Measuring a tree

Press, 5 December 1978, Page 14

Measuring a tree

There are several ways you can measure the height of a tree, and this one, which is very easy, is called the proportional method. All you need is a friend to help you, a straight stick about two metres long, a tape measure, and chalk. Walk over to the base of the trunk and pace out 27 strides in a straight line. It does not matter how long your strides are as long as you keep them regular. Ask your friend to hold the stick vertically on the ground exactly ’ 27 strides from the tree and then make three more strides in the same direction. Mark the spot carefully and then lie on your stomach and get your eye right down on to the ground at that, point. Gaze up at the top of the tree and tell your friend to move a finger up or down

the stick until the finger coincides with the top of the tree. Next, mark the position of the finger on the stick with chalk. Now you are ready to work out the height of the tree. You know that the tree is 10 times as far from you as the stick—that is, 30 strides as opposed to three. Its height, therefore, will be ten times the height of the mark on the stick. So put your tape measure to the stick and with the help of your 10-times multiplication table, you will have a speedy answer. Measure some more trees. It is interesting finding out about a tree, how much it grows in a year and what sort, of climate it needs to develop •well. Remember to choose a longer stick if you decide to measure very tall trees.