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
Authors
Ylva-li Blanck Juan Gowda Linda-Maria Mårtensson Jakob Sandberg Ann-Mari FranssonAbstract
The aim of this study was to ascertain whether there is a relationship between plant species richness and plant-available N, P and water in an environment subject to little anthropogenic disturbance. To accomplish this we studied the vegetation in matorral shrub-lands in northern Patagonia, Argentina. Due to the variation in slope, precipitation and aspect between the sites water status was determined using the 12C/13C fraction, δ13C, to investigate whether this was a confounding factor. The numbers of herb, shrub, liana and tree species were determined at 20 sites along an estimated precipitation gradient. Leaf P and N content and the δ13C of Berberis buxifolia were determined, as well as the soil P and N content at the different sites. A negative correlation was found between species richness and Berberis buxifolia foliar P concentration (52% of the species richness variation was accounted for), and a positive correlation was found between plant species richness and Berberis buxifolia foliar N: P ratios (54% of the species richness variation was accounted for). The relationship between species richness and foliar P was seen when all layers of vegetation were included (trees, lianas, shrubs and herbs). Foliar N showed no correlation with species richness, while soil extractable NH4 showed a weak positive correlation with the number of shrub layer species (lianas, shrubs and trees). The species richness of the shrub layer increased with decreasing values of δ13C. Low soil P availability thus affects local species richness in the matorral shrub-lands of Patagonia in Argentina although the growth of vegetation in the area has been shown to be limited by N. We suggest that low P levels increase plant species richness because low soil P concentration is associated with a high P partitioning and high potential for niche separation.
Authors
Karl Hilding Thunes Fred Midtgaard Lawrence R. Kirkendall Oscar Leveron Vicente EspinoAbstract
Next to expansion of agricultural land and natural disasters, forest fires, illegal logging and bark beetles constitute the largest threat to the pine forests of Central America. Every year, 80-100.000 ha disappears due to the combined activity of the three factors. Natural disasters such as hurricanes and droughts, as well as poor forest management and wildfires lead to a stressed forest which in turn is advantageous for the increase in bark beetle population levels. Epidemic population levels of attacking beetles are able to kill large quantities of forests within weeks. Moreover, dead wood material acts as fuel for wildfires that have escaped control. We propose a monitoring and control regime which aims holistically and directly to the root causes of wildfires, bark beetle outbreaks and subsequent illegal logging in the pine forests of Central America. Monitoring activities focus on community participation and communication, while control of bark beetles is a combination of both long-term sustainable forest management procedures as well as direct and non-destructive control measures of the beetles to reduce their population levels to an endemic level.
Authors
Peder GjerdrumAbstract
Grain angle was observed on 178 discs equally spaced along each of 24 mostly quite large spruce stems, and a general model estimated for grain angle variation along the radial distance from pith. Due to the three-dimensional approach and the large-size stems, new variability was identified, as compared to traditional two-dimensional approach applied on moderate-sized stem discs. The model standard error was 2.3º; half of this variation can be attributed to combined stem and disc effects, and half to purely random variation. Standard error for the model estimated for individual discs was 1.6 º. Observed against the stem centroid, pith angle varies randomly with average close to zero and standard deviation 2.2º. The results should be applicable for wood quality modelling and for commercial sawn timber production.
Authors
Halvor Solheim Martti VuorinenAbstract
During a survey conducted in August 2009 in northern Norway, symptoms typical for red band needle blight (1) were observed in four young Scots pine (Pinus sylvestris) stands. The stands, less than 15 years old, were located in humid sites near rivers in Bardu and Målselv municipalities, Troms County. Many of the oldest needles (2- to 3- years-old) in the lower part of young trees were partially or completely brown, but still attached, and red bands could be observed. Aggregations of conidial stromata were often seen in the red bands. Conidia were hyaline, smooth, thin walled, and filiform, 1.9 to 2.6 μm wide and 12 to 36 μm long....
Authors
Tore Filbakk Raida Jirjis Juha Nurmi Olav Albert HøibøAbstract
Increased use of pellets has resulted in a shortage of the traditional raw materials required for pellet making, including saw dust, shavings and cuttings from saw mills. Therefore, the pellets industry has started to look for alternative raw materials. Limited consumption of pulpwood from Scots pine (Pinus sylvestris L.) in Norway has made it a potential raw material for the pellets industry. A study on how bark content affects the quality of pellets is reported in this paper. Pellets from pinewood containing zero, five, 10, 30 and 100 percent bark were produced, and their quality parameters were evaluated. Combustion tests were also performed on the produced pellets. Pellets made from pure bark had the best mechanical properties compared with pellets made of wood containing various concentrations of bark. The differences were not substantial and the durability for all chosen assortments was in the same quality class in the CEN standard. A positive effect off the amount of steam added was found. The bulk densities of the blend pellets were higher than those of pure wood and bark. The ash content increased with the amount of bark in the pellets. There were no problems with sintering when the bark content was low (five and 10 percent). For pure bark pellets some sintering was registered.
Abstract
Timber constructions are often built in combination with other materials such as concrete. These materials can influence the timber construction. Moist concrete can e.g. lead to development of molds which creates an unhealthy living area for people. Furthermore, moisture in wood buildings can negatively affect the wood material, which can lead to negative biological activity in timber and possible reduction of strength properties of timber constructions. The present paper introduces a new innovative method of timber protection and describes the influence of moisture on wood and concrete. The new environmental friendly system for protection of timber has been tested on wood destroying fungi and termites. It can be shown that wood protection by means of electro osmotic pulsing technology can preserve wood in laboratory trials. The wood moisture content is reduced when the protection system is installed. Trials on protected wood against subterranean termites showed lower wood moisture content after test of protected samples compared to untreated samples. However, termite activity could not be reduced to a larger extend as the termite living surroundings were not included. It could be shown that humidity in pores of concrete in cellar walls is reduced using electro osmotic pulsing. The drying of concrete when combined with timber constructions can additionally help to reduce timber degradation as all protection measures that lead to a drier building are positive for fungi and subterranean termite control.
Authors
Vilnis Skipars Mari Kjos Baiba Krivmane Nina Elisabeth Nagy Ilze Gaile Danis Rungis Carl Gunnar FossdalAbstract
In Latvia and other Nordic countries Scots pine (Pinus sylvestris L.) is an economically important tree species, and the losses incurred by Heterobasidion annosum, a fungi that causes root rot in pines, are significant. Here we present results about candidate resistance gene expression using laser captured samples from different tissue types of one year old Scots pine saplings. Results show increase of expression of thaumatin-like protein (TLP) gene and pinosylvin synthase (PsBBs) gene one day after wounding or artificial inoculation of the saplings. Expression was analysed using the relative absolute quantification method of real-time PCR.
Abstract
We used two datasets of 14C analyses of archived soil samples to study carbon turnover in O horizons from spruce dominated old-growth stands on well-drained podsols in Scandinavia. The main data set was obtained from archived samples from the National Forest Soil Inventory in Sweden and represents a climatic gradient in temperature. Composite samples from 1966, 1972, 1983 and 2000 from four different regions in a latitude gradient ranging from 57 to 67oN were analysed for 14C content. Along this gradient the C stock in the O horizon ranges from 2.1 kg m-2 in the north to 3.7 kg m-2 in the southwest. The other data set contains 14C analyses from 1986, 1987, 1991, 1996 and 2004 from the O horizons in Birkenes, Norway. Mean residence times (MRT) were calculated using a two compartment model, with a litter decomposition compartment using mass loss data from the literature for the three first years of decomposition and a humus decomposition compartment with a fitted constant turnover rate. We hypothesized that the climatic gradient would result in different C turnover in different parts of the country between northern and southern Sweden. The use of archived soil samples was very valuable for constraining the MRT calculations, which showed that there were differences between the regions. Longest MRT was found in the northernmost region (41 years), with decreasing residence times through the middle (36 years) and central Sweden (28 years), then again increasing in the southwestern region (40 years). The size of the soil organic carbon (SOC) pool in the O horizon was mainly related to differences in litter input and to a lesser degree to MRT. Because N deposition leads both to larger litter input and to longer MRT, we suggest that N deposition contributes significantly to the latitudinal SOC gradient in Scandinavia, with approximately twice as much SOC in the O horizon in the south compared to the north. The data from Birkenes was in good agreement with the Swedish dataset with MRT estimated to 34 years.
Authors
Trygve D. Kjellsen Igor A. Yakovlev Carl Gunnar Fossdal Richard StrimbeckAbstract
Siberian spruce (Picea obovata) grows in the coldest forested environments on Earth, with average temperatures in midwinter months below -40 C and record lows below 60 C. Fully acclimated needles of this species survive immersion in liquid nitrogen at -196 C provided they are first cooled to an intermediate temperature of around -30 C. To investigate the role of dehydrins in extreme frost tolerance, we monitored frost tolerance, relative dehydrin concentration, and relative changes in dehydrin transcript levels in P. obovata needles over a full acclimation-deacclimation cycle.
Authors
Peder GjerdrumAbstract
This case study describes reflection, analyses and results obtained from investing in a new saw intake plant with the option to separate pre-sorted logs groups in two sub-sets for increased yield and sawing mini-series of 20-30 logs to maintain high capacity. The new plant was in need of careful trimming and follow-up during a period half a year or more before optimal operation was obtained. Log separation is done based on 3D scaling after debarking. As expected, scaling accuracy was substantially improved. However, scars and damages from the debarker cause some variation in the scaling, and most for 3-dimensional parameters like sweep and taper. Nevertheless, total sawn timber recovery increased by two percent of consumed log volume, equivalent to 2.3 % improvement in the sawmill\"s added value. Sawing two orders simultaneously increased the complexity of planning and sawn timber logistics. Automated sawn timber quality prediction based on observations of barked logs in the 3D scanner has so far not proved successful; one reason for this might be the quality variation within each log. It was concluded that the investment has proven profitable.