Tree Age Estimate
About 60 minutes, outside, for ages 11 and up.
Where it works
Works in any outdoor space
Who it's for
ages 11 and up
Trees To Measure:
- the widest tree you can find
- the narrowest full-grown tree nearby
- two trees of the same kind, different sizes
- a tree older than the building beside it
Today's Challenge
- 1.Which tree turned out older than it looked?
- 2.What was standing here when the oldest one started?
- 3.Why might two trees the same age be different widths?
Quick Start: What you need
- 1string or tape measure
- 2notebook
- 3pen
The Goal
Measure a trunk and work out roughly how long the tree has stood there.
How to start
- 1
Gather what you need: string or tape measure, notebook and pen. Nothing else required.
- 2
Head outside and see how many you can find: the widest tree you can find, the narrowest full-grown tree nearby, two trees of the same kind, different sizes, a tree older than the building beside it.
- 3
Talk about what you are seeing. Start with "Which tree turned out older than it looked?"
- 4
Print the worksheet to check things off as you find them, and keep it afterwards.
Age The Biggest One
Measure the trunk all the way around at about chest height, write the number down, then divide it by three to get roughly the width across. Note what year that tree may have started.
Foresters estimate age from girth because most trees add a fairly steady amount each year. A tree in the open grows faster than the same kind crowded in a wood, so the estimate is a range and not an answer.
If you want to push it further
- Find a tree that predates every house on the street
- Measure the same tree again next year and see what it added
Print it and go
The worksheet has the checklist, the prompts, and a space to draw in. One page, ready for a bag or a glovebox.