Carignan Forestry Consultants

The first step in appraising, selling, or managing timber is to inventory the standing trees. The work of gathering inventory data is often called "cruising." While there are several different methods of timber cruising, all involve estimating the total volume of merchantable wood from a measured sample.

As with all statistical samples, volume estimates obtained by cruising contain a margin of error. These errors can range from 10 percent in uniform pine plantations to over 100 percent in non-uniform natural timber. That is why CFC recommends, whenever possible, making a 100% measurement of sawtimber trees (rather than sampling), especially on smaller tracts. Also, for reasons that remain unclear, volumes obtained from 100% measurements usually exceed those obtained from cruising.

Timber inventories are useful for establishing a cost basis in recently acquired property, planning depletion schedules, estate division or transfer, timber marketing, and preparing management plans.

Areas of distinctly different forest types should be inventoried separately and shown on the map that accompanies the inventory report. The report may also itemize any merchantable trees that will not be managed for timber, such as trees within streamside management zones or wildlife corridors. Except for young trees that grow very fast, timber inventories can usually be considered "current" for about two years from the date of the inventory, unless casualty losses occur.