GEOS 595 E (one unit)

dendroenvironmental science

Paul Sheppard (W. Stadium 105-C1, 621-6474,

General objectives of this course

Primary: Learn by practice with a dendrochemical analysis (inorganic, non-isotopic) of selected tree rings for nitrogen content. Review other general concepts, techniques, issues, and applications of dendrochemistry as an environmental science. Concepts on the measurement and interpretation of nitrogen in tree rings were funded in part by a Small Grant for Exploratory Research From the National Science Foundation (0087007).

Colloquium meetings

We will meet for five weeks, about three hours per week. One hour per week will be spent in lecture/discussion, where we'll review pertinent literature and learn concepts. The other two hours per week will be in lab time, either together or individually, to actually do the many steps of dendrochemical analysis. These activities may take less than two hours during some weeks, more during other weeks.

Obligations and Grading

I do not plan to have any examinations is this colloquium. Final grades will be determined as follows:

Office hours and readings

Paul's office hours are essentially all the time. I'm generally around the Tree-Ring Lab most of the daytime, so your chances are good of randomly finding me for help. You could also e-mail questions and I'll reply as soon as possible.

Readings will be available in pdf format from the course website ( Note: For reading PDF files, you'll need Adobe Acrobat Reader, at least 4.0, which you can get free HERE: Adobe Acrobat

Flexible Schedule of Activities (subject to change)
1 Lecture: Why do Dendrochemistry: generally, specifically our project, bibliography
Reading: Lewis 1995: Dendrochemistry in regional ecosystem health assessments: the forest health monitoring experience.
Reading: Cutter and Guyette 1993: Anatomical, chemical and ecological factors affecting tree species choice in dendrochemistry studies.
Lab: Chisel cores, bag pieces
Lab: Grind control cores
2 Lecture: Tree physiology matters: N in plants, translocation after ring formation, uptake mechanisms
Reading: Poulson et al.: 1995. N isotope variation in tree rings.
Reading: Merrill and Cowling: 1966. Role of N in wood deterioration.
Optional Reading: Heaton: 1990. 15N/14N ratios of NOx.
Lab: Grind, bag and extract treated cores
Lab: Grind, bag and extract treated cores
3 Lecture: CNS analysis of plant tissue: a form of ion chromatography
Reading: Artiola: On Gas Chromatography
Reading: Park et al. 1992. Some advances in sample preparation techniques for X-ray densitometry and image analysis of increment cores.
Lab: Pack samples for measuring
Lab: Pack samples for measuring
4 Lecture: Environmental context of N and CO2: Effect of pollution in tree growth, role of soils
Reading: LaMarche et al. 1984. Increasing atmospheric CO2: Tree ring evidence for growth enhancement in natural vegetation.
Reading: Tilman et al. 1997. Human alteration of the global Nitrogen cycle: cause and consequences.
Lab: Measure wood
Lab: Measure wood
5 Lecture: Other dendrochemistry applications: soil acidification by proxy, non-essential element uptake
Lab: Do figures and other results
Lab: Prepare Powerpoint presentation of results
5 Noon-hour LTRR presentation
6 Research paper due

Laboratory of Tree-Ring Research, The University of Arizona
Tucson, Arizona 85721 USA
Main Office: (520) 621-1608, Fax: (520) 621-8229
Comments to Paul Sheppard: sheppard @