Terrestrial laser scanning (TLS) has been developed to capture detailed and highly accurate information relating to an object’s dimensions, spatial positioning, texture and colour in both two and three dimensions. It is now a widely used technology in architectural, engineering and industrial measurement applications, for example to digitize the external surface of buildings and archaeological sites. For forest monitoring purposes the use of TLS is in an early stage. While airborne laser scanners can easily be used for large scale monitoring as they are able to cover large regions, terrestrial scanners are to be carried around on the ground. TLS has been applied to forest inventory measurements (plot cartography, species recognition, diameter at breast height, tree height, stem density, basal area and plot-level wood volume estimates) and canopy characterizations. The technique also provides potential support as a non destructive tool for pre-harvest stand value and wood quality assessment.
This paper discusses TLS as potential technique for non-destructive prediction of diameter profiles of standing mature Scots pine trees. The reported results are based on measurements of 27 Scots pines from three plots scanned with TLS in a stand located in eastern Norway. Diameter at breast height (Dbh) was callipered manually on each tree. The pine trees were harvested by a single grip harvester and the stem files produced by the harvester were collected. Modern harvesters are equipped with tools to measure stem dimensions (diameter, length) and to predict the stem profile during processing. This information is part of the bucking control system of a harvester. To evaluate the potential of using TLS for producing diameter profiles of standing trees prior to harvesting the TLS based data were compared with the manually callipered diameters on each tree and with the diameters measured along each stem by the harvester.
Keywords: Terrestrial laser scanning, diameter, stem profiles, Scots pine
Authors
Flæte P.O.
Norwegian Institute of Wood Technology, Oslo, Norway
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