Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2020
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Lars Sandved DalenAbstract
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Cornelya KlutschAbstract
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Cornelya KlutschAbstract
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Florencia A. Yannelli Chloe MacLaren Johannes KollmannAbstract
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Forest inventories provide predictions of stand means on a routine basis from models with auxiliary variables from remote sensing as predictors and response variables from field data. Many forest inventory sampling designs do not afford a direct estimation of the among-stand variance. As consequence, the confidence interval for a model-based prediction of a stand mean is typically too narrow. We propose a new method to compute (from empirical regression residuals) an among-stand variance under sample designs that stratify sample selections by an auxiliary variable, but otherwise do not allow a direct estimation of this variance. We test the method in simulated sampling from a complex artificial population with an age class structure. Two sampling designs are used (one-per-stratum, and quasi systematic), neither recognize stands. Among-stand estimates of variance obtained with the proposed method underestimated the actual variance by 30-50%, yet 95% confidence intervals for a stand mean achieved a coverage that was either slightly better or at par with the coverage achieved with empirical linear best unbiased estimates obtained under less efficient two-stage designs.
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Liz Veerman Karsten Kalbitz Per Gundersen O. Janne Kjønaas Filip Moldan Patrick Schleppi Emiel E. van Loon Jorien Schoorl Wim Wessel Albert TietemaAbstract
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Ryan Bright Micky Allen Clara Antón-Fernández Helmer Belbo Lise Dalsgaard Stephanie Eisner Aksel Granhus O. Janne Kjønaas Gunnhild Søgaard Rasmus AstrupAbstract
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