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.
2006
Authors
L.H. Pardo P.H. Templer C.L. Goodale S. Duke P.M. Groffman M.B. Adams P. Boeckx J. Boggs J. Campbell B. Colman J. Compton Bridget A. Emmett Per Gundersen O. Janne Kjønaas G. Lovett M. Mack A. Magill M. Mbila M.J. Mitchell G. McGee S. McNulty Knute J. Nadelhoffer S. Ollinger D. Ross H. Rueth L. Rustad P. Schaberg S. Schiff Patrick Schleppi J. Spoelstra W. WesselAbstract
N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar d15N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root d15N and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar d15N than the regional driver of N deposition. Foliar d15N increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar d15N was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root d15N was more tightly coupled to forest floor properties than was foliar d15N. We observed a pattern of decreasing foliar d15N values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar d15N included species composition and climate. Relationships between foliar d15N and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar d15N, due to the importance of ammonium deposition in this region. Our results suggest that examining d15N values of foliage may improve understanding of how forests respond to the cascading effects of N deposition. Introduction Nitrogen saturation is the process by which chronically elevated N inputs alter forest ecosystems, ultimately resulting in increases in ecosystem N loss (Aber et al. 1989; 1998). N saturation can result in detrimental plant responses and have serious consequences for forest health (Nihlgard 1985; Aber et al. 1989; Schaberg et al. 2002) and may impact forests in many regions (Dise et al. 1998; Aber et al. 2003). Therefore, developing indicators useful for determining whether a forest is at N saturation and for predicting when a forest is nearing N saturation is valuable. Such indicators would facilitate both forest management and understanding of N cycling in forest ecosystems.
Authors
Linda H. Pardo P. H. Templer C. L. Goodale S. Duke P. M. Groffman M. B. Adams P. Boeckx J. Boggs J. Campbell B. Coleman J. Compton Bridget A Emmett Per Gundersen O. Janne Kjønaas G. Lovett M. Mack Alison Magill M. Mbila Myron J. Mitchell G. McGee Steven McNulty Knute Nadelhoffer S. Ollinger D. Ross H. Rueth Lindsey Rustad P. Schaberg Sheryl Schiff Patrick Schleppi J Spoelstra Wim WesselAbstract
N saturation induced by atmospheric N deposition can have serious consequences for forest health in many regions. In order to evaluate whether foliar d15N may be a robust, regional-scale measure of the onset of N saturation in forest ecosystems, we assembled a large dataset on atmospheric N deposition, foliar and root d15N and N concentration, soil C:N, mineralization and nitrification. The dataset included sites in northeastern North America, Colorado, Alaska, southern Chile and Europe. Local drivers of N cycling (net nitrification and mineralization, and forest floor and soil C:N) were more closely coupled with foliar d15N than the regional driver of N deposition. Foliar d15N increased non-linearly with nitrification:mineralization ratio and decreased with forest floor C:N. Foliar d15N was more strongly related to nitrification rates than was foliar N concentration, but concentration was more strongly correlated with N deposition. Root d15N was more tightly coupled to forest floor properties than was foliar d15N. We observed a pattern of decreasing foliar d15N values across the following species: American beech>yellow birch>sugar maple. Other factors that affected foliar d15N included species composition and climate. Relationships between foliar d15N and soil variables were stronger when analyzed on a species by species basis than when many species were lumped. European sites showed distinct patterns of lower foliar d15N, due to the importance of ammonium deposition in this region. Our results suggest that examining d15N values of foliage may improve understanding of how forests respond to the cascading effects of N deposition.
Abstract
We examined growth responses of Norway spruce using tree-ring series from increment cores and monthly climate variables over the period 19001998. The 1398 cores were selected from 588 plots scattered all over Norway. We correlated tree-ring indices with temperature, precipitation, Palmer drought severity index and length of the growing season.The weather in June had the largest influence on ring widths. However, two different, and almost opposite, response types were found: Tree growth was restricted by June precipitation in the lowlands in southeastern Norway, but by the June temperature in other regions and at high altitudes.In order to define the shift between these two main response types, we correlated response functions with various 30-year mean climatic variables, including humidity and aridity indices. The 30-year mean June temperature was the variable most clearly showing this shift in response, with a threshold at 1213C. At sites with normal temperature below this threshold, spruce responded positively to unusually warm and dry June months, and vice versa.
Abstract
There is increasing awareness of the need to monitor trends in our constantly changing agricultural landscapes. Monitoring programmes often use remote sensing data and focus on changes in land cover/land use in relation to values such as biodiversity, cultural heritage and recreation.Although a wide range of indicators is in use, landscape aesthetics is a topic that is frequently neglected. Our aim was to determine whether aspects of landscape content and configuration could be used as surrogate measures for visual landscape quality in monitoring programmes based on remote sensing.In this paper, we test whether map-derived indicators of landscape structure from the Norwegian monitoring programme for agricultural landscapes are correlated with visual landscape preferences. Two groups of people participated: (1) locals and (2) non-local students.Using the total dataset, we found significant positive correlations between preferences and spatial metrics, including number of land types, number of patches and land type diversity. In addition, preference scores were high where water was present within the mapped image area, even if the water itself was not visible in the images.When the dataset was split into two groups, we found no significant correlation between the preference scores of the students and locals. Whilst the student group preferred images portraying diverse and heterogeneous landscapes, neither diversity nor heterogeneity was correlated with the preference scores of the locals.We conclude that certain indicators based on spatial structure also have relevance in relation to landscape preferences in agricultural landscapes. However, the finding that different groups of people prefer different types of landscape underlines the need for care when interpreting indicator values
Authors
Svein SolbergAbstract
Remote sensing is a promising tool for monitoring forest health. Foliar mass, or correspondingly leaf area index (LAI), together with chlorophyll concentration in the foliage, are two suitable measures of forest health. So far, airborne laser scanning has proven to be very suitable for measuring LAI. The work is in progress, and still in an early phase.
Abstract
The paper describes the development of the two involved nurseries and the reforestation efforts and results on the two experimental sites at Munda and in Mahamaya
Authors
Torstein KvammeAbstract
No abstract has been registered
Authors
Risto Kasanen Jarkko Hantula Timo Kurkela Martti Vuorinen Antti Komualinen Johanna Haapala Henna Penttinen Egbert BeukerAbstract
No abstract has been registered
Authors
Anders Busse Nielsen Jasper Schipperijn Yngve Rosenblad Heldur Sander Mikk Sarv Kirsi Mäkinen Janis Donis Vegard Gundersen Ulrika Åkerlund Roland GustavssonAbstract
No abstract has been registered
Authors
Toril Drabløs EldhusetAbstract
No abstract has been registered