Table 1. Quantity of measured sample trees by measurement instrument, measured variable, observer, and tree species. Measured variables are diameter at breast height (dbh) and upper stem diameter (d6). | |||||||

Instrument | Sonar | Criterion | Calliper | ||||

Variable | dbh | dbh | d6 | d6 | |||

Observer | 1 or 2 | 1 | 2 | 1 | 2 | 1 | 2 |

Scots pine | 112 | 108 | 107 | 108 | 107 | 59 | 49 |

Norway spruce | 142 | 130 | 101 | 130 | 101 | 52 | 78 |

Birch | 64 | 61 | 35 | 61 | 35 | 25 | 35 |

Aspen | 4 | 4 | 4 | 4 | 4 | 3 | 1 |

Grey alder | 4 | 3 | 3 | 3 | 3 | 1 | 2 |

Sample trees total | 326 | 306 | 250 | 306 | 250 | 140 | 165 |

Table 2. Standard deviation for diameter at breast height (dbh) and upper stem diameter (d6) for Criterion with reference to earlier research with a steel calliper. Number of paired observations is n, maximum standard deviation for Criterion is S_{upper}, referenced standard deviation for Calliper is_{ }S_{ref} and Criterion standard deviation is S_{CRI}. Measurement unit is shown in millimetres. | ||||||

Species | variable | n | n (outliers) | S_{upper} | S_{ref} | S_{CRI} |

All | dbh | 553 | 3 | 19.96 | 6.90 | 18.73 |

Scots pine | dbh | 215 | 0 | 16.40 | 6.90 | 14.87 |

Norway spruce | dbh | 231 | 0 | 21.50 | 6.90 | 20.36 |

Birch and other | dbh | 107 | 3 | 22.82 | 6.90 | 21.75 |

All | d6 | 519 | 4 | 16.88 | 7.00 | 15.36 |

Scots pine | d6 | 205 | 0 | 11.39 | 6.00 | 9.68 |

Norway spruce | d6 | 214 | 0 | 16.51 | 7.00 | 14.95 |

Birch and other | d6 | 100 | 4 | 20.05 | 7.00 | 18.79 |

Table 3. Standard deviation and bias for Criterion with reference to the mean measurement value. Diameter at breast height is dbh, upper stem diameter d6, number of paired observations is n, standard deviation is S_{CRI} and measurement unit is shown in millimetres. | ||||||

Species | variable | n | S_{CRI} | S_{CRI }(%) | bias | bias (%) |

All | dbh | 556 | 12.21 | 4.99 | –3.31 | –1.35 |

Scots pine | dbh | 215 | 10.67 | 4.40 | –0.96 | –0.40 |

Norway spruce | dbh | 231 | 12.29 | 4.76 | –4.11 | –1.59 |

Birch and other | dbh | 110 | 14.64 | 6.62 | –6.20 | –2.81 |

All | d6 | 519 | 8.88 | 4.47 | –2.44 | –1.23 |

Scots pine | d6 | 205 | 7.73 | 4.01 | –1.73 | –0.90 |

Norway spruce | d6 | 214 | 9.45 | 4.33 | –3.27 | –1.50 |

Birch and other | d6 | 100 | 9.78 | 5.79 | –2.12 | –1.25 |