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.
2011
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Authors
Bernt-Håvard ØyenAbstract
Removal of up to 40-50 % of the total volume production by successive thinning from early age seems to have a positive effect on the yield of fresh wood in stands of Norway spruce. In young stands there is a decrease of yield caused by early, heavy thinning. The stands are usually stable and healthy. Low oriented and moderate thinning operations do not appear to influence the yield situation in general, although culmination is prolonged. Also in Central Norway difficult access to the forests, lack of roads, high labour costs and sometimes low initial densities moderate the present interest for thinning.
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Authors
Stig Strandli Gezelius Maria HauckAbstract
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Authors
Richard Fischer Wenche Aas W. De Vries Nicholas Clarke Pavel Cudlin David Leaver Lars Lundin Giorgio Matteucci Rainer Matyssek Teis Nørgaard Mikkelsen Michael Mirtl Yasemin Öztürk Dario Papale Nenad Potocic David Simpson Juha Pekka Tuovinen Timo Vesala Gerhard Wieser Elena PaolettiAbstract
Science-based approaches in addressing future risks and challenges for forests require close collaboration among the communities operating different monitoring and research networks as well as experts in process and large-scale modelling. Results of the COST FP0903 conference which took place in October 2010 in Rome, reveal valuable results from different European forest monitoring and research networks. However, the need for closer integration of these activities is obvious. In this paper, representatives from major European networks recommend a new approach for forest monitoring and research in Europe, based on a reasonable number of highly instrumented “supersites” and a larger number of intensive monitoring plots linked to these. This system needs to be built on existing infrastructures but requires increased coordination, harmonisation and a joint long term platform for data exchange and modelling.
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In recent years the harmonization of methods in the frame of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) operating under the UNECE Convention on Long-range Transboundary Air Pollution (CLRTAP) has been intensified. Among the C-actions of the FutMon project (LIFE07 ENV/D/000218; 2009-2010) the C1-Dep-22(SI) action was established with the goal to harmonize and develop the deposition monitoring procedures and sampling methods. The sampling equipment, spatial design of sampling plots and sampling frequency throughout Europe vary considerably. Therefore a step-by-step approach was made where the harmonized sampling equipment was developed and tested first. The selected collectors were installed at one observation plot of each participating country where measurements of throughfall and bulk deposition were run in parallel with the national collectors for a period of one year. To evaluate the agreement between methods, different statistical analyses were used including Altman-Bland plots, model II regression, and repeated measures ANOVA. Preliminary results from the “Intensive forest ecosystem monitoring plot” plot Brdo in NW Slovenia show a good agreement between national and harmonized bulk (both funnel-type) collectors, while comparison of throughfall measurements indicates systematic bias between harmonized (funnel-type) and national (gutter-type) collectors.
Abstract
Arable weeds are generally distributed in patches, while herbicides are applied uniformly. Herbicides can be saved if only the patches are sprayed, i.e. patch spraying (PS). Bottlenecks for cost-effective PS are weed monitoring technology and valid technology-based decision rules for PS (thresholds). The novel machine vision algorithm Weedcer has been developed as an efficient weed monitoring tool for PS. Weedcer estimates the proportions of young weed leaves and cereal leaves in high resolution red–green–blue images. We conducted field trials to test relative weed cover (RWC) and relative mayweed cover (RMC) estimated by Weedcer as decision rules for PS. RWC is the total weed cover divided by the total plant cover and RMC is the mayweed cover divided by the total plant cover. The main criterion for evaluation and basis of these thresholds was the measured grain yield. Images (about 0.06-m2) were acquired with a GPS guided autonomous field robot in spring, the normal time for spraying seed-propagated broadleaf weeds in both winter – and spring cereals in Norway. Three map-based trials (weed monitoring and spraying in two separate operations) showed that mean RWC per management unit (12.0 × 12.5-m) was generally adequate. In winter wheat heavily infested with scentless mayweed (Tripleurospermum inodorum (L.) Sch.Bip.) and/or scented mayweed (Matricaria recutita L.), the mean RMC per management unit was more adequate. Progress during the project allowed three additional trials conducted in real-time (weed monitoring and spraying in the same operation). These were conducted with the robot in spring cereals, and showed that a weighted moving average of RWC per image was adequate. The sprayed and unsprayed management units in these trials were minimum 3.0 × 3.0-m and 0.5 × 3.0-m, respectively. Results indicated that the Weedcer-based thresholds should be lower in wheat (Triticum aestivum) than in barley (Hordeum vulgare).
Editors
John Marshall Bryden Sophia Efstratoglou Tibor Ferenczi Tom Johnson Karlheinz Knickel Karen Refsgaard Kenneth J. ThomsonAbstract
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