Centroid Method: Comparison of Simple and Complex Proxy Tree Taper Functions

ABSTRACT

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.
 

References

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 - 477.
 


Use of the Centroid Method to Estimate Volumes of Japanese Red Cedar Trees in Southern Korea

ABSTRACT

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.
 

References

Coble, 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.



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