Northern Climate Change Schools Program
Lesson Plan

Grade Levels: 5

Author: Nancy Colberg, Jack Hulland Elementary School, Whitehorse, Yukon

Overview:
Students in grade 5 have studied climate change, starting with a general overview of climate change, and culminating with a study of specific trees in the school area, and the effects of climate change on the future of these trees.

Further information can be found at
http://www.yesnet.yk.ca/schools/jackhulland/classes/colberg/climate_change/trees/index.html

Time required:
This unit takes place over the length of the school year.

• to identify the type of forests found within the Yukon
   
  
• to adopt a tree that will be studied during the year, to see the changes, if any, from fall to spring
   
  
• to connect the changes that have happened in the boreal forests over time with the changes in climate
   
  
• to use dendrochronology to investigate the years of poor growth for our trees
   
  
• to obtain birch seeds from our greenhouse area and plant them in the spring to help clean up our environment

Resources:
Resources used for the study for the study of climate change with reference to trees, and dendrochronology:

1. Canada's Forest -- A Breath of Fresh Air; Volume Two: Climate Change; published by the Canadian Forestry Association
2. Dendrochronology: Investigating the Recent Past, a paper by Chris Marion, February 1998
3. Land of My Ancestors -- Trees and Forests, a Yukon First Nations perspective on our environment (ISBN 0-9697818-4-9)
4. Trees -- Fandex Family Field Guide (ISBN 0-7611-1204-9)
5. The Boreal Forest -- National Atlas of Canada; from Natural Resources Canada, Canadian Forest Service
6. http://nofc.cfs.nrcan.gc.ca/index_e.html: Site of the Canadian Forest Service -- Natural Resources Canada
7. http://www.sonic.net/bristlecone/dendro.html: Site that gives information about the study of dendrochronology

Choose a tree

Each student chose a tree in our school yard to observe over the length of the school year. This is the tree each also took a core sample from for the dendrochronology study.

Dendrochronology

Dendrochronology is the study of tree rings to answer ecological questions about the recent past. From the study of the tree rings we could determine the approximate age of our trees, as well as the climatic conditions each of our trees had faced over its lifetime.

First, a tool is used to bore a hole into the tree, and a core of wood is removed from the tree.

Once we obtained our core sample we returned to the classroom where we placed the sample in a wooden frame, sanded it and then counted the rings. Some of us looked at cross section ring samples to practice on while we waited to go out and get our own core samples.

We tabulated our ring counts on chart paper, and then combined our information into the following two graphs:

Age of tree:

From the dendrochronology study, we found that many of our trees were planted in 1960's, when our school was built.

Year of poor growth:

From our dendrochronology study, we found that there was a poor time of growth in the 1950's. when many fires occurred in the Yukon. The late 1990's have been very wet or very dry, showing further poor growth rings.

Thanks to Bob Sharp for introducing us to the fascinating world of dendrochronology!

Birch Seeds

In October, 2001, students picked the seed pods off of a birch tree that is growing at our school.

They divided the seeds into 3 containers:

1. Seeds to leave outside in the natural elements and weather conditions
2. Seeds to leave inside our classroom for the winter months
3. Seeds to leave inside, but then freeze 12 hours before planting

Students planted the 3 sets of seeds on January 25, 2002. They then monitored the growth of the seedlings and recorded their observations.