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
Sarah Hale Marie Catharina Elmquist Rahel C Brändli Thomas Hartnik Lena Jakob Thomas Henriksen David Werner Gerard CornelissenAbstract
No abstract has been registered
Authors
Kjersti Aaby Sebastian Mazur Arnfinn Nes Grete SkredeAbstract
No abstract has been registered
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No abstract has been registered
Abstract
No abstract has been registered
Authors
Lena Jakob Thomas Hartnik Thomas Henriksen Marie Catharina Elmquist Rahel C Brändli Sarah Hale Gerard CornelissenAbstract
No abstract has been registered
Authors
Rune Andreassen Julia Schregel Alexander Kopatz Camilla Tobiassen Per Knappskog Snorre Hagen Oddmund Kleven Michael Schneider Ilpo Kojola Jouni Aspi Alexander M. Rykov Konstantin F. Tirronen Pjotr I. Danilov Hans Geir EikenAbstract
No abstract has been registered
Authors
J E Munyaneza V G Sengoda Leif Sundheim Richard MeadowAbstract
No abstract has been registered
Authors
Birgit Hafeld Borgen Ishita Ahuja Ole Petter Thangstad Bjørn Ivar Honne Jens Rohloff John Trevor Rossiter Atle M. BonesAbstract
This article will not be available due to copyright restrictions (c) 2012 by Wiley
Authors
Kyrre Linné Kausrud Bjørn Økland Olav Skarpaas Jean-Claude Grégoire Nadir Erbilgin Nils Christian StensethAbstract
In recent decades we have seen rapid and co-occurring changes in landscape structure, species distributions and even climate as consequences of human activity. Such changes affect the dynamics of the interaction between major forest pest species, such as bark beetles (Coleoptera: Curculionidae, Scolytinae), and their host trees. Normally breeding mostly in broken or severely stressed spruce; at high population densities some bark beetle species can colonise and kill healthy trees on scales ranging from single trees in a stand to multi-annual landscape-wide outbreaks. In Eurasia, the largest outbreaks are caused by the spruce bark beetle, Ips typographus (Linnaeus), which is common and shares a wide distribution with its main host, Norway spruce (Picea abies Karst.). A large literature is now available, from which this review aims to synthesize research relevant for the population dynamics of I. typographus and co-occurring species under changing conditions. We find that spruce bark beetle population dynamics tend to be metastable, but that mixed-species and age-heterogeneous forests with good site-matching tend to be less susceptible to large-scale outbreaks. While large accumulations of logs should be removed and/or debarked before the next swarming period, intensive removal of all coarse dead wood may be counterproductive, as it reduces the diversity of predators that in some areas may play a role in keeping I. typographus populations below the outbreak threshold, and sanitary logging frequently causes edge effects and root damage, reducing the resistance of remaining trees. It is very hard to predict the outcome of interspecific interactions due to invading beetle species or I. typographus establishing outside its current range, as they can be of varying sign and strength and may fluctuate depending on environmental factors and population phase. Most research indicates that beetle outbreaks will increase in frequency and magnitude as temperature, wind speed and precipitation variability increases, and that mitigating forestry practices should be adopted as soon as possible considering the time lags involved.
Authors
Jari Vauhkonen Liviu Theodor Ene Sandeep Gupta Johannes Heinzel Johan Holmgren Juho Pitkänen Svein Solberg Yunsheng Wang Holger Weinacker Marius Hauglin Vegard Lien Petteri Packalén Terje Gobakken Barbara Koch Erik Næsset Timo Tokola Matti MaltamoAbstract
Airborne laser scanning data and corresponding field data were acquired from boreal forests in Norway and Sweden, coniferous and broadleaved forests in Germany and tropical pulpwood plantations in Brazil. Treetop positions were extracted using six different algorithms developed in Finland, Germany, Norway and Sweden, and the accuracy of tree detection and height estimation was assessed. Furthermore, the weaknesses and strengths of the methods under different types of forest were analyzed. The results showed that forest structure strongly affected the performance of all algorithms. Particularly, the success of tree detection was found to be dependent on tree density and clustering. The differences in performance between methods were more pronounced for tree detection than for height estimation. The algorithms showed a slightly better performance in the conditions for which they were developed, while some could be adapted by different parameterization according to training with local data. The results of this study may help guiding the choice of method under different forest types and may be of great value for future refinement of the single-tree detection algorithms.