| 1. |
- Berglund, Håkan
(författare)
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Spatial distribution of dead wood and the occurrence of five saproxylic fungi in old-growth timberline spruce forests in northern Finland
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 527-540
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Tidskriftsartikel (refereegranskat)abstract
- Adequate understanding of the factors that determine the establishment and survival of dead-wood-dependent species in natural forests is a prerequisite to the successful maintenance of these species in managed forests. This study investigated the factors affecting the occurrence of five wood-inhabiting polypores in old-growth timberline spruce forests in northern Finland, including the substrate availability and the spatial arrangement of large-diameter logs. The volume of coarse woody debris (CWD) varied significantly between the sites (range 15-30 m3 ha-1), large-diameter logs comprising on average 35% of the total CWD volume. However, the within-site variation in CWD volume was 10-15 times larger than the between-site variation. The spatial distribution of large-diameter logs was aggregated or initially aggregated on four sites and random on one site, creating local patches of high CWD volume. An individual target species occurred on average on 8% of all large-diameter logs, and on 11% of optimal logs (as determined by the decay stage). The characteristics of the logs and stand variables explained partly the occurrence of the target species; furthermore, the mortality pattern of trees (stem breakage versus uprooting) and the presence of primary decomposers also significantly affected the occurrence of the target species. The results indicate that besides substrate availability and quality, local habitat factors and species interactions also play a role in the occurrence of wood-inhabiting fungi in boreal timberline forests.
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| 2. |
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| 3. |
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| 4. |
- Birkedal, Maria, et al.
(författare)
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Rodent impact on establishment of direct-seeded Fagus sylvatica, Quercus robur and Quercus petraea on forest land
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 298-307
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Tidskriftsartikel (refereegranskat)abstract
- Seed predation by granivorous rodents constitutes a major problem during reforestation using direct seeding. Acorns or beech nuts were sown at 14 different sites in Denmark and southern Sweden, and seedling establishment was inventoried during the first three growing seasons. Around the time of sowing, rodents were either snap-trapped or live-trapped. At some sites, perches for raptors were installed, and at other sites, signs of predation were investigated or predation was monitored by camera surveillance. Granivorous rodents had a profound negative influence on sowings, and the removal of beech nuts occurred rapidly following sowing. Establishment of oak was better when surroundings consisted of mixed forests rather than broadleaved forests. Fewer rodents were caught, and establishment was better, in large reforestation areas. Rodent captures indicated that forest edges, slash piles and stone wall remains were suitable rodent microhabitats. Snap-trapping or raptor perches did not result in increased oak establishment. Neither sowing in summer nor increased seeding depth decreased predation by rodents on beech nuts. In conclusion, seeds need protection from rodents immediately at the time of sowing. Choosing large regeneration areas combined with removal of suitable rodent habitats seems to be a practical alternative for the development of successful strategies for direct seeding.
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| 5. |
- Brännström, Mattias, et al.
(författare)
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Predicting board strength by X-ray scanning of logs : the impact of different measurement concepts
- 2007
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 22:1, s. 60-70
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to compare the individual board strength predictions from an X-ray log scanner by using either two or four X-ray directions. The benefit of applying traceability between log and board was also studied. In total, 119 Norway spruce [Picea abies (L.) Karst.] sawlogs were scanned by an X-ray log scanner at the log sorting station of a sawmill and sawn into two centre pieces per log. Individual board traceability was enabled by following the rotational position of the log in the scanner and at the succeeding sawing. All boards were graded by a commercial strength grading machine before destructive testing was done. The resulting data were used to derive variables for building multivariate partial least squares strength prediction models. In the modelling a hierarchical modelling approach was used, where annual ring width, dry density and elasticity were also modelled. For all concepts studied the models' fit was similar. Only minor benefits could be found when using four directions and traceability compared with two directions and no traceability. One conclusion is that the result for traceability, from four directions in particular, is more sensitive for the interior knot reconstruction result. The strength prediction was on the same R2 level as for the strength grading machine
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| 6. |
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| 7. |
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| 8. |
- Danielsson, Marie, et al.
(författare)
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Mini-seedlings of Picea abies are less attacked by Hylobius abietis than conventional ones : Is plant chemistry the explanation?
- 2008
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 23:4, s. 299-306
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Tidskriftsartikel (refereegranskat)abstract
- The pine weevil, Hylobius abietis (L.), is a major pest in conifer reforestation areas in the Palaearctic region. Size and chemistry of the seedlings may explain the damage rates in plantations. The performance of 10-week containerized seedlings (mini-seedlings) was compared with 1-year-old conventional seedlings of Norway spruce, Picea abies (L.), in a field experiment in central Sweden. After 2 years the weevil damage was lower for the mini-seedlings than for the conventional seedlings (3.5 vs 55%). After 3 years, the overall survival was 82 and 75%, respectively. Weevil damage was the main cause of mortality for conventional seedlings, whereas mini-seedlings mainly died from drought. Volatiles of the two seedling types were compared by solid-phase microextraction-gas chromatography -mass spectrometry (SPME-GC-MS). Unwounded mini-seedlings and conventional seedlings differed in their compositions of monoterpenes and sesquiterpenes. Miniseedlings mainly emitted limonene, known to be repellent to the pine weevil. When wounded, green leaf volatiles were released by mini-seedlings while the pine weevil attractant alpha-pinene was released by conventional seedlings. Volatiles may partly explain the mini-seedlings' resistance against weevil attack. Further studies are needed to clarify how long this miniseedling effect remains.
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| 9. |
- Gräns, Daniel, et al.
(författare)
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Genetic variation and relationships to growth traits for microfibril angle, wood density and modulus of elasticity in a Picea abies clonal trial in southern Sweden
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24:6, s. 494-503
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variation in wood density, microfibril angle (MFA), wood stiffness (MOE), height, diameter and volume was investigated in a 26-year-old Norway spruce [(Picea abies (L.) Karst.] clonal trial in southern Sweden. Wood quality measurements were performed on 10 mm increment cores using SilviScan. For MFA, mean values of annual rings showed the highest value (30°) at ring 2 counting from the pith, followed by a steep decrease and a gradual stabilization around ring 12 at approximately 14°. MOE showed a monotonic increase from 5 GPa to 14 GPa when moving from pith to bark. High broad-sense heritability values were found for wood density (0.48), MFA (0.41) and MOE (0.50). All growth traits displayed heritability values of similar magnitudes as reported in earlier studies. The generally high age-age correlations between different sections of the wood cores suggested that early selection for wood quality traits would be successful. Owing to unfavorable genetic correlations between volume and MOE, the correlated response indicated that selection for volume only at age 10 would result in a 0.27% decrease in weighted MOE at age 26 for every 1% increase in volume.
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| 10. |
- Götmark, Frank, 1955, et al.
(författare)
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Browsing damage on broadleaved trees in semi-natural temperate forest in Sweden, with a focus on oak regeneration
- 2005
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 20:3, s. 223-234
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Tidskriftsartikel (refereegranskat)abstract
- Absence of, or poor, oak (Quercus spp.) regeneration is a problem in uneven-aged, mixed closed-canopy broadleaved forests. Browsing by ungulates on small trees may contribute to poor oak regeneration in such forests. This possibility was investigated in 25 Swedish stands, and browsing damage was analysed in relation to landscape and stand factors. The proportion of browsed small (<20 cm tall) oak seedlings and other seedlings was low, and apparently a minor mortality factor. For saplings (20130 cm tall), accumulated browsing damage was generally higher on oak than on five major competing tree species: Fraxinusexcelsior, Corylusavellana, Tiliacordata, Acerplatanoides and Sorbusaucuparia. Leaf removal was rare in late summer, except for rowan. The amount of cover (shelter) for ungulates near plots was positively correlated with oak browsing intensity; within plots, a high density of ash saplings may reduce browsing on oak saplings. In these forests, browsing probably retards growth of oak saplings relative to competing trees. Oak may persist as a minor stand component, but monitoring is needed to study future changes.
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| 11. |
- Högberg, Karl-Anders, et al.
(författare)
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Field performance of Pinus contorta trees propagated vegetatively via adventitious buds
- 2005
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 20:4, s. 318-321
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Tidskriftsartikel (refereegranskat)abstract
- Pinus contorta plants regenerated from adventitious buds induced on zygotic embryos were planted in a field trial where growth, straightness and flowering were followed over 7 years. Seedlings were taller than the plants derived from adventitious buds at the start of the field trial. Adventitious plants did not catch up with seedlings in height after 7 years in the field, but the relative height growth was equal. The higher frequency of plagiotropic growth that was displayed by adventitious plants the first year in the field was not reflected by differences in the frequency of basal sweeps 6 years later. However, the frequency of crooked stems was comparatively high but similar among the plant types. Flowering was more abundant for the seedlings than for adventitious plants. Taken together, the results show that P. contorta can be cloned via adventitious buds from zygotic embryos, and that the resulting plants show satisfactory growth for inclusion in breeding.
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| 12. |
- Karlman, Lars, et al.
(författare)
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Variation in spring and autumn frost tolerance among provenances of Russian larches (Larix Mill.)
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 100-110
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Tidskriftsartikel (refereegranskat)abstract
- Spring and autumn frost tolerance was measured using material from a range-wide (50-67 N, 38-158 E) provenance trial of four Russian larch species (Larix sukaczewii Dyl., L. sibirica Ledeb., L. gmelinii Rupr. and L. cajanderi Mayr.) growing in northern Sweden. Shoots were collected in early May and late September and frozen at -8, -12, -16 and -20C. Cambial damage was assessed visually after development under ideal conditions for 2 weeks. Differences in frost damage among provenances were highly significant in both spring and autumn. Autumn frost damage was significantly correlated with provenance latitude and longitude and spring frost damage was significantly correlated with provenance longitude but not latitude. Frost damage was not correlated with provenance elevation. North-western provenances showed the least damage and far-eastern provenances the greatest damage in both spring and autumn. A possible explanation for less spring frost damage to north-western provenances is adaptation to maritime conditions in proximity to the Barents Sea, which is often ice free in late winter. This would counteract early loss of frost tolerance and bud flushing if warm spells occurred in late winter. North-eastern Siberian provenances did not show similar adaptation and may exhibit increased spring frost damage if global warming eventually results in the Arctic Ocean north of Siberia becoming ice free in late winter.
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| 13. |
- Karlsson, Jenny, et al.
(författare)
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RoadOpt : a decision support system for road upgrading in forestry
- 2006
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 21:S7. 7, s. 5-15
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Tidskriftsartikel (refereegranskat)abstract
- Road blocking due to thawing or heavy rains annually contributes to a considerable loss of profit in Swedish forestry. Companies have to build large stocks of sawlogs and pulplogs to secure a continuous supply during periods where the accessibility of the road network is uncertain. This storage leads to quality deterioration, which means loss in profit. One approach to reduce the losses due to blocked roads is to upgrade the road network to a standard that guarantees accessibility throughout the year. This article describes a decision support system called RoadOpt for the planning of forest road upgrading. The planning horizon is about one decade. The system uses a Geographical Information System (GIS)-based map user interface to present and analyse data and results. Two important modules are the Swedish road database, which provides detailed information about the road network, and an optimization module consisting of a mixed integer linear programming model. A case study from a major Swedish company is presented.
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| 14. |
- Komonen, Atte
(författare)
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Forest characteristics and their variation along the lakeshore-upland ecotone
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 515-526
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Tidskriftsartikel (refereegranskat)abstract
- In forestry operations riparian buffer zones have been retained mainly to protect water quality. Because riparian forests are also important for maintaining terrestrial biodiversity, the associated ecotones need to be characterized and defined. Forest characteristics were studied along 50 m lakeshore-upland gradients in semi-natural forests in boreonemoral Sweden. Significant changes in the density of living and dead trees, as well as in their diameters, were recorded. The edge influence was generally discernible 10-30 m from the shoreline and was manifested in the very high density of understorey and midcanopy trees. The species-specific responses reflected the known shade and flooding tolerances of tree species. Most dead trees were standing, or broken from the roots or tree base; relatively few uprooted trees were recorded, suggesting that wind is only a moderate mortality factor. In comparison with the literature, the studied lakeshore forests are distinct from managed and set-aside upland forests in terms of tree species composition and woody debris characteristics; they thus contribute to landscape heterogeneity. If buffer zones along lakes were designed so that they captured the entire riparian ecotone, this would increase their contribution to the conservation of terrestrial biodiversity.
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| 15. |
- Lundmark, Robert
(författare)
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Cost structure of and the competition for forest-based biomass
- 2006
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 21:3, s. 272-280
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Tidskriftsartikel (refereegranskat)abstract
- Biomass has become a popular alternative to satisfy expanding energy demand and as a substitute for fossil fuels and phased-out nuclear energy in Europe. The European Union White Paper stipulates that the utilization of biomass shall increase to 1566 TWh by 2010. However it is often overlooked that the forest resources are already, to a large extent, used by the forest industries. When promoting biomass for energy generation the consequences for the forest industries also need to be considered. Sweden is an excellent case study, as there are vast quantities of forest resources, nuclear power is starting to be phased out, there are restrictions on expanding hydropower and the political desire exists to "set an example" with respect to carbon dioxide emissions. This paper attempts to estimate and analyse the supply of two types of forest resource, namely, roundwood and harvesting residues derived from final harvesting and commercial thinnings. Two separate supply curves are estimated: one forroundwood and one for harvesting residues. The cost structure is based on an economic-engineering approach where the separate cost components are constructed from the lowest cost element into aggregates for labour, capital, materials and overhead costs for each forest resource. The results indicate an unutilized economic supply of 12 TWh of harvesting residues in Sweden. However, after these 12 TWh have been recovered it becomes more profitable to use roundwood for energy purposes than to continue extracting further amounts of harvesting residues.
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| 16. |
- Lycken, Anders, et al.
(författare)
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A multivariate approach to automatic grading of Pinus sylvestris sawn timber
- 2006
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 21:2, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to create an easier way to handle the often complicated and intricate situations with which the operator of an automatic grading system is faced each time a change to the grading rules is proposed. The scope of the study was the possibility of a holistic method of automatic appearance grading of sawn wood similar to manual grading and based on multivariate statistics. The study was based on 90 Scots pine ( Pinus sylvestris L.) sawlogs. The logs were sawn and the boards were scanned and manually graded. The result of the manual grading was defined as the true grade. Models for prediction of board grade based on aggregated defect variables were calibrated using partial least squares regression. The classification based on the multivariate models resulted in 80-85% of the boards being correctly graded according to the manual grading. In conclusion, this paper shows that a multivariate statistical approach for grading timber is a possible way to simplify the process of grading and to customize the grading rules when using an automatic grading system
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| 17. |
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| 18. |
- Lygis, V., et al.
(författare)
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Wood-inhabiting fungi in stems of Fraxinus excelsior in declining ash stands of northern Lithuania, with particular reference to Armillaria cepistipes
- 2005
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 20:4, s. 337-346
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Tidskriftsartikel (refereegranskat)abstract
- Stem bases of 210 Fraxinus excelsior trees of three different health categories were sampled by the means of an increment borer in declining ash stands in northern Lithuania. From this number, 15 sound-looking, 132 declining and 63 dead trees from three discrete plots yielded 352 isolates, representing 75 fungal species. In addition, mycelial fans and rhizomorphs typical of Armillaria spp. from 205 and 20 trees, respectively, were sampled and subjected to fungal isolations. Species richness was similar in trees from each health category, but community structures differed, indicating that species composition of wood-inhabiting fungi in stems changes along with the changes in tree health condition. Armillaria cepistipes was the most common species ( 86 isolates from 210 wood samples, or 41.0%), isolated more frequently and consistently than any other potential tree pathogen. It also showed abundant occurrence on a majority of trees in the form of mycelial fans and rhizomorphs, from which 64 and 14 isolates of the fungus were obtained, respectively. The population structure of A. cepistipes revealed the presence of 53 - 93 genets per hectare, some of which extended up to 30 - 55 m.
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| 19. |
- Löf, Magnus
(författare)
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Adaptive forest management in central Europe: Climate change impacts, strategies and integrative concept
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 473-482
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Tidskriftsartikel (refereegranskat)abstract
- Climatic warming may lead to increased or decreased future forest productivity. However, more frequent heat waves, droughts and storms and accompanying pathogen attacks are also expected for Europe and are considered to be increasingly important abiotic and biotic stress factors for forests. Adaptive forestry can help forest ecosystems to adapt to these new conditions in order to achieve management goals, maintain desired forest ecosystem services and reduce the risks of forest degradation. With a focus on central Europe, this paper presents the following management strategies: (1) conservation of forest structures, (2) active adaptation, and (3) passive adaptation. The feasibility and criteria for application of the different strategies are discussed. Forest adaptation may entail the establishment of oneonativeo forests, including the use and intermixing of native and non-native tree species as well as non-local tree provenances that may adapt better to future climate conditions. An integrative adaptive management concept is proposed that combines (1) species suitability tests and modelling activities at the international scale, (2) priority mapping of adaptation strategies at the national to regional scale, and (3) implementation at the local scale. To achieve this, an international experimental trial system is required to test suitable adaptive measures throughout Europe and worldwide.
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| 20. |
- Löf, Magnus
(författare)
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Effects of roe deer browsing and site preparation on performance of planted broadleaved and conifer seedlings when using temporary fences
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 308-317
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Tidskriftsartikel (refereegranskat)abstract
- The effects of fencing and site preparation on performance of birch (Betula pendula Roth), oak (Quercus robur L.), pine (Pinus sylvestris L.) and spruce [Picea abies (L.) Karst.] seedlings were studied over four growing seasons in southern Sweden. The experiment was composed of four browsing treatments, from which roe deer (Capreolus capreolus L.) were excluded for 0, 12, 24 or 42 months, and four soil treatments. Natural browsing was combined with artificial browsing (clipping). It was demonstrated that browsing by roe deer could be isolated from browsing by moose (Alces alces L.) by selective fencing. Except for birch, browsing had little effect on seedling survival. Browsing reduced height growth by more than 100% for oak and pine, and more than 60% of pine seedling developed multiple stems. Except for oak, site preparation increased seedling survival. Inverting site preparation, in combination with or without fertilization, produced positive growth responses in seedlings, whereas patch scarification did not. There was no interaction between browsing and soil treatments on seedling performance. It was concluded that long-term protection against browsing by roe deer is needed for oak and pine, whereas short-term fences might be used for birch, and that spruce is relatively unaffected by browsing.
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| 21. |
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| 22. |
- Majdi, Hooshang, et al.
(författare)
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Root respiration data and minirhizotron observations conflict with root turnover estimates from sequential soil coring
- 2007
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 22:4, s. 299-303
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Tidskriftsartikel (refereegranskat)abstract
- The turnover of fine roots in northern coniferous forests has conventionally been assumed to be rapid, in line with results from sequential coring in the late 1970s in a Swedish Scots pine stand (SWECON project) where a rate of 7.4 year(-1) was estimated. New quantifications of the root respiration in other stands motivated a recalculation of the SWECON data; an indirect estimation of the turnover rate was much slower, about 2.1 year(-1). As a consequence, fine-root production is considered to be much lower than in previous estimates. Furthermore, direct observations of Norway spruce fine roots (< 1 mm) from minirhizotrons in Sweden, including a site close to the SWECON site, indicated a slower estimate, with fine-root turnover rate of 0.9 year
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| 23. |
- Månsson, Johan, et al.
(författare)
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Quantitative estimates of tree species selectivity by moose (Alces alces) in a forest landscape
- 2007
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 22:5, s. 407-414
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Tidskriftsartikel (refereegranskat)abstract
- An extensive literature is available on browsing preference for certain tree species. However, useful predictive tools for estimating the impact of deer on forests production and biodiversity can still be improved. A step in that direction is not only to rank preference among tree species but also to quantify the relative risk of being browsed. The foraging selectivity of moose was evaluated using three different statistical methods developed to study habitat utilization. The general pattern for the three methods was consistent. From the results, groups of forage species were clustered and a quantitative index of selectivity was calculated for the groups. The selectivity index showed that rowan (Sorbus aucuparia), willow (Salix ssp.) and aspen (Populus tremula) had a 14 times higher probability of being browsed than a group consisting of Scots pine (Pinus sylvestris) and downy birch (Betula pubescens), while juniper (Juniperus communis) and silver birch (Betula pendula) had a 3.5 times higher probability than Scots pine and downy birch. Since the most preferred species were the least abundant, one should be cautious about the generality of the index between areas, as it may indicate that preference depends on plant species composition. The method used can easily be applied in forest management. Information on quantitative selectivity indices may improve the possibility of managing moose in accordance with acceptable browsing damage.
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| 24. |
- Nittérus, Karolina, 1972, et al.
(författare)
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Commercial harvest of logging residue in clear-cuts affects the diversity and community composition of ground beetles (Coleoptera : Carabidae)
- 2007
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 22:3, s. 231-240
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Tidskriftsartikel (refereegranskat)abstract
- Structural complexity of the habitat is known to influence the diversity and abundance of arthropod populations. Earlier studies have shown that presence of logging residue ( slash) on the ground contributes to microhabitat complexity and removal of slash for biofuel in clear-cuts can have short-term ( similar to 1 year) effects on ground-active beetle populations. This study examines the consequences of slash removal on carabids (Coleoptera: Carabidae) 5-7 years after harvest. Sampling of beetles was done by pitfall trapping in three matched clear-cut pairs, in spruce forest in central Sweden. The number and diversity (Berger-Parker dominance index) of carabid species were significantly higher in clear-cuts with slash harvest than in sites where slash was left on the ground. No difference in the overall rank-abundance pattern was found between clear-cuts with different slash treatments, but for species with certain habitat preferences the community was significantly altered. In all clear-cuts, slash removal caused a shift in dominance with an increase in generalist species and a decline in forest species. The results show that removal of slash may have long-lasting effects on the carabid community composition and structure. Hence, in forest landscapes with large-scale biofuel harvest, generalist carabid species may increase their abundance. Following the precautionary principle, it is suggested that every fifth clear-cut should be free of slash harvest.
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| 25. |
- Oostra, Swantje, et al.
(författare)
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Impact of tree species on soil carbon stocks and soil acidity in southern Sweden
- 2006
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Ingår i: Scandinavian Journal of Forest Research. - 0282-7581 .- 1651-1891. ; 21:5, s. 364-371
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Tidskriftsartikel (refereegranskat)abstract
- The impact of tree species on soil carbon stocks and acidity in southern Sweden was studied in a non-replicated plantation with monocultures of 67-year-old ash (Fraxinus excelsior L.), beech ( Fagus silvatica L.), elm (Ulmus glabra Huds.), hornbeam (Carpinus betulus L.), Norway spruce ( Picea abies L.) and oak ( Quercus robur L.). The site was characterized by a cambisol on glacial till. Volume-determined soil samples were taken from the O-horizon and mineral soil layers to 20 cm. Soil organic carbon (SOC), total nitrogen (TN), pH (H2O), cation-exchange capacity and base saturation at pH 7 and exchangeable calcium, magnesium, potassium and sodium ions were analysed in the soil fraction < 2 mm. Root biomass (< 5 mm in diameter) and its proportion in the forest floor and mineral soil varied between tree species. There was a vertical gradient under all species, with the highest concentrations of SOC, TN and base cations in the O-horizon and the lowest in the 10 - 20 cm layer. The tree species differed with respect to SOC, TN and soil acidity in the O-horizon and mineral soil. For SOC and TN, the range in the O-horizon was spruce > hornbeam > oak > beech > ash > elm. The pH in the O-horizon ranged in the order elm > ash > hornbeam > beech > oak > spruce. In the mineral soil, SOC and TN ranged in the order elm > oak > ash = hornbeam > spruce > beech, i.e. partly reversed, and pH ranged in the same order as for the O-horizon. It is suggested that spruce is the best option for fertile sites in southern Sweden if the aim is a high carbon sequestration rate, whereas elm, ash and hornbeam are the best solutions if the aim is a low soil acidification rate.
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| 26. |
- Skog, Johan, et al.
(författare)
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Heartwood diameter measurements in Pinus sylvestris sawlogs combining X-ray and three-dimensional scanning
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24:1, s. 182-188
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Tidskriftsartikel (refereegranskat)abstract
- Quality sorting of sawlogs based on three-dimensional (3D) or X-ray scanning or a multivariate combination of variables from both methods may be used to decrease the production of off-grade products carrying unwanted combinations of dimension and grade. There is, however, potential for further improving the sorting accuracy if 3D and X-ray raw data are combined at an early stage using path length compensation. From the measured 3D shape, a good estimate of the length of each X-ray path through the log can be made, enabling the calculation of a log density profile from the measured X-ray attenuation. The effect of this technique on heartwood diameter measurements of 423 Scots pine (Pinus sylvestris L.) logs was evaluated. By the addition of 3D data to the X-ray data it was possible to raise the predictability of the heartwood diameter from R 2=0.84 to 0.95 and to improve the root mean square error from 17 mm to 9.3 mm, primarily because of the enhanced contrast between heartwood and sapwood.
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| 27. |
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| 28. |
- Stendahl, Matti
(författare)
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Management of product development projects in the wood industry
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 434-447
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Tidskriftsartikel (refereegranskat)abstract
- This study used data on project management from 70 recent product development projects in the wood industry. The objective was to test the influence of some project management factors, known from cross-industry research to be keys to product development project success, on product development project success in the context of the wood industry. Through the use of hierarchical multiple regression analysis, it was found that both the sharpness of the product concept definition and the strength of the project leader had significant positive influences on the success of product development projects. Conversely, product advantage, team cross-functionality and customer involvement did not have a significant positive influence on the success of these projects. The latter even indicated a negative influence on product development project success. Project uncertainty, as manifested in the degree of newness of the technology and the marketing strategies of the product to the innovating strategic business unit, did not influence the relationship between project management factors and product development project success. Some of die findings were unexpected and may be explained by the industry's unaccustomedness to customer co-operation and the fact that product development in the wood industry takes place within conventional technology and market bounds.
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| 29. |
- Valtinat, Karin, et al.
(författare)
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Restoration of oak forest: Effects of former arable land use on soil chemistry and herb layer vegetation
- 2008
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 23:6, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- Stands of pedunculate oak (Quercus robur) planted 50-80 years ago on two types of land (previously forested land and former arable fields) were compared regarding vegetation and soil. Former arable soils were characterized by a higher pH, higher nitrate concentration and higher soil density, but had lower organic matter content and lower ammonium concentration in the topsoil (0-5 cm). These differences, however, decreased with soil depth. Phosphorus concentration was consistently higher in former fields throughout the soil profile (0-45 cm). Nitrogen mineralization, determined by in situ incubation, showed a strong seasonal pattern with peak values in spring. Non-metric multidimensional scaling ordination revealed marked compositional differences in the vegetation between the two land-use categories, and also compositional turnover along gradients in soil pH and nitrogen availability. Differences in soil pH between land-use categories occurred in a range critical for the establishment of many typical forest herb layer species. Plant indicator species were identified for the two land-use categories. The results showed that acid-sensitive forest herbs may benefit from the higher pH soils in new woodlands, in contrast to ancient forest soils with little buffer capacity towards natural and anthropogenic acidification. In conclusion, former arable use has long-lasting effects on soil properties and vegetation composition in broadleaved forests. New woodlands on former fields can thus offer relatively persistent new habitats for acid-sensitive species that have suffered from reduction in habitat area during historic periods of deforestation and cultivation.
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| 30. |
- Von Arnold, Karin, et al.
(författare)
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Can distribution of trees explain variation in nitrous oxide fluxes?
- 2005
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 20:6, s. 481-489
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Tidskriftsartikel (refereegranskat)abstract
- The impact of distance to tree stems on nitrous oxide (N2O) fluxes was examined to determine whether it is possible to improve the accuracy of flux estimates from boreal forest soils. Dark static chambers were placed along transects between pairs of trees within a Norway spruce stand and fluxes of N2O and carbon dioxide (CO2) were measured during the period 1999-2003. The groundwater table was measured on every sampling occasion along the transects. In addition, radiation transmission, potential diffusion rate and biomass of forest floor vegetation were measured once at each chamber site along one of the transects and soil samples were collected at three depths, from which pH, denitrification enzyme activity, soil moisture, organic matter, and carbon and nitrogen content were determined. There was a high level of variation in the N2O fluxes, both spatially and temporally. However, the spatial variation in the N2O fluxes within the transect could not be explained by differences in any of the measured variables. Sometimes, mainly when no major peaks occurred, N2O fluxes were significantly correlated with CO2 release. It is concluded that distance to stems cannot be used to improve the design of sampling schemes or for extrapolating flux levels to larger scales.
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| 31. |
- von Arnold, Karin, et al.
(författare)
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Greenhouse gas fluxes from drained organic forestland in Sweden
- 2005
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 20:5, s. 400-411
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to estimate the contribution of drained organic forestlands in Sweden to the national greenhouse gas budget. Drained organic forestland in Sweden collectively comprises an estimated net sink for greenhouse gases of -5.0 Mt carbon dioxide (CO2) equivalents year(-1) ( range -12.0 to 1.2) when default emission factors provided by the Good practice guidance for land use, land-use change and forestry are used, and an estimated net source of 0.8 Mt CO2 equivalents year(-1) ( range -6.7 to 5.1) when available emission data for the climatic zones spanned by Sweden are used. This discrepancy is mainly due to differences in the emission factors for heterotrophic respiration. The main uncertainties in the estimates are related to carbon changes in the litter pool and releases of soil CO2 and nitrous oxide.
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| 32. |
- Wallrup, Emma, et al.
(författare)
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Deciduous trees affect small-scale floristic diversity and tree regeneration in conifer forests
- 2006
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 21:5, s. 399-404
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing interest in the effects of deciduous trees on biodiversity, soil processes and long-term productivity in boreal, conifer-dominated forests. This study investigated whether individual birch trees allowed to grow to maturity in the coniferous forest can have a local effect on floristic richness and regeneration of tree saplings. The ground vegetation was compared in 2 m radius plots around the stem under the canopies of matched conifer-deciduous trees in a mature, conifer-dominated forest, and included in the analysis variables that could potentially mediate the tree effect (soil pH, cover of lichens, bryophytes, leaf and needle litter). The field layer vegetation was more species rich under birch (Betula pendula and B. pubescens) than under conifers (Picea abies and Pinus sylvestris), and several vascular plant species (including saplings of tree species) occurred more often under birch than under conifers. However, when the effect of the number of subordinate trees was taken into account the difference between birch and pine was not significant. The number of tree regenerations (saplings) was lowest under pines, but did not differ between spruce and birch. There were no effects of the canopy species on soil pH or on cover of lichens and bryophytes. The difference in diversity may be caused by the different effects of leaf and needle litter, and it is also likely that canopy structure has an influence via interception and throughfall and by affecting the light and microclimate.
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| 33. |
- Wedén, Christina, et al.
(författare)
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Truffle cultivation in Sweden : Results from Quercus robur and Corylus avellana field trials on the island of Gotland
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24:1, s. 37-53
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Tidskriftsartikel (refereegranskat)abstract
- The edible, ectomycorrhizal Burgundy truffle, Tuber aestivum Vitt., grows naturally on the islands of Gotland and Oland, Sweden. In 1999, 240 inoculated Quercus robur and Corylus avellana seedlings inoculated with French T. aestivum were planted in 10 experimental truffle orchards (truffieres) on Gotland to investigate the possibility of truffle cultivation in Sweden. Truffle orchard management, mycorrhizal development and seedling growth were studied. Fourteen additional truffle orchards containing more than 2000 Q. robur were established during 2000 and 2001. In 2004, T. aestivum mycorrhizae were detected in all truffle orchards. In 2005, the first T. aestivum truffle was found, 6 years after planting. This is the first cultivated truffle in Scandinavia and despite the northerly location they were produced within a timescale comparable with France. Tuber aestivum mycorrhizae survived in soils which differed from naturally producing locations by having a sand content > 95%, pH ≤6.4 and calcium content ≤0.1%. In a second series of experiments Swedish Q. robur, C. avellana and Carpinus betulus seedlings were inoculated with Swedish T. aestivum. Eleven months after inoculation T. aestivum mycorrhizae were found in 0-78% of the seedlings, depending on species, inoculation treatment and substrate. Because of the continuing decline of oaks in Sweden and associated fauna and flora, truffle cultivation may favour oak forest restoration programmes as well as making a direct contribution to rural economies.
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| 34. |
- Weslien, Jan, et al.
(författare)
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Effects of increased forest productivity and warmer climates on carbon sequestration, run-off water quality and accumulation of dead wood in a boreal landscape: A modelling study
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24, s. 333-347
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Tidskriftsartikel (refereegranskat)abstract
- Forest productivity is expected to increase in the future owing to the use of genetically improved plant material and climate warming. Increased productivity will lead to shorter optimum rotation lengths and larger annual clear-cut areas. This study explored the likely effects of increased forest production and a warmer climate in 15 scenarios (five productivity levels and three climate conditions) on: (1) wood production, (2) carbon sequestration, (3) water quality, and (4) amounts of coarse woody debris (CWD). The effects were simulated using a set of ecosystem models incorporating the same climate and management scenarios in a hypothetical managed boreal forest landscape. Under the assumption that increased productivity is coupled to a proportional decrease in rotation length, the outputs at the landscape-level scale were briefly as follows. In each simulated climate scenario, increased productivity resulted in increases in above- and below-ground carbon sequestration, and reduced CWD accumulation, but did not have significant effects on dissolved total nitrogen (DTN) loads in run-off water. In addition, at every simulated productivity level, a warmer climate led to reductions in carbon sequestration below ground and amounts of CWD, but increases in DTN contents in run-off water. Reasons for these trends are identified and explained.
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| 35. |
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| 36. |
- Lidestav, Gun, et al.
(författare)
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Gender and Forestry – A critical discourse analysis of forestry professions in Sweden.
- 2007
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Ingår i: Scandinavian Journal of Forestry. - 0282-7581. ; 22:4, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- In this article, discourse analysis is used to examine how gender, i.e. ideas of specific masculine or feminine qualities, is linked to forestry professions. The dynamic genderization concept is introduced to understand better how and why the process of gender coding takes place within the forestry field. Discourse here is understood as a particular way of using language and other symbolic forms such as visual images, which does not simply reflect or represent social entities and relations, but constructs or constitutes them. The empirical material consists of 55 job advertisements for supervisors and rangers and 142 texts and images about the forestry professions published in the Swedish forestry press during this years 1990-1991 and 2000-2001. The results show that little has changed during the 10 year period. The discourse continues to (re)produce a manifest portrait of the ideal forester as a hard-working and nature-mastering man. This hegemonic masculinity is to a large extent formed around a rural masculine identity with a strong interest in hunting and wildlife. At the same time, several texts reveal that female foresters appeared to need a male mentor to enter the field, especially at the beginning of the 1990s. It is through such a "helper" that they seem to receive legitimacy as professionals. Further, the forestry press tends to make statements that gender does not matter. In conclusion, the increased number of female foresters has not brought with it any significant change in the dominant gender coding of the studied forestry professions.
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