles three or four degrees
around the average spiral grain. The amplitude of interlocking is heritable
(h2=0.63). The wavelength of any interlocking grain is correlated with tree size,
suggesting that it may be an annual or seasonal phenomenon. The correlation
between spiral grain and amplitude of interlocking observed in this study means
that E. dunnii trees tend not to exhibit pronounced spiral grain without
interlocking which may be problematic in timber processing.
Forest managers undertaking thinnings in E. dunnii plantations should be aware
that trees with asymmetric crowns tend to have spiral grain that is more
pronounced, and should assess this characteristic amongst other selection criteria
used for thinning.

TreeCo · 25th December 2010, 02:25 PM

I was splitting some firewood today and found a base section of a tree had some interesting grain. I don't think it's related a whole lot to this thread but here are a few photos.

Eric Frei · 26th December 2010, 06:06 PM

From the PDF attached

Quote:

Spiral grain is defined as the difference between the longitudinal
direction of the tracheids making up the wood
in trees and the longitudinal axis of the tree and is expressed
as the angle between the two directions (Matthek
and Kubler 1997). The developmental pattern of spiral
grain in Scots pine (Pinus sylvestris L.), Norway spruce
[Picea abies (L.) Karst.] and other conifers includes a
grain angle close to zero in the first annual rings, i.e. vertically
oriented tracheids. After that an inclination of the
tracheids to the left in the newly formed growth rings occurs
for 5–15 years. The maximal left-handed angle of
the tracheids usually occurs in the fifth to tenth growth
rings formed after germination. From then until the tree
approaches 30–80 years old there is a shift of the angle
in the newly formed rings from a left-handed angle of
the tracheids towards vertical and finally, after several
decades, towards a right-handed angle. In many trees the
right-handed angle never occurs (Harris 1989; Danborg
1994; Gjerdrum et al. 2002).

The formation of spiral grain is genetically controlled,
but there are also environmental factors involved
(Pyszynski 1977; Harris 1989; Mattheck 1991; Eklund
and Säll 2000). Although the genes still have to be identified,
most data indicate that the genetic control of spiral
grain is localised in the cambium and that spiral grain
formation can be coupled to cell divisions taking place in
that region (Harris 1989) and may be regulated by plant
hormones (Zagorska-Marek and Little 1986). There are
three cell division processes which are believed to cause
the development of spiral grain (cf. Hejnowicz and
Zagorska-Marek 1974). Hejnowicz (1980) proposed that
the spiral grain angle is related to the frequency of pseudo-
transverse divisions of the vertically oriented cambial
cells. The cumulative effect arising when pseudo-transverse
divisions are accompanied by intrusive growth has
been given a lot of attention for more than a century (e.g.
Hartig 1895; Bannan 1966; Kubler 1991; Larson 1994).
Intrusive growth alone, without pseudo-transverse division,
the second potentially important factor, means that
the pointed tips of elongating cambial derivatives slide
past one another thereby changing their orientation. The
two ends of a cell move in opposite directions leading to
a slight rotation of the cell. This results in a change in
the angle between the cell and the stem axis. A third process
that is suggested to be involved in the development
of spiral grain is imperfect periclinal divisions and the
cell differentiation that accompanies such divisions
(Savidge and Farrar 1984). The division is said to be incomplete
if it is partial and the newly formed wall does
not extend from one end of the cell to the other. There is,
however, still no evidence that one of the three possibilities
is more likely or unlikely than the others.

Eric Frei · 29th December 2010, 03:32 PM

The attached document was printed in The Australian Arborage 2010(not a scientific publication), although the author chooses to share his document for discussion the medium of publication doesn't leave much room for discussion compared to here. Also note that both the author and the editor are members here.

From the document:-

Quote:

Having recorded the symptomology now named Braided Reaction Wood I am sharing
my data with the Australian profession for consideration and discussion

I personally find the document erroneous in a few areas, beginning with the naming of the observed phenomena.

From the document:-

Quote:

Having recorded the symptomology now named Braided Reaction Wood

Why? Because the term means for most people a type of interwoven form, like rope or plaited hair. I doubt that is what is occurring, it would be rather profound to have timber weave itself especially when it grows by cellular division outwards. The more appropriate term used already is interlocking.

Also on page 10 the author the author states:-

Quote:

I know
of no record of this form of reactive growth in trees here in Australia.

Yet we already have documents here dated 2005 on Eucalyptus dunnii about spiral and interlocking grain. But I suppose those documents do not refer to the phenomena as "reaction wood", after all it might be just ordinary wood and without genetic mapping of a one with the interlocking grain compared to another without little will be known. It is purely an assumption that is not supported by evidence, data or fact that the tree/wood is reacting to anything at all, it might be perfectly normal for a tree with that genetic disposition to grow that way.

It has been sighted that trees with the disposition to grow spiral or interlocking grain have asymmetrical crowns, so do many gums as their form is not like say pine trees, and it could be part of the same genetical difference just like redheads have more freckles and get sunburn easier.

From the document:-

Quote:

The phenomenon of braided reaction wood appears to involve the growth of reaction
wood on both the tension and compression sides simultaneously

This alone means the grain pattern is not reacting to anything, it just happens to grow that way regardless.

I encourage readers to really question things, follow those couple of links in my signature and see if you're thinking clearly. Stop to ponder and question.

Further information and discussion is encouraged on this whole subject, even other researchers have suggested that.

I watched a CSI program where some guy drove to the crime scene in a ute (USA pick-up). His alibi was tight but they found a seed from a tree in the back of his ute. The road to the crime scene had one of the trees with a low branch, low enough that his ute hit it and a seed fell off into the back of the ute. Cut a long story short they DNA tested that tree and got a specific sequence for that tree. They tested the seed in his ute and it had the same sequence, so they got the bloke. This shows that trees within a species have unique DNA just like us, but no-one has checked these spiral and interlocking trees out thoroughly for what might be a common gene that causes it.

Drouin Tree Service · 29th December 2010, 04:51 PM

Much ado about nothing IMHO,someone comes up with a new twist and rebadges an age old subject.Nice work getting paid to write that thou i guess they are struggling for material

Eric Frei · 31st December 2010, 04:11 PM

Source: Wood in Australia, Types, properties and uses by Keith R Bootle 2005 P14 &P15

Quote:

Spiral grain

The helical orientation of grain can be caused by environmental factors such as persistent strong wind but it is more often a genetic feature which deserves attention when selecting elite trees for seed and for tree breeding.

Quote:

Interlocked grain is virtually a double spiral effect in which the alternate bands of growth have their fibres oriented in opposite directions.

25th December 2010, 02:25 PM	#3
TreeCo Mature tree Join Date: Jan 2007 Location: Georgia, USA Posts: 307	Re: Spiral and interlocking grain in trees I was splitting some firewood today and found a base section of a tree had some interesting grain. I don't think it's related a whole lot to this thread but here are a few photos. Attached Thumbnails __________________ Grow more vegetables!

29th December 2010, 04:51 PM	#6
Drouin Tree Service Veteran Heritage Status Join Date: Jan 2007 Location: Australia Posts: 1,727	Re: Spiral and interlocking grain in trees Much ado about nothing IMHO,someone comes up with a new twist and rebadges an age old subject.Nice work getting paid to write that thou i guess they are struggling for material __________________ Drouin Tree Services \| Excavator Hire - Drouin and SE Gippsland \| Landclearing Melbourne

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