Abstract

Transect relascope sampling is a recently proposed method for making efficient inventories of coarse woody debris on the ground. However, before the method call be recommended, its performance in the field requires investigation. This paper presents the results of a field study in which 11 surveyors tested the method in two coniferous stands in northern Sweden. The average bias introduced by the surveyors was moderate under normal sighting conditions, but underestimation was substantial when combining a small relascope angle with poor sighting conditions. In all cases, the differences between the systematic errors of individual surveyors were substantial. The conclusion is that transect relascope sampling is not an appropriate method when the demand for unbiased estimates is high, e.g. in connection with long-term monitoring, but that the method can be useful as a first phase in double sampling or in ocular-based inventories aimed at identifying biologically valuable areas.

Keywords

analysis of variance; line intersect sampling; measurement errors; multi-resource forest inventory; surveyor bias

Published in

Scandinavian Journal of Forest Research
1999, volume: 14, number: 6, pages: 552-557
Publisher: SCANDINAVIAN UNIVERSITY PRESS

Authors' information