Caliper vs. diameter tape

[−] 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

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Characteristics and advantages and disadvantages of calipers and tapes.

• Tapes are easier to carry than calipers in many circumstances, in particular when understory is dense.

• Measuring diameter with calipers is faster than with tape.

• The caliper has an upper bound of tree diameters that can measured. Bigger trees can not be measured. With the tape, there is the possibility to measure the diameter of any big tree as one may determine the perimeter by putting various tape together.

• For felled logs, calipers can more easily be used whereas it is often difficult to pass under the logs with tapes.

• While there is, for geometrical reasons, a systematic overestimation when using the tape, we have more variability in caliper measurements, because for irregularly shaped trees the reading depends on the direction from which the caliper is used

• On permanent observation plots, where all trees are measured in regular intervals, it is important to secure consistency between the repeated measurements. Consistency is created by using a diameter tape. When using a caliper, it is important to defined and record from which direction each tree had been measured so that the following measurements can be done from exactly the same direction (e.g. the open end of the caliper’s beam always shows to the plot center).