Tree Rings Bilingual section IES Pedro de Valdivia

Starter Can you, in groups of 4, find the value of Pi? You have 4 pieces of string (20, 30, 40 and 50 cm in length), a piece of graph paper and a ruler. Go!!!

Dendrochronology? It’s all greek to me!

Dendrochronology 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)

What are tree rings? 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)

From LTTR, Arizona So one year’s growth is a dark and light ring together = annual growth ring = X X

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

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

X An aerial photo of the wooded area before the felling in X marks the area where the felled trees came from at grid reference Courtesy of Multimap

x

An area of pine trees showing how close together they are as they grow

The area after the trees were felled in autumn 2002

Young pine trees ready to plant in the cleared area in 2004

A pupil, Bielby junior, collecting measurements from felled pines

Task 1. Is there a relationship between the age (number of rings) and the diameter of the tree?

Stop here to do task

Tree RingsTree Diameter(cm)

Diameter of tree (cm)Number of tree rings

Task 2. Marking off actual years and events on a tree section

2002 The year England won the world cup? The new millenium? ? When were you born?

Put in some important dates

Task 3. Is there a relationship between the shape of the tree section and where it grew?

Look at the shape of this cross section of a tree trunk. What is unusual about the shape? Think about how it has grown Think about where it might have been in the group of trees that were cut down (go back to the photo and map on slides 9 and 10)

Task 4. Is there a relationship between the width of the summer ring and the weather that year? See slide 6

Current Useful Websites about Tree Rings and Dendrochronology Sites for primary pupils A public education programme of the Pacific Gas and Electric Company. It has a section on tree rings and an activity to draw rings on downloadable cartoon tree sections. Sites for secondary pupils Tree Rings: A Study of Climate Change A very comprehensive site that has a glossary, very readable text and a series of activities to help pupils understand the relationship between tree ring growth and climate.

Sites for teachers Henri D. Grissino-Mayer's Ultimate Tree-Ring Web Pages and /gallery.htm Ideal for a teacher who wants to know a little more about the subject. There is an extensive gallery that has some very clear images of tree rings in a variety of species that could be used to help pupils understand the principle of tree aging. Oxford Dendrochronology Laboratory Daniel Miles, Michael Worthington, and Dr Martin Bridge Technical site that would be useful for background information for the teacher. The University of Arizona. The Laboratory of Tree-Ring Research Dendrochronology A very detailed site with clear explanations about tree rings supported with comprehensive illustrations. Title: Tree Rings - Dendrochronology (2 Lessons) Prepared by: Claudia Marosz, Garden Grove Unified School District, Westminster, CA, USA A rather complex site but there is an excellent description of tree rings by Bruce Palmer (very readable for secondary pupils) if you scroll to the bottom of the page. Tree Rings. A cursory look at these well known features by Paul James, UK Published in the January 2002 edition of Micscape Magazine the on-line monthly magazine of the Microscopy UK web. An excellent gallery of sections of a variety of trees.