| Tree-Ring
Tips
Increment
Borer and Coring Tips
Field
Equipment Tips
Laboratory
Equipment Tips
COFECHA
Tips
Increment
Borer and Coring Tips
Treat your borer with respect: Increment borers are expensive, yet
take a lot of abuse when we core trees. Keep these in top condition at all
times. Be sure to clean the outside of the shaft with fine-grade steel wool
and WD-40 to remove excess resin. When storing your borer, clean it inside
and out with a gun-cleaning kit and WD-40, and coat the shaft and extractor
with WD-40 before placing in storage.
Gun
cleaning kit: Cleaning the inside of your increment borer can be
difficult, but not if you use: (1) a 22-caliber gun cleaning kit, and (2)
lots of WD-40. Any department store will carry such kits in their sporting
goods section. Be sure to get the kits used to clean 22-caliber rifles as
these will have the extensions needed for your longer borers.
Latch
hooks: Have trouble keeping the latch hooked on your increment borer?
Often when backing the borer out of a tree, the latch can come loose,
causing the handle to come off. Go to the hardware store and buy some 0.5
inch rubber O-rings used in sink faucets. Slide these down the handle and
over the latch when the borer is being used.
Sharpening
kit: Are your cores "ragged" when you pull them out of your
borer? If so, your borer needs sharpening! A sharpening kit can be
purchased from a forestry supplier, and comes with various shaped stones.
Learn how to sharpen your borer, and keep your borer sharp, always!
Otherwise, your cores will be ragged and will be prone to jamming up
inside your borer!
Cleaning
your borer: Do cores tend to jam inside your borer? If so, then your
borer needs (1) sharpening, (2) cleaning, or (3) both! Always make sure
you head to the field with a sharp borer. At the end of each day, you
should clean your borer with a gun cleaning kit and lots of lubricant.
Debris and resin left inside your borer for long periods will cause
chemical reactions that ultimately will pit and damage the inside of your
borer, causing cores to jam regularly.
Fixing
the extractor: Does the extractor (or spoon) on your borer fail to
grab the core when you insert it? First, make sure your extractor is as
sharp as possible. Use the cone-shaped sharpening stone that came with
your sharpening kit. Second, you may want to "clench" the end of
the spoon near the teeth. Place a nail that's slightly narrower than the
extractor inside the tip, and clench the extractor in a vise, using the
nail as a guide. Don't clench too much, though.
V-handles
for your borer: Sometimes the straight handles on increment borers
prevent coring in tight places (such as archaeological logs in cabins).
Create a V-handle by scoring the handle on either side, bending into a
V-shape, then welding the score line closed. A cross-brace can also help
strengthen the borer.
Gloves
for coring: After coring many trees a day, your hands and fingers can
become very sore. Purchase some fingerless gloves like those used by
bicyclists and weight lifters, making sure they have padded palms, and
your hands and fingers will be much less sore!
Flag
your extractor: Don't lose your extractor in the grass or leaf litter
around the tree you're coring! If you accidentally step on it, you may not
have a borer to use. Tie some bright colored flagging through the end loop
on the extractor handle, and you'll never lose it again.
Extractor
ethics: Try not to place your extractor on the ground beside the tree
as you can easily step on it and irreparably bend it. The ideal place?
Wedge the extractor in some bark on the tree, if possible. If not, place
it in your back pocket (my favorite), but be careful when you sit down!
Prevent
jammed borers: When coring, stop every few turns and insert the
extractor until it reaches the core. Measure off the distance with your
thumb on the end of the borer handle. Pull out the extractor and place it
alongside the borer until the tip reaches the bark. If there is a
discrepancy, your core is jamming!
Coring
in tight places: Sometimes the lower branches of trees (especially
shrubby junipers) make coring difficult with those long handles. You do
not have to use the handle that came with the borer -- the different
lengths are interchangeable! So, you can core a tree with a 20 inch borer
while turning the shaft with a 12 inch handle! Great when coring in tight
places.
Stuck
increment borer: Sometimes our borers get stuck inside a tree. Be sure
you have some parachute or heavy-duty cord with you. Tie a clove hitch
around the shaft of the borer and wrap the other end of the cord around a
nearby tree. Turn the handle counter-clockwise, thus tightening the rope.
Be very careful, though, because the borer may come out of the tree with
considerable force.
Extra
borer leverage: Sometimes coring a tree could be aided if you had
additional leverage. Try this. Use a handle that comes from an increment
borer one or two sizes larger than the one you're currently using. Be
careful, though, because additional torque is applied to the auger by this
longer handle.
Removing
a jammed core: If you do get a core stuck in your borer, check to see
how much wood is compressed. If it's less than 2.5 cm (1 in), try this.
Insert the extractor and turn the borer upside down, holding the extractor
cap. Spin the borer with the other hand. After a while, you may remove
enough wood to allow the extractor to slide beneath the jammed core.
Removing
stuck cores: If you jam your borer to the point it can't be unjammed
in the field, take the auger back to a wood shop. Using a series of narrow
to wider drill bits, use a table-mounted drill press to precision drill
the jammed wood through the tip of the auger. Then clean out any residual
wood with your gun cleaning kit.
"Pithing"
a tree: In some studies, pith (or near-pith) is required to accurately
age the tree. (1) Be sure you pull the core as it was oriented in the
tree. (2) Gauge by how far off you are (e.g., 1 cm) by looking at the
curvature on innermost rings of your core. (3) Insert the extractor into
the hole for a guide. (4) Take a second core, but offset the auger by the
distance you are from pith. Keep it parallel to the extractor.
Field
Equipment Tips
Cleaning
your chains: Are you sawing a lot of pines with your chain saw? If so,
the chain can get gummed up with resin very quickly, thus reducing its
cutting ability and performance. If you have any juniper logs nearby, run
the chain through them. This will remove most of the resin on your chain,
and rejuvenate your chain saw.
Plastic
wrap: Sometimes you may need to wrap your fragile cross sections so
that they will stay together until you get them back to the lab. Purchase
some plastic wrapping in 5 inch wide rolls (12.5 cm) (see my Supplies web
page). Alternatively, you can use 2.5 inch (5.25 cm) strapping tape.
Fishing
vest: Don't have enough pockets for all your supplies while coring
trees? Invest in a fishing vest! These have multiple pockets and can store
items such as straws, dbh tape, flagging, and sharpening kit, as well as
first aid supplies. Larger pockets in the vest can also be used to carry
small-sized cross sections!
Wooden
golf tees: Ever get a small section of wood stuck in the tip of your
borer? Never ever use the metal tip of your extractor! Instead, purchase
some wooden golf tees from a sporting goods store. These will not damage
the tip of your borer as you push out the stuck piece of wood.
Chopsticks:
Next time you visit an Oriental restaurant, save those chopsticks! Why?
They are great for removing small pieces of wood stuck in the tip of your
increment borer, and they won't damage your borer. Carry one or two in
your field vest. Remember, never ever use the metal tip of your extractor!
Coring
height gauge: Dendrochronologists regularly record their coring height
on a tree. A quick and instant height measure can be made by simply
marking the handle of your increment borer with a black felt tip pen, such
as a Sharpie, at every cm. After coring, hold this up to the trunk of the
tree and record your coring height!
GPS
units: You should always record the location of your trees based on
nearby markers and previously sampled trees. To help, invest in a
hand-held GPS unit! The better ones (about $US 350-400) are remarkably
accurate, and have even gotten me back to individual trees I previously
sampled!
GPS your trees: Modern hand-held Global Positioning Systems can quickly
document precise locations of your sampled trees to the nearest 1-3 meters,
handy in case you need to return to the field to collect cores from the
oldest tree in your study, for example! I've found that dense tree cover
mostly is not a concern for obtaining coordinates, either.
Waterproof
notebooks: Often, we have to sample while it's raining, and this can
cause our field notes to become smudged and unreadable. Invest in some
"Write-in-the Rain" brand field notebooks, available from
Forestry Suppliers and other companies. They're low-cost and will save
your field notes.
Pre-wrap
those fragile cross-sections: When collecting fragile samples for fire
history analysis, I've found it very useful to wrap the sample tightly in-situ
with plastic wrap prior to sawing with a chain saw. Make your top-cut
first, wrap the sample, then make your bottom-cut. This will keep those
fire scars from flying everywhere!
Check
the top and bottom of the fire-scarred surface: When collecting
samples for fire history, don't assume the best sections will come from
the middle of the scarred area. Often, the section containing the best
scars will be located at the top and/or bottom of the scarred surface
(also called a "catface"). If you can, collect sections from as
many areas of the scarred area.
Chalk
markers: When conducting a complete inventory of all trees in a study
plot for species composition and age structure analyses, mark trees that
have been tallied using chalk markers available from most arts and crafts
stores. These are the same types of markers used for writing "Just
married" on the windshields of automobiles (thanks Elaine Kennedy
Sutherland).
Mini
dbh tapes: When collecting tree information, dendrochronologists must
carry a lot of supplies into the field. To save space, invest in the
mini-sized diameter-at-breast-height ("dbh") tapes, capable of
measuring trees up to two meters in diameter (but that's all). These are
ultra-small and fit easily into a shirt pocket for easy access.
Portable
hand drill and bit: Sometimes we jam our borers in the field. To
remove the jammed core, use a 6mm (0.25") drill bit that has been
welded to a stock steel rod (any machine shop can do this). The final
drill bit should be the length of your borer. You can use some duct tape
wrapped around the end to hold the bit while you gently turn it inside the
auger shaft (thanks Jeff Lukas).
Compressed
air: This is nifty. When using a dry wood borer at an archaeological
or historic site, the sawdust can accumulate around the core. Buy cans of
compressed air at an office supply store (used for cleaning computer
parts) and every 12-15 mm (0.5 inch) or so, stop coring and blow out the
sawdust!
Laboratory
Equipment Tips
Pith
locators: Sometimes you need to estimate the age of a tree from cores
that did not reach pith. Using graphics software, create templates of
concentric circles (i.e., "ring") of various widths, e.g. every
1mm, 1.5mm, etc. Print these out on transparency film. To estimate the
tree age, hold the template containing rings of the appropriate width over
the innermost rings and age the tree.
Marking
your rings: I've seen that standard dissecting needles today are not
very sharp. Try this. Rather than using a needle to pin-prick your rings
once they're crossdated, use instead the lead on your mechanical pencil.
This works only with softwoods, of course, and make sure you have thick
lead (2H, 3B). In addition, you can sharpen your lead with fine-grade
sandpaper (thanks Jeff Lukas).
Sharpen
your dissecting needles: We often use dissecting needles to put the
final pin-pricks on decadal rings of crossdated pieces of wood. These tend
to get dull and sometimes come shipped rather dull. Do this. Rub the tip
of the needle back and forth across some fine-grade sandpaper, and then
inspect the tip under a microscope until the desired sharpness is
attained.
Clean
your sanding belts: Sanding belts are not cheap, so it's best to take
care of them and make them last as long as possible. Few people realize
you can clean the resin and debris off the belts using "belt
cleaners." They come in various sizes, but the best are 25 cm long
and 5 cm wide. For more information, check out my supplies page under
"Sandpaper" at the bottom.
Gummy
erasers: Need to polish up a surface on a core (or section)? Cut a
strip of fine sandpaper or sanding film (>= 320 grit) 2.5cm wide by
10cm long, and wrap this around an artist's gummy eraser (available at all
art supply stores). The eraser will conform to the contours of the core!
Beanbags
for your cores: Sometimes when you're measuring, you have to position
the core and its mount at an angle to help see the rings, especially if
the core was mounted slightly twisted. To help re-position the core, make
some small beanbags partially filled with lead shot wrapped in some sturdy
cover, such as heavy plastic or leather. Place these around the core to
hold it at the appropriate angle while measuring!
Graph
paper: It seems our favorite graph paper for creating skeleton plots
is no longer made. On the "Supplies" page, click on
"Laboratory supplies" and you'll see a link to a web site where
you can download software for creating your very own green-tinted graph
paper on your own color printer!
Masking
tape for core mounting: This was
a revelation when I learned this. Once your core has been mounted in glue
on your core mount, secure them tightly on the mount with a few strips of
masking tape. The tape is easy to remove and much easier to use than
string!
Dissecting
needles: Once the tree rings in
your wood are correctly crossdated, you should "prick" holes
permanently into your rings: one hole = every 10th decade ring, two holes
= 50th mid-century ring, three holes = century ring, and four holes =
millennium ring). To do this, use dissecting needles, also called
biological probes. High-quality metal needles are worth the extra money.
Stabilizing
wet wood: Sometimes we wish to preserve entire sections of wet wood
for analysis. Use a low-molecular liquid such as polyethylenglycol (PEG)
200 or PEG 400 to soak the wood in a PEG-bath. Low viscosity PEG 400
enables the liquid to spread in the wet wood. After drying, PEG acts as
dimensional stabilizing agent in relation to moisture (thanks Rupert
Wimmer).
Pegboard
sanding surface: To create a sanding table that will allow you to sand
cross sections of any size, nail down pegboard (available from your home
improvement store) unto a sturdy table with a wooden top. Also, purchase
the correct size wooden pegs. Hammer these into the pegboard around your
irregularly shaped cross section for a firm fit!
Map
tubes: Need a carrying case for your straws once you collect your
cores? Go to a map store or mailing outlet (like Mailboxes Etc.) and buy
those round mailing tubes in the length you require. I use one tube to
store my unused straws and another to store my straws with the cores.
Plastic works best, as paper tubes can become soggy if it rains.
Steel
wool: Need to get excess resin off your cores to see your rings?
Burnish the surface lightly with fine-grade steel wool! This will remove
the excess resin and enhance the ring boundaries.
Electric
planers: Need to get a flat surface on a cross section that has deep
chain saw cuts? On large sections, use an electric hand planer to remove
the saw cuts. On smaller sections, use a band saw to slice the section.
Both techniques should result in a new, flatter surface on the section.
Black
markers: Are you working with cross sections from a tree species with
rings difficult to see when sanded? Try this. Color half the section with
black marker. Then spread baby powder over the colored half, rub in, and
blow the remaining powder away. Rings (if any) should now be more
prominent on the colored section. Compare this half with the original
half.
Freezing
sections: Afraid of bringing home critters (ants, termites, and other
critters) to your lab? This could be problematic if termites get into your
wood collection. Take all pieces of wood to an herbarium or any place with
a low temperature deep freezer. Place your sections in these overnight to
ensure you don't have invasive insect problems.
Mold
on your cores: Does mold form inside your plastic straws on your
valuable increment cores, thus masking your ring boundaries? As soon as
possible, slit the plastic straws with a razor, thus allowing air in while
allowing the moisture in the cores to wick away. This will prevent or
reduce the amount of mold that forms on your increment cores.
Cardboard
for mounting: Running out of expensive plyboard to mount your fragile
cross sections? Did you know that many cross sections can simply be
mounted on sturdy corrugated cardboard, such as the cardboard found in
boxes for shipping heavy items. I look for these on loading docks!
Fluorescent
lighting for charcoal: Tree rings on charcoal surfaces are difficult
to see, often because of the reflection caused by regular incandescent
lights found in standard microscope illuminators. Fluorescent lights
(especially light rings) provide softer, cooler light that helps bring out
tree-ring patterns on charcoal sections! And they are not that expensive.
"Crack"
your charcoal: The guys in the dendroarchaeology section of the
tree-ring lab in Tucson taught me a neat trick to help bring out tree
rings on charcoal pieces. Take the charcoal piece in both hands (if big
enough) and carefully break the section in two along a transverse plane.
If the piece is smaller, "flick" off a piece of charcoal from
the surface with the edge of a razor blade. The rings should now stand out
very nicely.
Document
your cores: When processing your valuable cores, the person
responsible for each step in preparation should initial the bottom of the
core mount. For example, "MS by GW" (mounted and sanded by GW),
"XD by Joe H." (crossdated by Joe H.), and "ME by MS"
(measured by MS). This technique ensures careful attention to these
important steps by the technicians.
COFECHA
Tips
COFECHA
Tip #1: Be sure to check for "A" and "B" flags in
your output. An "A" flag means COFECHA could not find an
alternate dating position for a segment that correlates low with the other
series. A "B" flag is more serious and means COFECHA found an
alternate dating position. Systematic placements of flagged segments
possibly indicates a misdated series.
COFECHA
Tip #2: Need help isolating a problem (missing or double) ring in a
segment? Run COFECHA again a few times, decreasing the length of the
segments being tested each time (e.g. 50 years, 40 years, then 30 years).
Inspect the output and you'll notice you can zero in on the problem ring
more efficiently. Then be sure to go to the wood and inspect that segment
for the possible problem.
COFECHA
Tip #3: What constitutes a misdated segment or series in COFECHA?
First, look for an r-value that's twice as high as that at the zero-shift
position. Second, look for consecutive segments with the same suggested
alternate placement, e.g. +1 or -1 (the two most common alternate
placements). Third, look for an outlier ring listed by COFECHA at or
around a known problem ring (most likely a missing or extremely narrow
ring).
COFECHA
Tip #4: If you need to date some undated measurement series using
already dated series, did you know you can save the master dating
chronology created by COFECHA? In subsequent runs, enter the file name
that contains the master chronology when COFECHA asks you for the
"Crossdated tree-ring series." Then enter the file containing
the undated series when prompted. The resulting output is much simpler to
read and interpret!
COFECHA
Tip #5: See the graph with upper- and lower-case letters? This helps
identify pointer years (extremely narrow or wide rings) as well as overall
trends. The ampersand (@) symbol means a near average ring index, an
upper-case letter means a year with overall wide rings, while a lower-case
letter means a year with overall narrow rings. Each increment in the
letter equals a 0.25 standard deviation unit!
COFECHA
Tip #6: If no reference chronology is handy, and you have many undated
measurement series, first see if you have internal dating among them.
These should all be measured beginning with year "0" or year
"1." When asked to enter a dated series, hit return. Next, enter
the name of the file containing the undated series, when prompted. COFECHA
will then test each series against all others. Look for t-values at or
above 3.5!
COFECHA
Tip #7: When attempting to date multiple undated series without a
reference chronology or dated series, try not to overwhelm the analysis by
analyzing too many series at once. Start with a few (8-12) of your
measurement series with the clearest ring patterns, and enter these in
COFECHA. As they become dated against each other, use one as the anchor
and adjust all other relative dates accordingly.
COFECHA
Tip #8: Did you know you can use a reference index chronology as your
dated series when attempting to date your undated measurement series?
Simply enter the name of the file containing the index chronology when
prompted for "Crossdated tree-ring series." COFECHA should
recognize that this is an index chronology and not measurement series. If
not, COFECHA will prompt you for the format. Simple!
COFECHA
Tip #9: Here's a tip that's sure to please. Sometimes you may want to
use several index chronologies from a region to develop a single reference
chronology to date some undated series. Place all index chronologies in
one file (make sure they have the same format). Enter this file when
prompted for "Crossdated tree-ring series." You may want to turn
off detrending in COFECHA -- enter "-1" under the spline option.
COFECHA
Tip #10: Always archive your tree-ring measurements! In the Main Menu
of COFECHA, you can choose the option that says "List Ring
Measurements" and COFECHA will print out the measurements for each
series in the output. Select this option when the measurements are
completely and precisely dated, then place this output in a secure,
permanent location!
COFECHA
Tip #11: If you're conducting many runs of COFECHA to diagnose the
same data set, you don't have to print out the entire output produced by
COFECHA. In the Main Menu, select option 8 and have COFECHA print out only
those parts of the output you absolutely need, like the diagnostics in
Part 6 or the results of dating an undated series in Part 8!
COFECHA
Tip #12: To help diagnose a possible location where a misdated segment
may begin, carefully inspect Section C in Part 6 of the diagnostics. This
section lists consecutive year-to-year changes that are
very different from the mean change found in all other series. If
consecutive years are listed (e.g. 1851 1852), this could be the location
where a missing ring should be or a possible error in measurement.
COFECHA
Tip #13: So, what value of mean interseries correlation (first page in
the box, and found in Part 7 at bottom) should you have? I consider a
value of 0.40 the minimum a tree-ring data set should have. I've seen
values much higher in the American Southwest (0.55 to 0.70) while data
sets for eastern species may range from 0.45 to 0.60. Data sets with very
long complacent series, however, may have values less than 0.40.
COFECHA
Tip #14: If you're developed a network of tree-ring chronologies in an
area, you may want to check the final dating of the chronologies against
each other, and to learn where the climate signal is the weakest. Did you
know you can enter a series of chronologies from one file into COFECHA?
Simply paste all the chronologies (Index or Compact format) one underneath
another in one file! COFECHA
Tip #15: Need help isolating a problem (missing or double) ring in a
segment? Here's another tip. Run COFECHA again a few times, keeping the
same segment length being tested (e.g., 50 years or 40 years), but decrease
the amount of overlap in the segments. For example, I've found running
COFECHA testing 40 year segments overlapped by 10 years (rather than the
default 20 years) truly helps isolate problem areas! |
