Wedge prism

[−] 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 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

1. Select the point for angle count sample,
2. Select starting point (tree) for the sample,
3. Move around the prism in a 360° sweep and count the trees included in the sample till starting point is reached,
4. 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.

Applications

• Bitterlich sampling
• Angle count sample

Related articles

• Bitterlich sampling

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