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.
2012
Authors
Steffen AdlerAbstract
No abstract has been registered
Authors
Anders Skonhoft Vebjørn Veiberg Asle Årthun Gauteplass Jon Olaf Olaussen Erling Meisingset Atle MysterudAbstract
This paper presents a bioeconomic analysis of a red deer population within a Norwegian institutional context. This population is managed by a well-defined manager, typically consisting of many landowners operating in a cooperative manner, with the goal of maximizing the present-value hunting related income while taking browsing and grazing damages into account. The red deer population is structured in five categories of animals (calves, female and male yearlings, adult females and adult males). It is shown that differences in the per-animal meat values and survival rates (‘biological discounted’ values) are instrumental in determining the optimal harvest composition. Fertility plays no direct role. It is argued that this is a general result working in stage-structured models with harvest values. In the numerical illustration it is shown that the optimal harvest pattern stays quite stable under various parameter changes. It is revealed which parameters and harvest restrictions that is most important. We also show that the current harvest pattern involves too much yearling harvest compared with the economically efficient level.
Authors
Jahn Davik Gage Koehler Britta From Torfinn Torp Jens Rohloff Petter Eidem Robert Wilson Anita Sønsteby Stephen K, Randall Muath Alsheikh-YousefAbstract
This is a post-peer-review, pre-copyedit version of an article published in [Planta]. The final authenticated version is available online at: https://doi.org/10.1007/s00425-012-1771-2
Abstract
The Norwegian National Forest Inventory (NNFI) provides estimates of forest parameters on national and regional scales by means of a systematic network of permanent sample plots. One of the biggest challenges for the NNFI is the interest in forest attribute information for small sub-populations such as municipalities or protected areas. Frequently, too few sampled observations are available for such small areas to allow estimates with acceptable precision. However, if an auxiliary variable exists that is correlated with the variable of interest, small area estimation (SAE) techniques may provide means to improve the precision of estimates. The study aimed at estimating the mean above-ground forest biomass for small areas with high precision and accuracy, using SAE techniques. For this purpose, the simple random sampling (SRS) estimator, the generalized regression (GREG) estimator, and the unit-level empirical best linear unbiased prediction (EBLUP) estimator were compared. Mean canopy height obtained from a photogrammetric canopy height model (CHM) was the auxiliary variable available for every population element. The small areas were 14 municipalities within a 2,184 km2 study area for which an estimate of the mean forest biomass was sought. The municipalities were between 31 and 527 km2 and contained 1–35 NNFI sample plots located within forest. The mean canopy height obtained from the CHM was found to have a strong linear correlation with forest biomass. Both the SRS estimator and the GREG estimator result in unstable estimates if they are based on too few observations. Although this is not the case for the EBLUP estimator, the estimators were only compared for municipalities with more than five sample plots. The SRS resulted in the highest standard errors in all municipalities. Whereas the GREG and EBLUP standard errors were similar for small areas with many sample plots, the EBLUP standard error was usually smaller than the GREG standard error. The difference between the EBLUP and GREG standard error increased with a decreasing number of sample plots within the small area. The EBLUP estimates of mean forest biomass within the municipalities ranged between 95.01 and 153.76 Mg ha−1, with standard errors between 8.20 and 12.84 Mg ha−1.
Abstract
This study investigates the relationship between Leaf Area Index (LAI) reduction in pine stands caused by pine sawfly (Neodiprion sertifier) larva and reflectance change measured using multitemporal optical satellite data. The study was carried out in 552 Scots Pine (Pinus sylvestris)-dominated stands in southern Norway (60° 41′ N, 12° 18′ E). Post-damage Satellite Pour l'Observation de la Terre (SPOT) satellite data were calibrated to surface reflectance using reflectance products of the moderate-resolution imaging spectroradiometer (MODIS). Standwise reflectance change was then computed by subtracting a pre-damage SPOT image that had been relative calibrated to the post-damage image using histogram matching. The reflectance changes were related to changes in LAI obtained from multitemporal lidar data calibrated with field measurements made with a LiCOR LAI-2000 plant canopy analyser. The reduced needle biomass growth due to the insect damage caused an increase in reflectance on the order of 0.002–0.015 in the visible and short-wave infrared SPOT bands and a decrease of 0.01 in the near infrared (NIR) band compared with a large reference data set with normally developed stands. A cross-validated discriminant analysis showed that 79% of the damaged stands could be separated from the undamaged stands by using the SPOT data.
Authors
Juha Heikkinen Erkki Tomppo Alexandra Freudenschuss Peter Weiss Gro Hylen Gal Kusar Ronald McRoberts Gerald Kändler Emil Cienciala Hans Petersson Göran StahlAbstract
National forest inventories (NFIs) are an important source of data for reporting greenhouse gas emissions and removals for the Land Use, Land-Use Change, and Forestry sector as required by the United Nations Framework Convention on Climate Change and its Kyoto Protocol. A major limitation is that NFI resources are generally not sufficient for producing reliable information on year-to-year variation. Interpolation, extrapolation, smoothing, and/or aggregation of data from several years are therefore needed to comply with the reporting requirements for a specific year. Various methods for accomplishing this task are illustrated and evaluated based on data and experiences from the NFIs of six countries, concentrating on the estimation of the stem volume of living trees as a surrogate for tree biomass. Six main conclusions were drawn: (1) NFI data from the target years only were not sufficient for reliable estimation of annual stock change; (2) changes between whole inventory cycles (typically 5 years) could be estimated with reasonable precision; (3) simple moving average estimators of stock are problematic in the estimation of changes; (4) interpenetrating panel designs with permanent sample plots are desirable from the point of view of inter/extrapolating and change estimation; (5) data on annual growth variation and harvests are important and can be used directly in the default method, which is based on differences between increment and drain; and (6) time gaps between NFI surveys may lead to significant errors in the estimation of stock changes.
Authors
Signe Kynding Borgen Arne Grønlund Olof Andrén Thomas Kätterer Ole Einar Tveito Lars Bakken K PaustianAbstract
No abstract has been registered
Abstract
The study describes the development of surface mould and blue stain fungi on painted wooden claddings exposed to outdoor weathering. The materials consisted of Norway spruce (Picea abies) claddings that were processed from inner boards, outer boards, and edge-grained boards with known origin. Heartwood proportion, density, annual ring width, knot diameters and relative knot area were measured, and all boards were coated with the same water-borne alkyd modified acrylic paint system. Most of the tangentially sawn boards were coated on the side facing the pith, but a sub-sample was coated on the opposite side for comparison. The specimens were exposed with a 45° angle of inclination facing south in a field trial in Oslo from 2007 to 2011, and mould growth was evaluated visually according to EN 927-3. The development of mould rating was described with an ordinal logistic regression model. The model predicts expected mould rating to follow a sigmoid curve with some deviation in the first part. Neither wood properties nor manufacturing characteristics had any significant effect on the model, and this may in part be due to the use of a high performance coating system.
Abstract
The genera Leiopus Audinet-Serville, 1835 and Acanthocinus Dejean, 1821 are redescribed. New morphological differences at the generic level are described, and the importance of genitalia characters in taxonomy at both species and generic level is emphasized. Carinopus subgen. nov. in Leiopus is described from mainland China and Taiwan. Acanthobatesianus subgen. nov. in Acanthocinus is described from China, the Korean peninsula and Japan. Leiopus (Carinopus) campbelli (Gressitt, 1937) comb. nov. is transferred from Acanthocinus, and Acanthocinus (Acanthobatesianus) guttatus (Bates, 1873) comb. nov. from Leiopus. Six new species of Leiopus from China are diagnosed, described, and illustrated: L. nigropunctatus sp. nov., L. flavomaculatus sp. nov., L. ocellatus sp. nov., L. nigrofasciculosus sp. nov., L. holzschuhi sp. nov. and L. multipunctellus sp. nov. Redescriptions of L. kharazii Holzschuh, 1974, L. albivittis albivittis Kraatz, 1879, L. stillatus (Bates, 1884), L. (Carinopus) shibatai Hayashi, 1974, L. (Carinopus) fallaciosus Holzschuh, 1993, L. (Carinopus) campbelli (Gressitt, 1937) comb. nov. and Acanthocinus (Acanthobatesianus) guttatus (Bates, 1873) comb. nov. are added. A key to the generic and subgeneric levels of Leiopus and Acanthocinus, and a dichotomous key to all six new species of Carinopus subgen. nov. (Leiopus str.) from China, are provided.
Abstract
No abstract has been registered