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.
2008
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We investigated whether the stand age affects the life span of tree and understory fine roots (<1mm) in three Norway spruce (Picea abies) stands: 30, 60 and 120-yr-old. In each stand 9 minirhizotrons were installed and images were collected once in a month throughout the growing season during the three years. Norway spruce fine roots in the 30-yr old stand had a life span 401 ± 27 and 341 ± 68 days, and understory 409 ± 162 and 349 ± 142 days, estimated by using the Kaplan Meier survival analysis (KM) and Weibull distribution, respectively...
2007
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We present results from early tests and field trials of offspring from two Norway spruce (Picea abies (L.) Karst.) seed orchards containing clones that have been transferred from high altitudes to sea level and from northern to southern latitudes. Seedlings from seeds produced in the low-altitude seed orchard developed frost hardiness later at the end of the growth season, flushed later in field trials, and grew taller than seedlings from seeds produced in natural stands. They had the lowest mortality rate and the lowest frequency of injuries in the field trials. Similar results were observed in seedlings from seeds produced in the southern seed orchard. We found no adverse effects of the changed growth rhythm. Seedlings from two seed crops in the southern orchard, produced in years with a warm and a cold summer, had different annual growth rhythms. The results are explained mainly by the effects of the climatic conditions during the reproductive phase. Seed crops from different years in the same seed orchard may produce seedlings that perform as if they were from different provenances. It is argued that the effects of the climatic conditions during seed production must contribute to the variation among provenances of Norway spruce.
Abstract
Genetic- and environmental variation and correlation patterns were characterized for modulus of elasticity (MOE), modulus of rupture (MOR) and related wood traits: latewood proportion, wood density, spiral grain, microfibril angle and lignin content in five full-sib families of Norway spruce.The families were evaluated on the basis of clearwood specimens from the juvenile -mature wood transition zone of 93 sampled trees at age 30 year from seed. Family-means varied significantly (p 0.05) for all wood traits studied except lignin content. MOE varied between 7.9-14.1 GPa among trees and 9.4-11.0 GPa among families. MOR varied between 47-87 MPa among trees and 61-71 MPa among families.Families remained significantly different in an analysis of specific MOE (MOE/density) and MOR (MOR/density). Hence, solely relying on wood density as a wood quality trait in tree breeding would not fully yield the potential genetic gain for MOE and MOR. Correlations between wood structural traits and specific MOE and MOR are presented and discussed.
Abstract
After two decades of monitoring forest health in Europe, in response to concern for negative effects of air pollution, a similar worry is now increasing in China. In a co-operative project between Chinese and Norwegian researchers a forest monitoring was implemented in the acid rain region in south China. During 2000–2004 two small watersheds were monitored: TieShanPing (TSP) near ChongQing City and LuChongGuan (LCG) near GuiYang City. They are covered by Masson pine (Pinus massoniana) forest. The methodology of the European intensive forest monitoring programme (ICP-Forests level-II) was adopted; including crown assessments, foliar chemistry, air and soil chemistry, and more. This paper presents results of this co-operative project. Considerable forest damage was revealed by monitoring the crown condition of Masson pine trees. The average defoliation percentage for all assessed trees (predominant, dominant and co-dominant pines, corresponding to Kraft classes 1–3) in the more acidified TSP was over 40% and remained stable throughout the monitoring period, accompanied by an extremely high mortality in some years. In contrast, the defoliation in the less acidified LCG was relatively low but increased considerably, from 16% to around 40%, within the 4 monitoring years. The significance of air pollution for the forest damage remains uncertain. The annual SO2 concentration in TSP and LCG is about 2 and 4 times higher than the critical level of 20 μg m−3 given in the LRTAP convention for effects on forests. Therefore the air pollution effects cannot be ruled out as contributing factors for forest damage. However, this cannot be substantiated based on the presented monitoring data since none of the specific symptoms of air pollution damage were observed. Furthermore, an analysis of the monitoring data did not reveal any significant correlation between defoliation and the soil chemical properties. It is noteworthy that the evident agents that were identified are capable of causing the observed forest damage. These agents were insect attacks and climatic stress. It is possible that the forest damage has complex causes.
Authors
John Derome Per Arild Aarrestad Paul Aspholm Vegar Bakkestuen Jarle Werner Bjerke Kjell Einar Erikstad Minna Hartikainen Ludmila Isaeva Martti Lindgren Antti-Jussi Lindroos Tor Myking Jarmo Poikolainen Pasi Rautio Ingvald Røsberg Maija Salemaa Hans Tømmervik Natalya VassilievaAbstract
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Authors
Tore SkrøppaAbstract
No abstract has been registered
Authors
Tore SkrøppaAbstract
No abstract has been registered