Field Methods in Dendrochronology

1
Field Methods in Dendrochronology February 24,
2015
2
Field Methods in Dendrochronology

• So, if youve selected your site and you can even
  see your trees. NOW WHAT?
• Three primary means of collecting wood samples
• Increment borer
• Chain saw
• Archaeological drill bit

3
The Increment Borer
Pressler, M.R. 1866. Der forstliche Zuwachsbohrer
neuester Construction. Tharandter forstliches
Jahrbuch 17 155-223.
4
The Increment Borer (broken apart)
Grissino-Mayer, H.D. 2003. A manual and tutorial
for the proper use of an increment borer.
Tree-Ring Research 59(2) 63-79.
5
The Increment Borer (assembled)
Grissino-Mayer, H.D. 2003. A manual and tutorial
for the proper use of an increment borer.
Tree-Ring Research 59(2) 63-79.
6
Preparing the Increment Borer

• Fasten auger onto the handle via the clip.
• Spray inside and outside of auger with WD-40.
• Place the extractor some place convenient (NOT on
  the ground).
• Place the tip of the auger against the tree.
• Breast height or ground level?
• Are you coring on a slope? WHY does this matter?
• Look for a furrow in the bark. Bark is GOOD.
• Grasp the handle with one hand and the auger with
  the other.
• Push and turn simultaneously.
• Keep the shaft steady. Why is this important?

7
Starting an Increment Borer (I)
8
Starting an Increment Borer (II)
9
Coring the Tree

• Turn with both hands, even pressure on each
  handle.
• Listen for odd sounds. If it sounds strange,
  stop immediately.
• You do not want to jam the wood inside
• This occurs when the inner portion of the core
  stops.
• As you continue to turn, though, new wood is
  pushed against the jammed wood.
• This creates an awful mess inside your borer, and
  sometimes renders your borer useless for the rest
  of the trip.
• Jammed borers often must be cleared in a wood
  shop.

10
Coring the Tree

• Every few turns, check to see if the wood is
  jamming inside
• 1. Insert the extractor until it hits the core.
  Mark this location with your thumb.

11
Coring the Tree

• Every few turns, check to see if the wood is
  jamming inside
• 2. Pull the extractor out. Place the tip against
  the bark. Its distance should be the same as when
  it was inside the auger.

12
Coring the Tree

• Every few turns, check to see if the wood is
  jamming inside
• 3. If your thumb is away from the handle, your
  wood is jamming! Stop immediately.

13
Extracting the Core

• Insert the extractor under the core.
• Gently push the extractor the full length of the
  auger.
• The teeth on the extractor will bite into the end
  of the core.
• Pull the extractor gently to break the core from
  the tree.
• Cradle the core as it exits the auger in case
  pieces fall off.
• Insert the core immediately into a paper or
  plastic straw.
• Label the straw with the proper ID.

14
Extracting the Core
15
Wrapping up

• Write down tree and site information on standard
  field forms, including
• Height estimate, dbh, crown condition, aspect,
  slope, topography, vegetation, location (relative
  and GPS).
• Photo documentation helps in crossdating and
  archiving
• Ensure all samples and equipment are accounted
  for before heading back.
• Clean all your equipment!

16
Power Borer
17
Chainsaw
18
Archaeological Drill Bit