Cubic-meter volumes estimated from simple and complex proxy taper functions
were compared to observed volumes of loblolly pine (Pinus taeda, L.) and ponderosa
pine (Pinus ponderosa, Dougl. ex Laws.) trees to evaluate accuracy (bias
and precision) in the centroid method. The results of this investigation
showed no clear evidence that a more complex proxy taper function is more
accurate than a simple function. The results also support previous
studies that show accurate volumes of standing trees may be obtained using
the centroid method, which requires only one upper-stem diameter measurement.
Coble, D.W., and H.V. Wiant, Jr. 2000. Centroid method: Comparison
of simple and complex proxy tree taper functions. Forest Science 46(4):473
Use of the Centroid Method to Estimate Volumes of Japanese Red Cedar Trees in Southern Korea
Cubic-meter volumes estimated from two proxy taper functions were compared
to observed volumes of Japanese red cedar trees (Cryptomeria japonica, D.
Don) to evaluate accuracy in the centroid method. Centroid volume estimates
were also compared to volume estimates from existing whole-tree volume equations
developed for another geographic region. This study found that one
proxy function produced unbiased volume estimates while the other was biased.
Volume estimates from the whole-tree equations were also biased. However,
the volume estimates from the whole-tree equations were more precise than
those from the centroid method. These results support previous studies
that the centroid method can produce reliable volumes of trees when no other
reliable volume equations exist.
ReferencesCoble, D.W., and Y.J. Lee. 2003. Use of the centroid method to estimate volumes of Japanese red cedar trees in southern Korea. Korean Journal of Ecology 26(3):123 - 127.