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Evaluating the accuracy of ALS-based removal estimates against actual logging data

Authors
  • Vähä-Konka, Ville1
  • Maltamo, Matti1
  • Pukkala, Timo1
  • Kärhä, Kalle2
  • 1 University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, Joensuu, FI-80101, Finland , Joensuu (Finland)
  • 2 Stora Enso, Wood Supply Finland, Helsinki, FI-00101, Finland , Helsinki (Finland)
Type
Published Article
Journal
Annals of Forest Science
Publisher
Springer Paris
Publication Date
Aug 27, 2020
Volume
77
Issue
3
Identifiers
DOI: 10.1007/s13595-020-00985-7
Source
Springer Nature
Keywords
License
Green

Abstract

Key messageWe examined the accuracy of the stand attribute data based on airborne laser scanning (ALS) provided by the Finnish Forest Centre. The precision of forest inventory data was compared for the first time with operative logging data measured by the harvester.ContextAirborne laser scanning (ALS) is increasingly used together with models to predict the stand attributes of boreal forests. The information is updated by growth models. Information produced by remote sensing, model prediction, and growth simulation needs field verification. The data collected by harvesters on logging sites provide a means to evaluate and verify the accuracy of the ALS-based data.AimsThis study investigated the accuracy of ALS-based forest inventory data provided by the Finnish Forest Centre at the stand level, using harvester data as the reference. Special interest was on timber assortment volumes where the quality reductions of sawlog are model predictions in ALS-based data and true realized reductions in the logging data.MethodsWe examined the accuracy of total volume and timber assortment volumes by comparing ALS-based data and operative logging data measured by a harvester. This was done both for clear cuttings and thinning sites. Accuracy of the identification of the dominant tree species of the stand was examined using the Kappa coefficient.ResultsIn clear-felling sites, the total harvest removals based on ALS and model prediction had a RMSE% of 26.0%. In thinning, the corresponding difference in the total harvested removal was 42.4%. Compared to logged volume, ALS-based prediction overestimated sawlog removals in clear cuttings and underestimated pulpwood removals.ConclusionThe study provided valuable information on the accuracy of ALS-based stand attribute data. Our results showed that ALS-based data need better methods to predict the technical quality of harvested trees, to avoid systematic overestimates of sawlog volume. We also found that the ALS-based estimates do not accurately predict the volume of trees removed in actual thinnings.

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