Field Methods in Dendrochronology

1. Field Methods in Dendrochronology

2. Field Methods in Dendrochronology: • So, if you’ve selected your site and you can even see your trees. NOW WHAT? • Two primary means of collecting wood samples: • Increment borer • Chain saw • Forget the chain saw for this class …

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. • Turn one or two full turns out. • 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. Extracting the Core

16. 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!

17. Using a Chain Saw