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
Abstract
No abstract has been registered
Authors
Sekhar Udaya NagothuEditors
Kathrine Torday GuldenAbstract
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Abstract
Use of genetic materials with a more “southern growth rhythm” has been suggested as one of the measures for adapting our forests to climate change. However, studies on Norway spruce (Picea abies (L.) Karst) provenances and families have shown a possible relationship between phenology (apical growth rhythm) and cambial growth rhythm that might have negative effects on latewood proportion and wood density. We made a detailed study of the xylem formation of four clones during one growth season. The clones were known to express contrasting phenology in terms of timing of bud flush equivalent to two weeks when assessed in 1997. Micro cores from four 20 year old ramets of the four clones, 16 trees in total, were sampled once a week from May to October in 2010. When bud flush were assessed in 2010 there were about one week difference between the most contrasting clones. Temperatures during the spring 2010 were low and flushing started in general late. No relationship was found between the clonal values for timing of bud flush and initiation of xylem formation. Large differences between clones in numbers of formed tracheids were found in later phases of the growing season. Both the rate of cell division and number of formed tracheids varied significantly between clones. Only small differences in latewood percentage were found between the clones. Genetic variation in xylem formation was found, but from this study the genetic variation in xylem formation seems to be independent from the genetic variation in phenology.
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Authors
Tatsiana EspevigAbstract
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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.