Crown mirror - densiometer

[−] Forest inventory

[+] Introduction to forest inventory

[+] Forest mensuration

[+] Introduction to sampling

[+] Plot design

[+] Sampling design

[+] Estimation issues

[+] Planning issues

[+] UNFCCC Implications for Forest Monitoring

[+] Forest Inventory Examples

  Forest Inventory Glossary

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.

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  Figure 1: Crown mirror - densiometer

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  Figure 2: Live view measuring crown margin

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.

1. Select an easy to recognize starting point
2. 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

Applications

• forest inventory
• environmental examination