Measuring the height of a tree using a stick or rod is a simple and effective method that requires minimal tools. Here's how you can do it:

Materials Needed:

• A straight stick or rod
• Measuring tape (to measure your distance from the tree)

Steps:

1. Find a Straight Stick
   
   Select a straight stick or rod that is equal to the length from your shoulder to your hand.

2. Hold the Stick at Arm's Length
   
   Stand a reasonable distance from the tree. Hold the stick vertically at arm's length, ensuring the top of the stick is aligned with the top of the tree, and the bottom of the stick is aligned with the base of the tree.

3. Position Yourself Properly
   
   Move forward or backwards until the stick appears to be the same height as the tree when viewed from your position. You should be able to visually align the top of the stick with the top of the tree and the bottom of the stick with the base of the tree.

4. Measure the Distance to the Tree
   
   Once the stick visually matches the tree's height, measure the distance between your standing position and the base of the tree using a measuring tape or pace it out.

5. The Distance Equals the Tree’s Height
   
   The distance you measured from where you are standing to the base of the tree is approximately the height of the tree. This works because the ratio of the stick's length to the tree's height is the same as the distance from you to the tree.

Example:

If the stick and the tree visually match when you are standing 15 metres from the tree, the tree’s height is approximately 15 metres.
https://www.youtube.com/watch?v=cDy5OjfMfZ8
https://www.youtube.com/watch?v=Pq_N3Y37qNI

This simple method provides a reasonably accurate estimate of the tree's height and can be done without any specialised equipment.

Measuring a Big Tree

While a basic identification, a photo of the tree, and noting its locality are good, please try to take the time to measure the tree, the following measurements are essential:

Trunk Circumference
The trunk circumference is measured at 1.3 to 1.4 metres above the ground. When taking this measurement:

• Ignore any lumps or burls on the trunk.
• Measure tightly around the stem for accuracy.
• If there are branches below 1.3 metres, measure them separately at right angles to the trunk at 1.4 metres.

Crown Diameter
The crown diameter refers to the width of the tree’s canopy. To measure this:

• Measure the projected crown diameter along both north-south and east-west directions for a more accurate representation.
  (The best time of day to measure the crown diameter using the tree's shade would be midday when the sun is directly overhead. During this time:
  Minimised Distortion: The sun casts the least amount of shadow distortion, meaning the shape and size of the tree's crown will be more accurately represented by its shadow.
  More Accurate Diameter: With the sun overhead, the shadow is more circular, reflecting the true crown diameter in both the north-south and east-west directions.
  If midday isn't possible, try measuring when the sun is as high as possible in the sky to reduce the distortion caused by long shadows. Avoid early morning or late afternoon when shadows are elongated, which can make the crown diameter appear larger or distorted.)

Tree Height
Measuring the tree's height is often the most challenging aspect because trees are rarely on level ground. However, height is crucial, as it greatly influences the tree size index. To measure the height:

• Try measuring the tree from various directions to get an accurate reading.
• Ideally, a clinometer should be used, which calculates height based on the angle measured from a known distance.
• Alternatively, several Android apps are available that can perform the same measurement using your smartphone.

By following these steps, you’ll be able to provide a more detailed and informative account of the tree’s size and structure.

The Big Tree Project is a project of the Dendrological Society of South Africa (DSSA),
Document Big Trees here, but they need to be registered with the DSSA.

• Dendrological Society of South Africa homepage: https://www.dendro.co.za/
• NRTSA further information https://www.dendro.co.za/trees/big-trees/
• Big tree registration form: https://www.dendro.co.za/wp-content/uploads/2016/11/Grootboomregister_Aansoek.pdf