2. Dendrochronology

Objectives:

• Students will understand the definition of dendrochronology and why it is used
• Students will use the principles and issues to determine the potential for dating a particular wood specimen (i.e. Datable Vs non-datable wood species)

Discussion:

• Define dendrochronology (tree time study of)
• Value of precise dating
• How trees grow (from pith out, earlywood/latewood, and only living part is cambium near the bark)
• What do trees respond to? Precipitation, temperature, cloud cover, soil moisture, water table level, etc.
• Principles of dendrochronology:
• Uniformitarianism
• Limiting factors
• Site selection
• Crossdating Vs ring counting
• Replication
• Ecological amplitude
• Concerns
• False, missing rings
• Treeless areas
• Age limitations (BCP=~8700 and Irish oak=~10,000)
• Datable species
• Must crossdate
• Annual rings
• Ring width variation, circuit uniformity
• Adequate number of rings (50)

Homework:

Website 1:

www.domtar.com/arbre/english/start2.htm

1. Click on 'A Year in the Life of a Tree' (on left side)
2. Click on 'Annual Rings' (on left side AND scroll down)
3. READ
4. Click on 'Know more about annual rings?' (on right)
5. READ
6. Label the following diagram provided



www.domtar.com/arbre/english/start2.htm

7. Click on the 'BACK' button on your browser 5 times
8. Click on 'Formidable Forms' (on right side)
9. Click on 'The Conifers'
10. READ
11. Click on the 'BACK' button on your browser 2 times
12. Click on 'The Broadleaf Trees'
13. READ
14. In 2-4 sentences describe the differences between conifers and broadleaf trees.

Website 2:

www.ltrr.arizona.edu/dendrochronology.html

15. READ
16. In 2-3 sentences describe the difference between earlywood and latewood. You may also want to include drawings.
17. What is the difference between a locally absent ring a false ring?

Website 3:

http://web.utk.edu/~grissino/principles.htm

18. READ
19. In your own words (2-3 sentences), describe the Uniformitarian Principle. How is it related to studying tree rings?
20. List 3 environmental variables that may limit plant growth.
21. Explain the principle of ecological amplitude.
22. How is site selection important?
23. How is crossdating different from ring counting?

Website 4:

http://tree.ltrr.arizona.edu/lorim/lori.html

24. Scroll down
25. Click on 'Tree species suitable for tree ring dating'
26. READ
27. Click on the 'BACK' button on your browser
28. Click on 'Tree species unsuitable for tree ring dating'
29. READ
30. What characteristics make a tree species suitable for crossdating?

Website 5:

http://www.plantbio.ohiou.edu/epb/instruct/ecology/dendro.htm

This site lets you discover more about field and lab methods. You will see a video on field methods.

• class after Website assignment given

Review:

• characteristics that make a tree species suitable for crossdating

Instructions:

1. 10 Groups
2. Classify samples into suitable, unsuitable, or possibly suitable for crossdating
3. Justify your choices by explain the criteria you used to classify each sample.
4. Turn in a 5-6 sentence summary of what your group decided.