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.
2010
Abstract
Understanding the feedback between terrestrial biosphere processes and meteorological drivers is crucial to ecosystem research as well as management. For example, remote sensing of the activity of vegetation in relation to environmental conditions provides an invaluable basis for investigating the spatiotemporal dynamics and patterns of variability. We investigate the Fraction of Absorbed Photosynthetically Active Radiation (fAPAR) using SeaWiFS satellite observations from 1998 to 2005 and ancillary meteorological variables from the CRU-PIK dataset. To what extent do precipitation and temperature dominate the terrestrial photosynthetic activity on monthly to interannual time scales? A spectral decomposition using Singular System Analysis leads to a global ‘classification’ of the terrestrial biosphere according to prevalent time-scale dependent dynamics of fAPAR and its relation to the meteorology. A complexity analysis and a combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients, separately for different time scales. Here, we differentiate between three time scales: on short time scales (compared to the annual cycle), variations in fAPAR coincide with corresponding precipitation dynamics. At the annual scale, which explains around 50% of the fAPAR variability as a global average, patterns largely resemble the biomes of the world as mapped by biogeographic methods.At longer time scales, spatially coherent patterns emerge which are induced by precipitation and temperature fluctuations combined. However, we can also identify regions where the variability of fAPAR on specific time scales cannot be traced back to climate and is apparently shaped by other geoecological or anthropogenic drivers. http://uregina.ca/prairies/assets/Prairie_Summit_Final_Program.pdf
Abstract
Determining the feedbacks between terrestrial biosphere processes and the meteorological drivers (here precipitation and temperature) is crucial to ecosystem research. In this context, the continuous monitoring of the earth surface provides an invaluable basis for investigating the spatiotemporal dynamics in the activity of vegetation in relation to environmental conditions. Here, we seek to identify which patterns of variability in the meteorological drivers dominate the terrestrial photosynthetic activity from monthly to interannual time scales (resp. fluctuation frequencies). We investigate the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) using SeaWiFS observations from 1998 to 2005 and ancillary meteorological variables. A spectralanalysis leads to a global `classification` of the terrestrial biosphere according to prevalent scale dependent dynamics of fAPAR and its relation to the meteorology. A combined subsignal extraction and dimensionality reduction reveals a series of dominant geographical gradients on specific time scales. E.g. we uncover spatially coherent patterns at low frequencies and show where these are induced by precipitation or temperature fluctuations. We also show where high frequency variations (relative to the annual cycle) in fAPAR coincide with corresponding precipitation dynamics. However, we can also identify regions where the variability of fAPAR on specific time scales cannot be traced back to climate and is apparently shaped by other geoecological or anthropogenic drivers. http://www.terrabites.net/fileadmin/user_upload/terrabites/PDFs/Programme_Book_TERRABITES.pdf
Authors
Peder GjerdrumAbstract
A number of presentations were given at the GlueLam Study Tour in Trøndelag arranged by The Norwegian Forest and Landscape Institute April 2010 within the Developing the Scots Pine Resource project. The editor wishes to express his gratitude to all those who contributed to the outcome of the study tour: To the host businesses, to the participants and those giving presentations, and to Northern Periphery Program for contributing to the funding. The presentations listed in this report has been collected, trimmed and otherwise slightly modified by the editor. However, the content as well as the layout have been the choice and responsibility of each author. The report is intended for publication in electronic format on the project\"s web page and distribution to the participants. However, the report is public and free to use for anybody, provided a proper citation is given.
Authors
Anette Edvardsen Rune Halvorsen Ann Norderhaug Oddvar Pedersen Knut RydgrenAbstract
Habitat specificity analysis provides a tool for partitioning landscape species diversity on landscape elements by separating patches with many rare specialist species from patches with the same number of species, all of which are common generalists and thus provide information of relevance to conservation goals at regional and national levels. Our analyses were based upon species data from 2201 patch elements in SE Norwegian modern agricultural landscapes. The context used for measuring habitat specificity strongly influences the results. In general the gamma diversity contribution and core habitat specificity calculated from the patch data set were correlated. High values for both measures were observed for woodland, pastures and road verges whereas midfield islets and boundary transitional types were ranked low, as opposed to findings in traditional, extensively managed agricultural landscapes. This is due to our study area representing intensively used agricultural landscape elements holding a more trivial species composition, in addition to ruderals being favoured by fertility and disturbance, a finding also being supported by the semi-natural affiliation index. Results obtained by use of checklist data from the same study area diverged from patch data. Caution is needed in interpretation of habitat specificity results obtained from checklist data, because modern agricultural landscapes contain several land types which are seldom surveyed by botanists, thus being under-represented in the data set. We propose the use of core habitat specificity and gamma diversity contribution in parallel to obtain a value neutral diversity assessment that addresses patch uniqueness and other properties of conservation interests.
Authors
Nicholas Clarke Milan Gryndler Hans-Holger Liste Reiner Schroll Peter Schröder Miroslav MatuchaAbstract
The halogens, most importantly fluorine, chlorine, bromine, and iodine, occur in nature as ions and compounds, including organic compounds. Halogenated organic substances (haloorganics) were long considered purely anthropogenic products; however, they are in addition a commonly occurring and important part of natural ecosystems. Natural haloorganics are produced largely by living organisms, although abiotic production occurs as well. A survey is given of processes of formation, transport, and degradation of haloorganics in temperate and boreal forests, predominantly in Europe. More work is necessary in order to understand the environmental impact of haloorganics in temperate and boreal forest soils. This includes both further research, especially to understand the key processes of formation and degradation of halogenated compounds, and monitoring of the substances in question in forest ecosystems. It is also important to understand the effect of various forest management techniques on haloorganics, as management can be used to produce desired effects.
Abstract
No abstract has been registered
Authors
Peder GjerdrumAbstract
This presentation describes the Conifer Heartwood rule, i.e. the constant difference between the square root of the cambial age and the number of heartwood rings. This difference seems to be an inherent property of each species, irrespective of stand or site characteristics, or for location in the tree. When needed, heartwood can be identified by means of IR ecposures or chemical indicators.
Authors
Carina E. Johansen Christian Lydersen Paul E. Aspholm tore Haug Kit M. KovacsAbstract
No abstract has been registered
Authors
Peder Gjerdrum Bjarne HamarAbstract
Commercial timber sawing is always done in trade-off between yield and capacity, between cost of raw material and of production. Accurate knowledge of the dimensions for every single log is needed for successful breakdown. Traditionally, mills sawing to customers\" order, i.e. timber lots of given dimension and quality, start the breakdown process by scaling and sorting unbarked logs. However, accuracy can be greatly improved if scaled after barking. Scaling barked logs to adapt sawing pattern to each log inevitably slows down production speed, and also produces a variety of sawn boards besides the ordered one. The goal of the project described in this paper was to optimise the yield while maintaining high capacity and sawing to order. A modern, medium-sized sawmill producing ca. 60 000 m3 spruce timber annually was about to renew the sawlog intake. A two-stage log scaling/sorting and sawing twin mini-series was concluded. The first stage is the traditional sorting of unbarked logs. In the new intake, when the order is to be produced, logs are debarked before a second scaling with a 3D scanner based on laser beams reflected from the smooth and bright log surface. Logs are directed to either of two log decks, or buffers, each of ca. 25 logs, and sawn in twin mini-series alternating between the two. Sorting criteria might be purely diameter, log length, quality prediction generated from log geometry, or a combination. The sawn timber yield was increased by up to 3 000 m3 annually, corresponding to the contribution margin improved by 3 mill. NOK or more. Production speed is increased by ca. 4%, but producing two orders simultaneously increases planning complexity, requiring additional training for involved personnel. It can be concluded that the chosen set-up: Two-stage log sorting with accurate scaling in the final sorting and sawing twin orders in alternating twin mini-series, has proved successful with respect to sawn timber recovery and production capacity.
Authors
Line Emilie Sverdrup Christine Bjørge Ole Martin Eklo Torsten Källqvist Ingeborg Klingen Marit Låg Edgar Rivedal Erik Ropstad Steinar Øvrebø Merete GrungAbstract
No abstract has been registered