Crown mirror - densiometer
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
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 |
