Timber measurement in conifer forests
Preparing for the first thinning
Measurement of timber is required for several purposes:
- to evaluate the productivity of a plantation
- to determine whether to thin or not
- to calculate the amount of timber (e.g. thin volume/ha) for sale
- to control the amount of timber harvested and sold
Thinning involves the removal of a proportion of a forest crop. This results in the remaining trees to be of higher quality and larger diameters and so increases timber value while providing income opportunities before clearfell.
Planning to measure
Forests should be measured prior to thinning. For this to happen, proper access is essential. Inspection paths should be cut following canopy
closure when lower branches are dead.
- Removing branches along two rows of trees to head height at 50m to 100m intervals using a pruning saw or light chainsaw
- Take appropriate safety measures
To calculate thin volume per hectare, the following information is needed:
- Tree stocking
- Mean diameter at breast height (mdbh)
- Thin diameter
- Top height
- Form height
- Percentage to be removed
- Production area
For further details, course notes, worked out examples and blank forms, see the list of publications below.