Crown mirror - densiometer
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==General description== | ==General description== | ||
The crown mirror consists of a gimble grip, where a plumb tube is installed with a mirror and a visor cross. The visor cross divides the canopy into 4 quads. | The crown mirror consists of a gimble grip, where a plumb tube is installed with a mirror and a visor cross. The visor cross divides the canopy into 4 quads. | ||
The crown mirror densiometer is a device to plumb crown width, crown radius, crown area shadow or the crown projection to estimate the degree of canopy. A plumb-pipe with a mirror and a cross line are gimballed. | The crown mirror densiometer is a device to plumb crown width, crown radius, crown area shadow or the crown projection to estimate the degree of canopy. A plumb-pipe with a mirror and a cross line are gimballed. | ||
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file: crown-mirror-01_portrait.jpg|Figure 1: Crown mirror - densiometer | file: crown-mirror-01_portrait.jpg|Figure 1: Crown mirror - densiometer | ||
file: crown-mirror-02_measurement.jpg|Figure 2: Live view measuring crown margin | file: crown-mirror-02_measurement.jpg|Figure 2: Live view measuring crown margin | ||
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* [[environmental examination]] | * [[environmental examination]] | ||
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[[Category:Measurement devices]] | [[Category:Measurement devices]] | ||
Latest revision as of 12:53, 27 October 2013
[edit] General description
The crown mirror consists of a gimble grip, where a plumb tube is installed with a mirror and a visor cross. The visor cross divides the canopy into 4 quads. The crown mirror densiometer is a device to plumb crown width, crown radius, crown area shadow or the crown projection to estimate the degree of canopy. A plumb-pipe with a mirror and a cross line are gimballed.
Figure 1: Crown mirror - densiometer
Figure 2: Live view measuring crown margin
[edit] Handling
To project the crown margin down to the ground, a manual lead and a line can be used to mark the crown limit on the ground – later the crown area can be measured at the ground.
- Select an easy to recognize starting point
- Walk around the crown perimeter and observe the corresponding crown through the instrument till you reach the starting point
A field survey with the crown mirror densiometer can be improved by using additionally e.g. a walktax for the crown area conduction.
| Advantages | Disadvantages |
|---|---|
| hinges with ball bearings | no application to measure or calculate directly canopy cover values |
