Skip to main content
SLU publication database (SLUpub)
Conference paper - Peer-reviewed, 1998

On the accuracy of line transect sampling of rare forest objects

Lämås, Tomas; Ståhl, Göran

Abstract

For timber production purposes, plot-based inventory methods, such as circular plot sampling, are widely used. For rare objects, however, other methods are likely to be more cost-efficient and, consequently, studies of alternative methods are needed. In line transect sampling, the surveyor walks through the forest along inventory lines, and when an object of interest is noticed, the perpendicular distance between the object and the line is measured. After the inventory, a probability-of-detection function is estimated. Thereby, unbiased estimates are obtained, although objects in the neighbourhood of the line are not always noticed. The method has, for example, been used for inventory of bird populations and should also be a useful method for acquiring data on rare forest objects of interest for nature conservation (e.g. individual plant and animal species, snags and logs). The shape of the (true) probability-of-detection function depends on, for example, sighting conditions and number of objects. The accuracy of the method depends, among other things, on how well this function can be estimated. If only a few objects are found in the inventory, the function is likely to be poorly estimated. In this study, some characteristics of the line transect sampling method were investigated by Monte-Carlo simulation. Effects of the number of objects found on the estimation of the probability-of-detection function and, consequently, the accuracy of the inventory method were investigated. Furthermore, the influence of the spatial distribution of the objects (Poisson or clustered distribution) was studied.

Published in

Forestry Sciences
1998, Volume: 51, number: 18, pages: 273-281
Title: Assessment of Biodiversity for Improved Forest Planning : proceedings of the Conference on Assessment of Biodiversity for Improved Planning
ISBN: 978-0-7923-4872-6
Publisher: Springer

Conference

Conference on Assessment of Biodiversity for Improved Planning

      SLU Authors

    • Lämås, Tomas

      • Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences
      • Ståhl, Göran

        • Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences

      UKÄ Subject classification

      Forest Science

      Publication identifier

      DOI: https://doi.org/10.1007/978-94-015-9006-8_26

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/41905