Wedge prism
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General description
The wedge prism is a small honed glass plate that is used to make an angle count sample. You can estimate basal area with basal area factors of ½, 1, 2 or 4. Each prism has a constant factor. The observer can do an angle count sample moving around the prism – while the prism is located at the sample point.
Handling
- Select the point for angle count sample,
- Select starting point (tree) for the sample,
- Move around the prism in a 360° sweep and count the trees included in the sample till starting point is reached,
- Multiply the counted number with the respective basal area factor of the prism (the result is an estimate of basal area in m² per ha)
Tree is included in the sample
Tree is not included in the sample
| Advantages | Disadvantages |
|---|---|
| independence of power sources (no batteries needed) | no digital storage of measurement results available. |
