1. Tree Rings 6 th grade science Aprende Middle School

2. Dendrochronology??

3. Dendrochronology – study of tree rings. Dendrochronologists – scientist that studies tree rings. Pronounced den – dro - kron – o - la – gee Word roots dendro (from dendros, greek for tree) chrono (from chronos, greek for time or past events) logy (from logos, greek for reason or word. “ology” indicates a study or theory)

4. Growth – varies throughout year in our climate Late Spring/Summer – wide light coloured ring (lots of growth) Late summer/autumn – narrow darker ring (little growth) Winter – dormant (no growth) What are tree rings?

5. From LTTR, Arizona One year’s growth is a dark and light ring together = annual growth ring = X X

6. From LTTR, Arizona Earlywood – appears light in colour – cells are thin walled and large in diameter Latewood – appears dark in colour – cells have thick walls and are small in diameter Total ring width = a light and dark band

7. Photos by Grassino- Mayer at UTK (see web address)

8. Year-to-year changes in the weather create the patterns. Trees respond to temperature, rainfall and other environmental conditions by altering growth. Wide rings of certain species of trees = wet years Narrow rings of certain species of trees = dry seasons

9. Ring counting cannot be based fully on the amount of rainfall in that year. There are other factors (variables) that can affect the rings of a tree.  Slope  Gradient  Sun  Wind  Soil properties  Temperature and snow accumulation.

10. The more factors a tree endures, the more variation in ring to ring growth will be present. A complacent tree will have less variation between rings because it was not affected by those factors. It had constant climate conditions. A sensitive tree will have more of a variation between rings because it was affected by those factors.

11. Marking of actual years and events on a tree section

12. 2002 The year England won the world cup? The new millennium? ? When were you born?

13. You are now going to find out more about tree ring growth and label your own tree ring!!!