Accuracy of Standwise Relascope Survey

1993

10 Lit. Ang.

Unselbständiges Werk

2693

200037946

25 surveyors have estimated basal area, mean height and volume per ha at the same 10 predetermined points. Mean systematic error for basal area, mean height and volume is -11.6%, -0.1% (not significant) and -11.5% respectively. Expressed by the standard deviation the mean random error is 15.5%, 7.3% and 17.5% respectively. 19 of the 25 surveyors have estimated volume per ha in 36 stands by means of relascope survey. Mean unweighted systematic error for all the surveyors is -1.3%, and the mean unweighted standard deviation for the differences between relascope volume and the control volume is 21.8%. Mean weighted systematic error is 5.0% and the mean weighted standard deviation is 22.3% when stand areas are used as weights. The systematic error varies substantially between the surveyors.