Estimating the volume
of wood in your forest
Plantations are established for a variety of reasons,
but
the most common
reason for planting in New Zealand is to grow wood. If you are a
wood grower, then you'll benefit from being able to estimate the amount
of wood in the stems of your trees at any particular time. It's
also useful to have estimates of the number of trees/hectare, tree
diameters and their heights, because these variables influence both
value and future growth. This series of web pages can help you plan and
implement a measurement of your forest blocks (known as an
"inventory"), and then use the inventory program within the "Tree
Planter's record system" (TPRS) to calculate not just estimates of
height, diameter, stocking and volume, but how good your estimates
are. Estimates for trees that exceed about 7 metres in average
height can be used with "growth and yield models" to estimate likely
future volumes. Growth and yield models are also available as
programs within TPRS.
A word of caution: Volume of
wood is not the only thing that determines the value of a
woodlot. Rate of growth (for immature woodlots), the proportions
of different log types that it will produce, costs of harvesting and
transport, and market preferences at time of harvest will also
influence value. If you wish to obtain a precise estimate of the
value of your forest, then you should consult a trained forester,
preferably a registered forestry consultant.
Click on the links below to learn how to do an inventory for
yourself. If you are new to forest inventory, you should read the
pages in order.
What do you need to measure?
Measurement tools and techniques
Laying out your plots
Conducting your inventory
Entering your plot and tree measurements into
TPRS
Using the Inventory plugin to obtain estimates
What determines the
precision of your estimates?
A "quick, dirty and cheap" inventory for rough estimates