Haga

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==General description==
 
==General description==
Haga is a device to measure tree heights within distances of 15, 20, 25 and 30m to the tree by the [[trigonometric principle]].The distance to three can optically be determined. Additionally there is a scale for slope measurements in % implemented. Therefore a levelling board is available.  
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Haga is a device to measure [[tree height]]s within fixed distances of 15, 20, 25 and 30m to the tree by [[the trigonometric principle]] and [[measuring slope|slope]] in percent. The suitable scale can be selected by rotating the adjustment disk at the front of the device. A reference tape can be installed at the tree to determine the distance optically.
 
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<gallery widths=300px heights=300px>
 
<gallery widths=300px heights=300px>
 
File: haga01_portrait.jpg|Figure 1: Haga altimeter
 
File: haga01_portrait.jpg|Figure 1: Haga altimeter
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==Handling==
 
==Handling==
The handling of the Haga is similar to the [[Blume Leiss]]. A button enables the actor to lock the needle where the measurement value can be read.
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The handling of the Haga is very similar to the [[Blume-Leiss]] instrument.
 
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===Distance measurement===
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# Place the reference tape at the tree,
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# Determine an optimal distance to the tree by checking the view field to tree bottom and top within the forest stand - preferably 15, 20, 25 or 30m,
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===Height measurement===
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# Select the corresponding height scale by turning the adjustment disk,
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# Sight tree bottom, lock the pointer needle and remember the value,
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# Sight tree crown, lock the pointer needle and remember the value,
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# The difference between the measurements will be tree height: $h_t=h_c-h_b$.
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<gallery widths=300px heights=300px>
 
<gallery widths=300px heights=300px>
 
file: haga02_measurement-bottom.jpg|Figure 2: Live view measuring tree bottom
 
file: haga02_measurement-bottom.jpg|Figure 2: Live view measuring tree bottom
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</gallery>
 
</gallery>
  
Remember the value and measure the crown.
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{{info
The difference between the measurements will be tree height –
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|message=Note:
:<math> {h_t} = {h_c} - {h_b} </math>.
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|text= When measuring with Haga, take care that the pendulum has stopped oscillating before locking the button. Be careful of choosing the scale corrosponding to your actual distance!
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}}
 
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The difference between the measurements will be tree height –
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:<math> {h_t} = {h_c} - {h_b} </math>.
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{| class="wikitable"
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!Advantages
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!Disadvantages
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|-
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|slope correction implemented
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|correction factors list hast to be carried in the field extra
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|-
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|optical distance measurement
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|dependance on fixed scales (could be difficult in closed forest stands)
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|-
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|independence of power sources (no batteries needed)
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|in dark forest stand optical measurement is difficult
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|-
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|
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|only one needle for measurements implemented
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|-
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|
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|no digital storage of measurement results available
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|}
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==Applications==
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* [[The trigonometric principle | Height measurement]]
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==Related articles==
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* [[The trigonometric principle]]
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[[Category:]]
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{{Studienbeiträge}}
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[[Category:Clinometer]]

Latest revision as of 19:30, 29 October 2013

Contents

[edit] General description

Haga is a device to measure tree heights within fixed distances of 15, 20, 25 and 30m to the tree by the trigonometric principle and slope in percent. The suitable scale can be selected by rotating the adjustment disk at the front of the device. A reference tape can be installed at the tree to determine the distance optically.


[edit] Handling

The handling of the Haga is very similar to the Blume-Leiss instrument.

[edit] Distance measurement

  1. Place the reference tape at the tree,
  2. Determine an optimal distance to the tree by checking the view field to tree bottom and top within the forest stand - preferably 15, 20, 25 or 30m,


[edit] Height measurement

  1. Select the corresponding height scale by turning the adjustment disk,
  2. Sight tree bottom, lock the pointer needle and remember the value,
  3. Sight tree crown, lock the pointer needle and remember the value,
  4. The difference between the measurements will be tree height: $h_t=h_c-h_b$.



info.png Note:
When measuring with Haga, take care that the pendulum has stopped oscillating before locking the button. Be careful of choosing the scale corrosponding to your actual distance!


Advantages Disadvantages
slope correction implemented correction factors list hast to be carried in the field extra
optical distance measurement dependance on fixed scales (could be difficult in closed forest stands)
independence of power sources (no batteries needed) in dark forest stand optical measurement is difficult
only one needle for measurements implemented
no digital storage of measurement results available

[edit] Applications


[edit] Related articles

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