Vertex

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Figure 1: Vertex III (right), transponder (middle) and 360° adapter (left)

Figure 2: Transponder fixed at a tree)

Figure 3: Vertex III

Figure 4: Sighting the target with Vertex III

General descripition

The Vertex clinometer is a device to measure distances based on ultrasonic sound and angles. It enables to directly measure tree height based on the trigonometric principle. For the measurement of distances a transponder is needed that is fixed at the tree and is an active component that submits a signal back to the Vertex. To determine the horizontal distance to the tree the transponder has to be fixed at a certain height (default 1,3 meter) that is defined in the settings menu.

The vertex clinometer allows to measure heights from variable distances to the target. The measurement results can be stored at the display to note them later down.

Handling

To switch the instrument 'on', press the 'on-button'. The menue pages can be selected by pressing the 'DME' and the 'IR' buttons. To switch the instrument 'off', press 'DME' and 'IR' simultaneously for a while. Place the transponder directly in front of the Vertex and press 'DME' to switch the transponder 'on'.

1. Distance measurement

1. Switch the transponder 'on' (when it is 'on', a quietly pulsative peep is hearable)
2. Place the transporter at the target (Figure 2)
3. Select the program for distance measurement
4. Locate the place to measure it's distance
5. Sight through the instrument pressing the 'DME-button' (Figure 3)
6. The cross (Figure 4) will shutdown, when the measurement is done
7. The horizontal distance appears at the display

2. Height measurement

1. Place the transporter at the tree (Figure 2)
2. Locate a place with a good view to tree bottom and crown
3. Select the program for height measurements
4. Determine the horizontal distance by measuring the tansponder (Figure 5)
5. Measure tree bottom (Figure 6) and tree crown (Figure 7)
6. Read the resulting height (Figure 8: Horizontal distance = 7,9m, tree height = 24,5m)

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  Figure 5: measurement of transponder

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  Figure 6: measurement tree bottom

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  Figure 7: tree crown measurement

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  Figure 8: Display results

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  Figure 9: Installation of transponder at a plot centre

3. Distances within a centre plot

1. Place the transponder at the 360° adapter and locate both vertically at the centre point (Figure 9)
2. Go to the tree and locate the instrument at the tree to measure directly the distance

Advantages	Disadvantages
slope correction implemented	height values from leaning trees are underestimated
Notes: Ultra waves can be affected by sounds of crickets and the sound of purling water (experiances done in Indonesia and Germany), so that the height values are biased. The internal temperature of the Vertex needs to be the same as the external temperature - if not the values are biased Applications Height measurement Distance to tree Measuring slope Related articles The trigonometric principle Bitterlich sampling Web Links Haglöf Sweden