Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2024
Forfattere
Ken Olaf StoraunetSammendrag
Det er ikke registrert sammendrag
Forfattere
Ken Olaf StoraunetSammendrag
Det er ikke registrert sammendrag
Forfattere
Ken Olaf StoraunetSammendrag
Det er ikke registrert sammendrag
Sammendrag
Monitoring surface albedo at a fine spatial resolution in forests can enrich process understanding and benefit ecosystem modeling and climate-oriented forest management. Direct estimation of surface albedo using 10 m reflectance imagery from Sentinel-2 is a promising research avenue to this extent, although questions remain regarding the representativeness of the underlying model of surface reflectance anisotropy originating from coarser-resolution imagery (e.g., MODIS). Here, using Fennoscandia (Norway, Sweden, Finland) as a case region, we test the hypothesis that systematic stratification of the forested landscape into similar species compositions and physical structures prior to the step of carrying out angular bin regressions can lead to improved albedo estimation accuracy of direct estimation algorithms. We find that such stratification does not lead to statistically meaningful improvement over stratification based on conventional land cover classification, suggesting that factors other than forest structure (e.g., soils, understory vegetation) may be equally important in explaining within-forest variations in surface reflectance anisotropy. Nevertheless, for Sentinel-2-based direct estimation based on conventional forest classification, we document total-sky surface albedo errors (RMSE) during snow-free and snow-covered conditions of 0.015 (15 %) and 0.037 (21 %), respectively, which align with those of the coarser spatial resolution products in current operation.
Forfattere
Jarle W. Bjerke Kristin Magnussen Ryan Bright Ståle Navrud Rasmus Erlandsson Eirik Aasmo Finne Hans TømmervikSammendrag
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Forfattere
Jarle W. Bjerke Kristin Magnussen Ryan Bright Ståle Navrud Rasmus Erlandsson Eirik Aasmo Finne Hans TømmervikSammendrag
Reindeer (Rangifer tarandus) pastoralism utilizes vast boreo-arctic taiga and tundra as grazing land. Highly fluctuating population sizes pose major challenges to the economy and livelihood of indigenous herder communities. In this study we investigated the effect of population fluctuations on core provisioning and regulating ecosystem services in two Sámi reindeer herding districts with contrasting fluctuation trends. We compared 50-year long time series on herd size, meat production, forage productivity, carbon footprint, and CO2-equivalence metrics for surface albedo change based on the radiative forcing concept. Our results show, for both districts, that the economic benefits from the provisioning services were higher than the costs from the regulating services. Still, there were major contrasts; the district with moderate and stable reindeer density gained nearly the double on provisioning services per unit area. The costs from increasing heat absorption due to reduction in surface albedo caused by replacement of high-reflective lichens with low-reflective woody plants, was 10.5 times higher per unit area in the district with large fluctuations. Overall, the net economic benefits per unit area were 237 % higher in the district with stable reindeer density. These results demonstrate that it is possible to minimize trade-offs between economic benefits from reindeer herding locally and global economic costs in terms of climate-regulating services by minimizing fluctuations in herds that are managed at sustainable densities.
Forfattere
Tor MykingSammendrag
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Sammendrag
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Forfattere
Johan Asplund Jenni Nordén O. Janne Kjønaas Rieke Lo Madsen Lisa Fagerli Lunde Tone Birkemoe Eivind Kverme Ronold Milda Norkute Ulrika Jansson Damian Petkovic Karlsen Anne Sverdrup-Thygeson Inger Skrede Ine-Susanne Hopland Methlie Sundy Maurice Ulrik Geiran Botten Regine Jusnes Krok Håvard Kauserud Line NybakkenSammendrag
The history of forestry in Fennoscandia spans five centuries, with clear-cutting being the dominant practice since the mid-20th century. This has led to a significant transformation of the forest landscape. In this study we investigated long-term effects of clear-cutting on forest structure and dead wood volumes. We established twelve pairs of spruce forest sites in southeastern Norway, each pair constituting of a mature, previously clear-cut stand and its near-natural counterpart with similar edaphic factors. The near-natural stands had 2.8 times higher volumes of dead wood and a larger proportion of dead wood in late stages of decay. The near-natural stands had on average 36.8 ± 9.1 m3 ha−1 of downed dead wood and 24.1 ± 6.2 m3 ha−1 of standing dead wood. Corresponding numbers for the previously clear-cut stands were 10.2 ± 2.8 m3 ha−1 and 11.9 ± 3.7 m3 ha−1. Forests with lower volumes of dead wood often also had lower connectivity of old spruce forests, which potentially have further negative effects on biodiversity. Furthermore, near-natural stands displayed greater tree size heterogeneity, resulting in a wider variation in light conditions. While no difference was observed in living tree volume, we found only weak evidence for higher basal area in the previously clear-cut stands, which had a higher stem density with more slender stems and shorter crowns. Our findings suggest that managed forests do not develop structures typical of near-natural forests before they become mature for logging. We stress the importance of a thorough site selection for studies of management effects, as forest management history may be confounded with productivity and other edaphic factors. Experimental designs like ours are vital for testing how differences in structure and deadwood volumes, driven by forest management, translate into variations in biodiversity, carbon sequestration and ecosystem functioning in future studies.
Forfattere
Eivind Kverme Ronold Sundy Maurice Vilde Åvesland Torp Celina Alexandria Kostich-Nilsen Ine-Susanne Hopland Methlie Frida Schmidt Markus Osaland Fjelde Ella Thoen Anders Kristian Krabberød Johan Asplund O. Janne Kjønaas Jenni Nordén Rune Halvorsen Tone Birkemoe Line Nybakken Inger Skrede Håvard KauserudSammendrag
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