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.
2013
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Authors
Ivano Brunner Isabella Børja Lise Dalsgaard Gaby Deckmyn Alf Ekblad Douglas L. Godbold Irene Guerra Avalos Martin Lukac Karsten Kalbitz Kaie Kriiska Ivika Ostonen Andrea Schnepf Primož Simončič Elena VanguelovaAbstract
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Fruit-set involves a series of physiological and morphological changes that are well described for tomato and Arabidopsis, but largely unknown for sweet pepper (Capsicum annuum). The aim of this paper is to investigate whether mechanisms of fruit-set observed in Arabidopsis and tomato are also applicable to C. annuum. To do this, we accurately timed the physiological and morphological changes in a post-pollinated and un-pollinated ovary. A vascular connection between ovule and replum was observed in fertilized ovaries that undergo fruit development, and this connection was absent in unfertilized ovaries that abort. This indicates that vascular connection between ovule and replum is an early indicator for successful fruit development after pollination and fertilization. Evaluation of histological changes in the carpel of a fertilized and unfertilized ovary indicated that increase in cell number and cell diameter both contribute to early fruit growth. Cell division contributes more during early fruit growth while cell expansion contributes more at later stages of fruit growth in C. annuum. The simultaneous occurrence of a peak in auxin concentration and a strong increase in cell diameter in the carpel of seeded fruits suggest that indole-3-acetic acid stimulates a major increase in cell diameter at later stages of fruit growth. The series of physiological and morphological events observed during fruit-set in C. annuum are similar to what has been reported for tomato and Arabidopsis. This indicates that tomato and Arabidopsis are suitable model plants to understand details of fruit-set mechanisms in C. annuum.
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Terrestrial lidar (TLS) is an emerging technology for deriving forest attributes, including conventional inventory and canopy characterizations. However, little is known about the influence of scanner specifications on derived forest parameters. We compared two TLS systems at two sites in British Columbia. Common scanning benchmarks and identical algorithms were used to obtain estimates of tree diameter, position, and canopy characteristics. Visualization of range images and point clouds showed clear differences, even though both scanners were relatively high-resolution instruments. These translated into quantifiable differences in impulse penetration, characterization of stems and crowns far from the scan location, and gap fraction. Differences between scanners in estimates of effective plant area index were greater than differences between sites. Both scanners provided a detailed digital model of forest structure, and gross structural characterizations (including crown dimensions and position) were relatively robust; but comparison of canopy density metrics may require consideration of scanner attributes.
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Authors
Bjørn Arild Hatteland Solveig Haukeland Steffen Roth May Bente Brurberg Ian P. Vaughan William O. C. SymondsonAbstract
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Nondetection of trees is a serious problem for the use of terrestrial laser scanning (TLS) in forest inventory applications. The use of multiple coregistered scans can reduce nondetection but may not eliminate it, and it carries substantial field and post-processing costs. We examined and extended previously developed theoretical approaches to modeling nondetection. The results suggested that tree size as well as multiple stand structural characteristics may be factors, but the theoretical models do not lend themselves to empirical estimation. We then used distance sampling techniques to identify detection probabilities and develop adjusted estimates for trees per hectare and basal area in nine forest stands in southern Norway. The results compared favorably with field estimates based on fixed-area plots. The estimated detection probabilities indicate that correction for nondetection is needed unless the search for trees is limited to very small distances from the scanner. Distance sampling appears promising when TLS is used in the context of temporary-plot forest inventories.
Authors
Ragnar Johnson Mika Mustonen Tomas Lundmark Annika Nordin Yuri Gerasimov Aksel Granhus Eugene Hendrick Jari Hyninen Vivian Kvist Johannesen Adam Kaliszewski Virginijus Miksis Thomas Nord-Larsen Heino Polley Liana Sadauskiene Pat Snowdon Birger Solberg Erik Sollander Arnor Snorrason Mati Valgepea Sheila Ward Toms ZalitisAbstract
Forests will play a crucial role in the transformation from an economy based on fossil fuels to one relying on renewable resources. Hence, besides being a source of raw material for the forest industry, in the future, forests are expected to increasingly contribute to the production of energy as well as providing a wide range of environmental and social services. Thus, the objective of the present study is to assess the short-term and long-term potential for increasing sustainable wood supply in the EFINORD countries. Present practices and prospects for intensive forest management have been assessed using information from a questionnaire complemented by compilation and evaluating of national forest inventory (NFI) data and other forest sector relevant information. The study indicates a striking variation in the intensity of utilisation of the wood resources within the EFINORD region. For the region as a whole, there seems to be a substantial unused (biophysical) potential. However, recent NFI data from some countries indicate that annual felling rates can be underestimated. If felling rates are higher than currently recognised then, given the increased demand for wood-based energy, there appears to be a need to discuss strategies for large-scale implementation of more intensive forestry practices to ensure that the availability of wood resources in the future can meet an increasing demand in the EFINORD countries.