Student Worksheet

Tree Tally - Activity Instructions

Ever dreamt about being a tree scientist? In this lesson you will take on the role of scientists whose task it is to measure tree diameter in order to calculate the age of trees. After collecting data about tree diameter you will analyse your data and draw conclusions about the trees in your area.

Learning outside means limitless opportunities for imagination, inspiration, curiosity and creative thinking. Kids need to keep asking ‘why’, ‘how come’ and ‘what if’. There is no better source of questions and possibilities than investigating your natural and built environment.

Safety advice: Conduct a risk assessment of the site before heading out. Examples of potential dangers outside include large trees with dead or dying limbs, stinging, biting insects, sunburn, and dehydration. It’s also best to be prepared by having a phone and first aid kit handy.

Part A. Collecting Tree Tallies

Step 1.

Scientists measure the diameter of trees at breast height (that’s 1.4 m above the ground) as a way of telling how old trees might be. Large trees produce more nectar-rich flowers, as well as more resting and nesting spots including tree hollows as habitats.

In this lesson you will be the scientist who has been tasked with assessing the age of trees in your neighbourhood.

Step 2.

Get ready to head outside. Firstly you will need to prepare your materials:

Blindfold
Calipers
Pen/pencil
Tape measure
Tree Tally Record Table

Next you will need to select your site. You’ll need an area with at least 15 to 20 trees. If you're lucky this could be in your backyard, otherwise try a local park.

Step 3.

Head to your tree site. Before you start measuring trees you could have some fun playing a game of blindfold partners. Working with your helper, take turns at being blindfolded - this will mask the sense of sight. Whoever is blindfolded should be led to a tree which they then spend some time feeling with their hands, discussing what they are observing (e.g. what does it feel like, does it feel big, etc.). They are then led away from the tree and the blindfold removed. They should then try to locate the tree they just had their hands on.

Step 4.

Now you will start measuring the diameter of the trees. Access the Tree Tally Record Table.

Measure from the base of each tree up the trunk for 1.4 metres. At this point on the trunk use the homemade calipers or a suitable alternative to measure the diameter (width) of the trunk (known as diameter at breast height or DBH).

Record diameters at breast height data in the Tree Tally Record Table.

Part B. Organising And Analysing Tree Tally Data

Step 1.

Gather your materials:

Pen/pencil
Tree Tally Dot Plot chart and analysis - should look like this:

Step 2.

Using the Tree Tally Dot Plot chart sheet, calculate the tallies for the small, medium and large trees you measured.

Step 3.

Use your tree tally data to create a Tree Tally dot plot.

Step 4.

Answer the analysis questions.

Step 5.

If you’re connecting with other kids download the Tree Tally – Analyse the class data page and draw a stem and leaf plot.

Analysis questions

1. Which size trees are most common in your local area?

2. Explain why trees of this size are most common in your local area.

3. Explain why measuring the diameter of trees needs to use the same method.

4. Identify how your measurements could have been more accurate.

An accurate measure is close to the true value, like hitting a bullseye in a target.

1. Identify how you could improve your data collection.

Reflection

Discuss the importance of large old trees for the environment.

Taking It Further

Become involved in a fantastic nationwide citizen science project surveying tree hollows. Check out the Hollows as Homes website to see what the Royal Botanic Garden is doing to measure and assess the importance of tree hollows.

Determining tree diameter at breast height.

Outdoor Learning - Tree Tally

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