How To Measure Tall Trees With Your Hand

Lime trees, as the Tilia species is known in Britain, are tall broadleaf trees. There are small-leaved limes and large-leaved limes, and both have the same characteristic in the leaf. The leaves are lop-sided. One side of the base of the leaf is smaller and the base is set higher than the other side. So when they are in leaf they are very easy to recognise.

In winter, with the trees being so close to where we live, I have come to recognise the upward slant of the branches and the fine tracery at the outer edges of the crown.

Limes are also sometimes called Linden trees in Britain, but that is usually in classical literature. Whichever name, they are are not related to the Citrus family of trees that produce the limes that we eat.

Google says that the tree is called linden, lime, or basswood in North America.

They can grow to be very old, more than a thousand years old. I don’t know how old these trees in this park in Cambridge are, but I pass them often and I keep noticing how very tall they are.

On the way into town from where we live, we walk down a footpath – an avenue of these trees. Sometimes I look up at the trees, and time and again I am surprised at how very tall they are.

Looking up and walking along is being in a different world, especially when the sun is shining. It is such a positive experience that I can feel my endorphins screaming with delight.

It is easy enough to walk along while looking up – people are used to stepping out of the way of people staring at their phones as they walk along.

I like the trees a lot and because they are so close to home – we can see them right in front of our house – I have got to know them, and familiarity breed affection.

The books say lime trees can reach 140 feet (40 metres) in height, and I decided to find out the height of the tallest of lime tree in the park.

I knew that calculating the height of the tree would involve angles and trigonometry, but I wanted an easy method.

I googled for how to measure height. One method suggested using a square of card folded to a triangle with a 45° angle and then moving back from the tree until, with the card held level to the ground, the top of the card matched the top of the tree.

When I could see the top of the tree when I looked along the length of that 45° angle I would be the same distance from the tree as the height of the tree. Easy.

Another suggestion used just the span of the outstretched hand with the fingers and thumb splayed open vertically. It relied on the principle of the distance from the span to the eye with the arm outstretched being three times the width of the span.

So moving backwards from the tree to a distance where the span neatly coincided with the top and bottom of the tree would be a distance three times the height of the tree. Easier still.

I measured 80 strides to the tree when my hand span encompassed the height to the tree with arm outstretched. My stride is about a metre, so that makes the tree 27 metres or 88 feet tall.

I wonder where an example of a lime tree 140 feet tall, is?