Re: [IAWA Forum] Wood cores

From: "Henri D. Grissino-Mayer" <grissino@utk.edu>
Subject: Re: [IAWA Forum] Wood cores
Date: Thu, 24 Oct 2002 08:46:35 -0400
Next Article (by Author): Re: [IAWA Forum] Wood cores "Henri D. Grissino-Mayer"
Previous Article (by Author): IAWA and Dendro "Henri D. Grissino-Mayer"
Top of Thread: Re: [IAWA Forum] Wood cores "Graeme Berlyn (FO)"
Next in Thread: Re: [IAWA Forum] Wood cores David Goldstein
Articles sorted by: [Date] [Author] [Subject]
Candace, (and others)

First, you should indeed be using a 2-thread borer design. Two-thread 
designs turn slower (8mm/0.33in per revolution) and are therefore more 
suitable for coring hardwoods. Engaging the threads in the tree trunk, 
however, is more difficult on 2-thread designs. Three-thread designs turn 
faster (12mm/0.48in per revolution) and are more suitable for softwoods.

Second, hardwoods (no matter what the genus) will more rapidly clench 
(i.e., compressed wood "rebound") the borer when coring, necessitating that 
they be cored as rapidly as possible (easier said than done). One must 
literally enter the trunk with little stoppage, extract the core, and then 
extract the borer - it helps to have two, even three people to work as a 
team doing this.

Regarding lubrication, external lubrication (WD-40, ski wax, surf wax, bees 
wax, etc.) on the auger shaft is useless. It is mostly removed at the 
bark/auger interface, and little if any penetrates into the sapwood.

Regarding extracting the core: no matter what the speed you core, the core 
itself inside the auger should be extractable, IF the borer is as sharp as 
can be and you checked to ensure that the core was not jamming inside. 
Cores can jam (compress) for various reasons: a wood defect or injury, a 
broken core, a dull borer tip, or even a pit or scratch on the inside of 
the auger. If the borer is sharp, the core should be smooth-sided and the 
extractor should slide easily under/over the core. If the borer tip is 
dull, the core will have frayed sides and again jam easily inside the auger.

Because of the speed one must core hardwoods, it's difficult to check 
whether a core is jamming inside your auger. However, for softwoods and 
some hardwoods: every 5-10 turns, stop and insert your extractor until the 
tip just touches the outer part of the core inside the auger. With your 
thumb, mark the junction on the extractor at its junction with the handle. 
Pull the extractor out and align it against the auger shaft until the tip 
touches the bark of the trunk. If you thumb is again even with the handle 
junction, you're safe. However, if your thumb is further back, even by a 
centimeter or less, then you're jamming. Stop immediately, extract the 
core, and start over.

Regarding extracting the stuck borer: if the handle turns freely, use 
parachute cord. Tie the cord many times around the shaft AND the handle at 
its junciton with the auger. Fasten the other end to a stable object 
(nearby tree, car bumper, etc.). Twist the handle to kink the cord. 
eventually the threads will engage and the auger will back out. A scissors 
jack or hoist pulley (i.e. come-along) are also useful. If the handle is 
indeed permanently stuck (i.e., the handle/auger does not turn at all), 
well, you've reached the worst-case scenario, and you may have lost a 
borer, I'm afraid.

Much of this is covered in a manuscript of mine currently being reviewed by 
the journal Tree-Ring Research. Let me know if you have any questions.

Henri

>On 02.10.23 9:22 PM, "felling@hawaii.edu" <felling@hawaii.edu> wrote:
>
> > Aloha everyone,
> >
> > I am investigating the variation in the wood anatomy of
> > populations of native Acacias here in Hawaii.  Some of the wood I
> > am collecting is very hard and I am having difficulty collecting wood
> > cores.  I am using a Haglof increment borer (10" long steel bit, 3-
> > thread, 0.2" width, made of case-hardened steel).  I lubricate the bit
> > and extractor with surf wax (my Hawaiian adaptation) before boring
> > the tree.  Some of the wood is so hard that I have problems getting
> > the wood cores.  For example: one tree did not want to let loose of
> > the borer.  I tried all sorts of tactics to extract it (ice, WD-40
> > lubricant, muscle power) but could not remove it from the tree so I
> > broke the borer close to the trunk and kissed that sample goodbye.
> > I can only surmise that heat produced during the coring (which was
> > not easy!) caused the borer to expand and it got stuck in the tree.
> > My other common problem is that once I have extracted
> > my borer (I now take it out of the tree once it becomes difficult to
> > continue to turn the borer), I cannot get the core out of the borer!
> > My extractor bends, I have to pound the extractor into the borer,
> > and then I have difficulty pulling it out.  Also, some of the wood
> > core pops out of the end of the borer and gets stuck there.
> > Does any one have any suggestions?  This wood is a far
> > cry from pine!
> > Thank you!    Candace Lutzow-Felling
> > ****************************
> > Candace Lutzow-Felling
> > Botany Department and Ecology, Evolution, & Conservation
> > Biology Program
> > 3190 Maile Way, Room 101
> > University of Hawaii, Honolulu 96822
> > (808)956-3925
> > felling@hawaii.edu
> >
> >
> > ------- End of forwarded message -------
> > ****************************
> > Candace Felling
> > Botany Department
> > University of Hawaii
> >
> >
> > ======== Welcome All Anatomists! ==========
> > About this IAWA Discussion Group, subscribing, unsubscribing, and archives:
> > http://www.cof.orst.edu/org/IAWA
> > About the IAWA and/or the IAWA Journal:
> > http://courses.ncsu.edu/classes/wps202001/IAWA/iawa.htm
> > The International Association of Wood Anatomists
> >
> >
>
>--
>KOBAYASHI, Osamu PhD. (osamuk@agr.ehime-u.ac.jp)
>http://village.infoweb.ne.jp/~fwga0159/osa-la-e.htm
>http://web.agr.ehime-u.ac.jp/~expfor/index.htm
>The University Forest
>Faculty of Agriculture, Ehime University
>Tarumi 3-5-7, Matsuyama-shi, Ehime 790-8566, JAPAN
>Tel & Fax:  +81-89-946-9913
>
>
>======== Welcome All Anatomists! ==========
>About this IAWA Discussion Group, subscribing, unsubscribing, and archives:
>http://www.cof.orst.edu/org/IAWA
>About the IAWA and/or the IAWA Journal:
>http://courses.ncsu.edu/classes/wps202001/IAWA/iawa.htm
>The International Association of Wood Anatomists

Dr. Henri D. Grissino-Mayer
Department of Geography
University of Tennessee
Knoxville, TN 37996
865.974.6029
http://web.utk.edu/~grissino/
Go to OSU College of Forestry LWGate Home Page.