Tree cookies and height
Continue the story-telling aspect of nature study by helping campers to tell the stories of tree cookies (circular cross-sections of trees). To gather the necessary tree cookies, visit a local lumberman or make your own from trees cut for firewood. Make sure that you have a diverse selection of many species and growth forms.
Each new circle of wood represents one year's growth, but the tree tells a lot more than just their age. The width of each circle indicates how much the tree was able to grow in a given year. Small circles within the disc indicate where branches grew when the tree was younger. The tree cookies might also be oblong in shape, indicating a prevailing wind, a building to one side of the tree, or a hill on which the tree was growing. The NatureScope volume “Trees are Terrific,” from the National Wildlife Federation has more resources about tree cookies.
Distribute the tree cookies through the group and discuss how it represents history. Help the campers to decipher their tree cookies and get an idea for what they mean. Advanced campers can also try to count the rings and think of events that happened in the year that the tree began to grow. An interesting display for your nature area would be a large tree disc with circles labeled on it indicating years when important events in your camp's history happened.
Another interesting tree activity is to find out a tree's height, which you can accomplish in two ways. In one method, pair campers of about the same height together and have one lay on her back while her partner stands at her feet with his back towards the tree. The distance where the standing partner's head lines up with the top of the tree according to the camper laying down is the approximate height of the tree. This works because the two campers create a triangle which is the same in shape as the camper/ground and tree triangle; in effect both triangles are similar and therefore have the same ratios.
In the other method, have someone of a known height, preferably a nice round number (ie 4 feet), stand next to the tree to be measured. The rest of the group stands far away from the tree and uses their thumb at arm length to make a measure of the person's height. Then, knowing that one thumb equals four feet, the campers can walk their thumb up the tree and ascertain its height.
While these activities may appear to have a very simplistic goal, by doing them campers actively engage in finding about creation in ways that they could not before. This sense of exploration is an important virtue to nurture in the campers.