Field Methods in Dendrochronology

Field Methods in Dendrochronology:Field Methods in Dendrochronology:

• So, if you’ve selected your site and So, if you’ve selected your site and you can even see your trees. NOW you can even see your trees. NOW WHAT?WHAT?

• Three primary means of collecting Three primary means of collecting wood samples:wood samples:• Increment borerIncrement borer• Chain sawChain saw• Archaeological drill bitArchaeological drill bit

The Increment BorerThe Increment Borer

Pressler, M.R. 1866. Der forstliche Zuwachsbohrer neuester Construction. Tharandter forstliches Jahrbuch 17: 155-223.

The Increment Borer (broken apart)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.

The Increment Borer (assembled)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.

Preparing the Increment BorerPreparing 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?

Starting an Increment Borer (I)Starting an Increment Borer (I)

Starting an Increment Borer (II)Starting an Increment Borer (II)

Coring the TreeCoring 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.

Coring the TreeCoring 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.

Coring the TreeCoring 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.

Coring the TreeCoring 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.

Extracting the CoreExtracting 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.

Extracting the CoreExtracting the Core

Wrapping up …Wrapping up …• Write down tree and site information on standard Write down tree and site information on standard

field forms, including:field forms, including:• Height estimate, dbh, crown condition, aspect, Height estimate, dbh, crown condition, aspect,

slope, topography, vegetation, location (relative slope, topography, vegetation, location (relative and GPS).and GPS).

• Photo documentation: helps in crossdating and Photo documentation: helps in crossdating and archivingarchiving

• Ensure all samples and equipment are accounted for Ensure all samples and equipment are accounted for before heading back.before heading back.

• Clean all your equipment!Clean all your equipment!

Power BorerPower Borer

ChainsawChainsaw

Archaeological Drill BitArchaeological Drill Bit