A field test of the accuracy of the Barr and Stroud Type FP-12 optical dendrometer

@inproceedings{Bell1971AFT,
  title={A field test of the accuracy of the Barr and Stroud Type FP-12 optical dendrometer},
  author={John F. Bell and William A. Groman},
  year={1971}
}
Trees in a 55-year-old stand of Douglas-fir were measured with a Barr and Stroud Type FP-12 dendrometer while standing, then measured with tape and caliper after they were felled. The chi-square test of accuracy for diameters, whether determined according to size, elevation, or distance, fell within a range from ±0.222 to ±0.298 inch, and percentage accuracies varied from ±2.12 to ±3.25. The chi-square test of accuracy for stem lengths decreased from ±0.272 foot (±0.991 percent) at an average… CONTINUE READING