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Regeneration success depends on decisions made based on factors on aregional, site, and microenvironmental level. Therefore, understanding andmapping of such factors between and within sites can guide decisions forbetter seedling establishment. Thus, the aim of this thesis was to findcombinations of regeneration measures that result in low seedling mortalityand high growth. Additionally, to explore the potential of digital tools inregeneration planning. Aims were handled using field experiments and asurvey, by integrating digital tools in the analysis and experimental set-up. Increased precipitation and decreased air temperatures between April andOctober during the planting year lowered seedling mortality. Planting inmineral soil also lowered the mortality rate, which emphasized theimportance of planting and site preparation quality (Paper I). Selection ofsite preparation method was found to be of minor importance. The sitepreparation’s ability to create suitable planting spots was most important forseedling survival and growth. Selection of site preparation affected soildisturbance, and natural regeneration was promoted with all methods usedin the experiments (Paper II). Adapting planting position choice, followingsite preparation, to within-site variation was valuable to decrease mortalityrates and promote growth (Paper II-III). In wet conditions, elevatedplanting positions were advantageous compared to lower ones, but moreflexibility could be applied in drier conditions. Norway spruce, Scots pine,and silver birch reacted differently to planting position choice (Paper III).Paper I-III indicated that digital tools could be used in regenerationplanning. A depth-to-water-raster successfully explained seedling mortalityand growth in the extreme ends of the soil moisture spectrum. Using remotesensing derived variables can be valuable for further mapping andunderstanding of between and within-site variation in future regenerationplanning. There were no long-term negativ, För att lyckas med föryngringsåtgärder krävs beslut baserade på faktorer påregional, bestånds och mikromiljönivå. Därför kan förståelse ochkartläggning av dessa faktorer mellan och inom bestånd vägleda beslut föratt säkerställa god plantetablering. Syftet med denna avhandling var såledesatt hitta kombinationer av föryngringsmetoder som resulterar i lågplantmortalitet och hög tillväxt. Därutöver, utforska potentialen föranvändning av digitala verktyg i föryngringsplanering. Syftena behandladesgenom en användning av fältexperiment och en fältundersökning, genom attintegrera digitala verktyg i analyser och försöksutlägg. En ökning i nederbörd och lägre lufttemperatur mellan april och oktoberunder planteringsåret sänkte plantmortaliteten. Plantering i mineraljordledde också till lägre mortalitet, vilket visar på betydelsen av planteringensoch markberedningens kvalitet. Valet av markberedningsmetod hademindre betydelse. Det viktigaste för överlevnad och tillväxt varmarkberedningens förmåga att skapa bra planteringspunkter.Markstörningen påverkades av valet av markberedningsmetod och naturligföryngring gynnades av alla använda metoder i försöken. Att anpassa valetav planteringsposition, efter utförd markberedning, tillståndortsförhållanden var värdefullt för att minska mortaliteten och gynnatillväxten. Upphöjda positioner var fördelaktiga när förhållandena var blötamen valet kunde vara mer fritt när det blev torrare. Gran, tall, och björkreagerade olika på valet av planteringsposition. Artikel I-III indikerade attdigitala verktyg skulle kunna användas i föryngringsplanering. Ett depth-towater-raster förklarade plantmortaliteten och tillväxten i de extrema delarnaav markfuktighetsskalan. Användningen av fjärranalysvariabler kan blivärdefullt för fortsatt kartläggning och förståelse av ståndortsvariationmellan och inom bestånd i framtida föryngringsplanering. Markberedningledde inte till några negativa effekter på produktionsförmågan. Volymen varstörst efter hyggesplöjning

The introduction of exotic tree species can have profound effects on the native environment, including habitat use and movement patterns of animals, as well as becoming a management challenge for other land users. Here, we used GPS data from reindeer (Rangifer tarandus) and remote sensing measurements of lichen cover and soil moisture to assess the effects of the exotic lodgepole pine (Pinus contorta) on reindeer husbandry by the Indigenous Sámi in northern Sweden. We used locational data from 67 reindeer for three winters to analyze their habitat selection at the second-order selection (placement of home range in the landscape) and third-order selection (selection of sites within the home range) in relation to land cover class, terricolous lichen cover as measure of winter forage abundance, topographic features, and distance to roads. We also analyzed remotely sensed abundance of lichens in different forest types, and the association between these forest types and soil moisture as measure of suitability as lichen habitat. Compared to native P. sylvestris, we found that reindeer avoided stands with P. contorta where trees were higher than three meters. If P. contorta was the dominant tree species, reindeer were 60 % less likely to select these stands compared to stands with P. sylvestris, and 40 % less likely if P. contorta was less dominant at both orders of selection. We also found that reindeer selected areas with higher lichen cover. Lichen cover was lower in P. contorta stands compared to stands of the native P. sylvestris, even though P. contorta occurred mainly on dry soils usually favorable for terricolous lichens. We conclude that planting P. contorta on soils suitable for terricolous lichens is likely to reduce forage availability for reindeer and turn habitats earlier preferred by reindeer into avoided habitat, resulting in an overall reduction of winter grazing grounds. The effects of stands with P. contorta, albeit covering a comparatively small percent

The introduction of exotic tree species can have profound effects on the native environment, including habitat use and movement patterns of animals, as well as becoming a management challenge for other land users. Here, we used GPS data from reindeer (Rangifer tarandus) and remote sensing measurements of lichen cover and soil moisture to assess the effects of the exotic lodgepole pine (Pinus contorta) on reindeer husbandry by the Indigenous Sámi in northern Sweden. We used locational data from 67 reindeer for three winters to analyze their habitat selection at the second-order selection (placement of home range in the landscape) and third-order selection (selection of sites within the home range) in relation to land cover class, terricolous lichen cover as measure of winter forage abundance, topographic features, and distance to roads. We also analyzed remotely sensed abundance of lichens in different forest types, and the association between these forest types and soil moisture as measure of suitability as lichen habitat. Compared to native P. sylvestris, we found that reindeer avoided stands with P. contorta where trees were higher than three meters. If P. contorta was the dominant tree species, reindeer were 60 % less likely to select these stands compared to stands with P. sylvestris, and 40 % less likely if P. contorta was less dominant at both orders of selection. We also found that reindeer selected areas with higher lichen cover. Lichen cover was lower in P. contorta stands compared to stands of the native P. sylvestris, even though P. contorta occurred mainly on dry soils usually favorable for terricolous lichens. We conclude that planting P. contorta on soils suitable for terricolous lichens is likely to reduce forage availability for reindeer and turn habitats earlier preferred by reindeer into avoided habitat, resulting in an overall reduction of winter grazing grounds. The effects of stands with P. contorta, albeit covering a comparatively small percent

The introduction of exotic tree species can have profound effects on the native environment, including habitat use and movement patterns of animals, as well as becoming a management challenge for other land users. Here, we used GPS data from reindeer (Rangifer tarandus) and remote sensing measurements of lichen cover and soil moisture to assess the effects of the exotic lodgepole pine (Pinus contorta) on reindeer husbandry by the Indigenous Sámi in northern Sweden. We used locational data from 67 reindeer for three winters to analyze their habitat selection at the second-order selection (placement of home range in the landscape) and third-order selection (selection of sites within the home range) in relation to land cover class, terricolous lichen cover as measure of winter forage abundance, topographic features, and distance to roads. We also analyzed remotely sensed abundance of lichens in different forest types, and the association between these forest types and soil moisture as measure of suitability as lichen habitat. Compared to native P. sylvestris, we found that reindeer avoided stands with P. contorta where trees were higher than three meters. If P. contorta was the dominant tree species, reindeer were 60 % less likely to select these stands compared to stands with P. sylvestris, and 40 % less likely if P. contorta was less dominant at both orders of selection. We also found that reindeer selected areas with higher lichen cover. Lichen cover was lower in P. contorta stands compared to stands of the native P. sylvestris, even though P. contorta occurred mainly on dry soils usually favorable for terricolous lichens. We conclude that planting P. contorta on soils suitable for terricolous lichens is likely to reduce forage availability for reindeer and turn habitats earlier preferred by reindeer into avoided habitat, resulting in an overall reduction of winter grazing grounds. The effects of stands with P. contorta, albeit covering a comparatively small percent

Tack vare vissa önskade egenskaper gjordes en storsatsning på contortatall (Pinus contorta) i Sverige på 70-talet. Idag finns cirka 600 000 ha i Sverige som det gjorts provsågningar på och är nu dags att hitta användningsområden till. Syftet med denna studie var att undersöka skillnaden i utbyte mellan contortatall och gran (Picea abies) efter hyvling. Målet var att undersöka om sidobrädor av contortatall kan vara ett substitut till sidobrädor av gran vid hyvling ämnat för den amerikanska marknaden.Efter skanning av brädor samt manuell visuell sortering visade det sig att 92 % av granbrädorna var utan defekt medan 24 % av contortatallen var det. 34 % av contortatallen nedklassades för hål och 3 % av granen. Slutsatsen av studien visar att mängden och storleken på kvistarna är ett problem för contortatallvirket. För att få ett högkvalitativt virke behövs en djupare översyn av tillvägagångssättet för torkning och trädens tillväxtförhållanden.

Regeneration success depends on decisions made based on factors on aregional, site, and microenvironmental level. Therefore, understanding andmapping of such factors between and within sites can guide decisions forbetter seedling establishment. Thus, the aim of this thesis was to findcombinations of regeneration measures that result in low seedling mortalityand high growth. Additionally, to explore the potential of digital tools inregeneration planning. Aims were handled using field experiments and asurvey, by integrating digital tools in the analysis and experimental set-up. Increased precipitation and decreased air temperatures between April andOctober during the planting year lowered seedling mortality. Planting inmineral soil also lowered the mortality rate, which emphasized theimportance of planting and site preparation quality (Paper I). Selection ofsite preparation method was found to be of minor importance. The sitepreparation’s ability to create suitable planting spots was most important forseedling survival and growth. Selection of site preparation affected soildisturbance, and natural regeneration was promoted with all methods usedin the experiments (Paper II). Adapting planting position choice, followingsite preparation, to within-site variation was valuable to decrease mortalityrates and promote growth (Paper II-III). In wet conditions, elevatedplanting positions were advantageous compared to lower ones, but moreflexibility could be applied in drier conditions. Norway spruce, Scots pine,and silver birch reacted differently to planting position choice (Paper III).Paper I-III indicated that digital tools could be used in regenerationplanning. A depth-to-water-raster successfully explained seedling mortalityand growth in the extreme ends of the soil moisture spectrum. Using remotesensing derived variables can be valuable for further mapping andunderstanding of between and within-site variation in future regenerationplanning. There were no long-term negativ, För att lyckas med föryngringsåtgärder krävs beslut baserade på faktorer påregional, bestånds och mikromiljönivå. Därför kan förståelse ochkartläggning av dessa faktorer mellan och inom bestånd vägleda beslut föratt säkerställa god plantetablering. Syftet med denna avhandling var såledesatt hitta kombinationer av föryngringsmetoder som resulterar i lågplantmortalitet och hög tillväxt. Därutöver, utforska potentialen föranvändning av digitala verktyg i föryngringsplanering. Syftena behandladesgenom en användning av fältexperiment och en fältundersökning, genom attintegrera digitala verktyg i analyser och försöksutlägg. En ökning i nederbörd och lägre lufttemperatur mellan april och oktoberunder planteringsåret sänkte plantmortaliteten. Plantering i mineraljordledde också till lägre mortalitet, vilket visar på betydelsen av planteringensoch markberedningens kvalitet. Valet av markberedningsmetod hademindre betydelse. Det viktigaste för överlevnad och tillväxt varmarkberedningens förmåga att skapa bra planteringspunkter.Markstörningen påverkades av valet av markberedningsmetod och naturligföryngring gynnades av alla använda metoder i försöken. Att anpassa valetav planteringsposition, efter utförd markberedning, tillståndortsförhållanden var värdefullt för att minska mortaliteten och gynnatillväxten. Upphöjda positioner var fördelaktiga när förhållandena var blötamen valet kunde vara mer fritt när det blev torrare. Gran, tall, och björkreagerade olika på valet av planteringsposition. Artikel I-III indikerade attdigitala verktyg skulle kunna användas i föryngringsplanering. Ett depth-towater-raster förklarade plantmortaliteten och tillväxten i de extrema delarnaav markfuktighetsskalan. Användningen av fjärranalysvariabler kan blivärdefullt för fortsatt kartläggning och förståelse av ståndortsvariationmellan och inom bestånd i framtida föryngringsplanering. Markberedningledde inte till några negativa effekter på produktionsförmågan. Volymen varstörst efter hyggesplöjning

Regeneration success depends on decisions made based on factors on aregional, site, and microenvironmental level. Therefore, understanding andmapping of such factors between and within sites can guide decisions forbetter seedling establishment. Thus, the aim of this thesis was to findcombinations of regeneration measures that result in low seedling mortalityand high growth. Additionally, to explore the potential of digital tools inregeneration planning. Aims were handled using field experiments and asurvey, by integrating digital tools in the analysis and experimental set-up. Increased precipitation and decreased air temperatures between April andOctober during the planting year lowered seedling mortality. Planting inmineral soil also lowered the mortality rate, which emphasized theimportance of planting and site preparation quality (Paper I). Selection ofsite preparation method was found to be of minor importance. The sitepreparation’s ability to create suitable planting spots was most important forseedling survival and growth. Selection of site preparation affected soildisturbance, and natural regeneration was promoted with all methods usedin the experiments (Paper II). Adapting planting position choice, followingsite preparation, to within-site variation was valuable to decrease mortalityrates and promote growth (Paper II-III). In wet conditions, elevatedplanting positions were advantageous compared to lower ones, but moreflexibility could be applied in drier conditions. Norway spruce, Scots pine,and silver birch reacted differently to planting position choice (Paper III).Paper I-III indicated that digital tools could be used in regenerationplanning. A depth-to-water-raster successfully explained seedling mortalityand growth in the extreme ends of the soil moisture spectrum. Using remotesensing derived variables can be valuable for further mapping andunderstanding of between and within-site variation in future regenerationplanning. There were no long-term negativ, För att lyckas med föryngringsåtgärder krävs beslut baserade på faktorer påregional, bestånds och mikromiljönivå. Därför kan förståelse ochkartläggning av dessa faktorer mellan och inom bestånd vägleda beslut föratt säkerställa god plantetablering. Syftet med denna avhandling var såledesatt hitta kombinationer av föryngringsmetoder som resulterar i lågplantmortalitet och hög tillväxt. Därutöver, utforska potentialen föranvändning av digitala verktyg i föryngringsplanering. Syftena behandladesgenom en användning av fältexperiment och en fältundersökning, genom attintegrera digitala verktyg i analyser och försöksutlägg. En ökning i nederbörd och lägre lufttemperatur mellan april och oktoberunder planteringsåret sänkte plantmortaliteten. Plantering i mineraljordledde också till lägre mortalitet, vilket visar på betydelsen av planteringensoch markberedningens kvalitet. Valet av markberedningsmetod hademindre betydelse. Det viktigaste för överlevnad och tillväxt varmarkberedningens förmåga att skapa bra planteringspunkter.Markstörningen påverkades av valet av markberedningsmetod och naturligföryngring gynnades av alla använda metoder i försöken. Att anpassa valetav planteringsposition, efter utförd markberedning, tillståndortsförhållanden var värdefullt för att minska mortaliteten och gynnatillväxten. Upphöjda positioner var fördelaktiga när förhållandena var blötamen valet kunde vara mer fritt när det blev torrare. Gran, tall, och björkreagerade olika på valet av planteringsposition. Artikel I-III indikerade attdigitala verktyg skulle kunna användas i föryngringsplanering. Ett depth-towater-raster förklarade plantmortaliteten och tillväxten i de extrema delarnaav markfuktighetsskalan. Användningen av fjärranalysvariabler kan blivärdefullt för fortsatt kartläggning och förståelse av ståndortsvariationmellan och inom bestånd i framtida föryngringsplanering. Markberedningledde inte till några negativa effekter på produktionsförmågan. Volymen varstörst efter hyggesplöjning

Regeneration success depends on decisions made based on factors on aregional, site, and microenvironmental level. Therefore, understanding andmapping of such factors between and within sites can guide decisions forbetter seedling establishment. Thus, the aim of this thesis was to findcombinations of regeneration measures that result in low seedling mortalityand high growth. Additionally, to explore the potential of digital tools inregeneration planning. Aims were handled using field experiments and asurvey, by integrating digital tools in the analysis and experimental set-up. Increased precipitation and decreased air temperatures between April andOctober during the planting year lowered seedling mortality. Planting inmineral soil also lowered the mortality rate, which emphasized theimportance of planting and site preparation quality (Paper I). Selection ofsite preparation method was found to be of minor importance. The sitepreparation’s ability to create suitable planting spots was most important forseedling survival and growth. Selection of site preparation affected soildisturbance, and natural regeneration was promoted with all methods usedin the experiments (Paper II). Adapting planting position choice, followingsite preparation, to within-site variation was valuable to decrease mortalityrates and promote growth (Paper II-III). In wet conditions, elevatedplanting positions were advantageous compared to lower ones, but moreflexibility could be applied in drier conditions. Norway spruce, Scots pine,and silver birch reacted differently to planting position choice (Paper III).Paper I-III indicated that digital tools could be used in regenerationplanning. A depth-to-water-raster successfully explained seedling mortalityand growth in the extreme ends of the soil moisture spectrum. Using remotesensing derived variables can be valuable for further mapping andunderstanding of between and within-site variation in future regenerationplanning. There were no long-term negativ, För att lyckas med föryngringsåtgärder krävs beslut baserade på faktorer påregional, bestånds och mikromiljönivå. Därför kan förståelse ochkartläggning av dessa faktorer mellan och inom bestånd vägleda beslut föratt säkerställa god plantetablering. Syftet med denna avhandling var såledesatt hitta kombinationer av föryngringsmetoder som resulterar i lågplantmortalitet och hög tillväxt. Därutöver, utforska potentialen föranvändning av digitala verktyg i föryngringsplanering. Syftena behandladesgenom en användning av fältexperiment och en fältundersökning, genom attintegrera digitala verktyg i analyser och försöksutlägg. En ökning i nederbörd och lägre lufttemperatur mellan april och oktoberunder planteringsåret sänkte plantmortaliteten. Plantering i mineraljordledde också till lägre mortalitet, vilket visar på betydelsen av planteringensoch markberedningens kvalitet. Valet av markberedningsmetod hademindre betydelse. Det viktigaste för överlevnad och tillväxt varmarkberedningens förmåga att skapa bra planteringspunkter.Markstörningen påverkades av valet av markberedningsmetod och naturligföryngring gynnades av alla använda metoder i försöken. Att anpassa valetav planteringsposition, efter utförd markberedning, tillståndortsförhållanden var värdefullt för att minska mortaliteten och gynnatillväxten. Upphöjda positioner var fördelaktiga när förhållandena var blötamen valet kunde vara mer fritt när det blev torrare. Gran, tall, och björkreagerade olika på valet av planteringsposition. Artikel I-III indikerade attdigitala verktyg skulle kunna användas i föryngringsplanering. Ett depth-towater-raster förklarade plantmortaliteten och tillväxten i de extrema delarnaav markfuktighetsskalan. Användningen av fjärranalysvariabler kan blivärdefullt för fortsatt kartläggning och förståelse av ståndortsvariationmellan och inom bestånd i framtida föryngringsplanering. Markberedningledde inte till några negativa effekter på produktionsförmågan. Volymen varstörst efter hyggesplöjning

The introduction of exotic tree species can have profound effects on the native environment, including habitat use and movement patterns of animals, as well as becoming a management challenge for other land users. Here, we used GPS data from reindeer (Rangifer tarandus) and remote sensing measurements of lichen cover and soil moisture to assess the effects of the exotic lodgepole pine (Pinus contorta) on reindeer husbandry by the Indigenous Sámi in northern Sweden. We used locational data from 67 reindeer for three winters to analyze their habitat selection at the second-order selection (placement of home range in the landscape) and third-order selection (selection of sites within the home range) in relation to land cover class, terricolous lichen cover as measure of winter forage abundance, topographic features, and distance to roads. We also analyzed remotely sensed abundance of lichens in different forest types, and the association between these forest types and soil moisture as measure of suitability as lichen habitat. Compared to native P. sylvestris, we found that reindeer avoided stands with P. contorta where trees were higher than three meters. If P. contorta was the dominant tree species, reindeer were 60 % less likely to select these stands compared to stands with P. sylvestris, and 40 % less likely if P. contorta was less dominant at both orders of selection. We also found that reindeer selected areas with higher lichen cover. Lichen cover was lower in P. contorta stands compared to stands of the native P. sylvestris, even though P. contorta occurred mainly on dry soils usually favorable for terricolous lichens. We conclude that planting P. contorta on soils suitable for terricolous lichens is likely to reduce forage availability for reindeer and turn habitats earlier preferred by reindeer into avoided habitat, resulting in an overall reduction of winter grazing grounds. The effects of stands with P. contorta, albeit covering a comparatively small percent

Tack vare vissa önskade egenskaper gjordes en storsatsning på contortatall (Pinus contorta) i Sverige på 70-talet. Idag finns cirka 600 000 ha i Sverige som det gjorts provsågningar på och är nu dags att hitta användningsområden till. Syftet med denna studie var att undersöka skillnaden i utbyte mellan contortatall och gran (Picea abies) efter hyvling. Målet var att undersöka om sidobrädor av contortatall kan vara ett substitut till sidobrädor av gran vid hyvling ämnat för den amerikanska marknaden.Efter skanning av brädor samt manuell visuell sortering visade det sig att 92 % av granbrädorna var utan defekt medan 24 % av contortatallen var det. 34 % av contortatallen nedklassades för hål och 3 % av granen. Slutsatsen av studien visar att mängden och storleken på kvistarna är ett problem för contortatallvirket. För att få ett högkvalitativt virke behövs en djupare översyn av tillvägagångssättet för torkning och trädens tillväxtförhållanden.

The introduction of exotic tree species can have profound effects on the native environment, including habitat use and movement patterns of animals, as well as becoming a management challenge for other land users. Here, we used GPS data from reindeer (Rangifer tarandus) and remote sensing measurements of lichen cover and soil moisture to assess the effects of the exotic lodgepole pine (Pinus contorta) on reindeer husbandry by the Indigenous Sámi in northern Sweden. We used locational data from 67 reindeer for three winters to analyze their habitat selection at the second-order selection (placement of home range in the landscape) and third-order selection (selection of sites within the home range) in relation to land cover class, terricolous lichen cover as measure of winter forage abundance, topographic features, and distance to roads. We also analyzed remotely sensed abundance of lichens in different forest types, and the association between these forest types and soil moisture as measure of suitability as lichen habitat. Compared to native P. sylvestris, we found that reindeer avoided stands with P. contorta where trees were higher than three meters. If P. contorta was the dominant tree species, reindeer were 60 % less likely to select these stands compared to stands with P. sylvestris, and 40 % less likely if P. contorta was less dominant at both orders of selection. We also found that reindeer selected areas with higher lichen cover. Lichen cover was lower in P. contorta stands compared to stands of the native P. sylvestris, even though P. contorta occurred mainly on dry soils usually favorable for terricolous lichens. We conclude that planting P. contorta on soils suitable for terricolous lichens is likely to reduce forage availability for reindeer and turn habitats earlier preferred by reindeer into avoided habitat, resulting in an overall reduction of winter grazing grounds. The effects of stands with P. contorta, albeit covering a comparatively small percent

As a result of the global world we today live in, species are transported outside of their native range to new areas. Some of these species becomes invasive, which can cause a variety of negative effects. Traits are often thought to play an important role in invasion success. The purpose with this thesis was therefore to test if and how traits of the invasion species Pinus contorta varied depending on the subspecies, and where it is growing (i.e. native or introduced range). Samples had prior to this thesis been gathered from 3 subspecies of P. contorta in its native range (USA) and from an unspecified subspecies in plantations and invasion fronts in an introduced range (Patagonia). Traits of sampled needles, seeds and cones were then used as a basis for multivariate and univariate analyses to detect significant differences between the sampled categories. Significant trait differences were found between the three native subspecies: latifolia, murrayana and contorta. The Patagonian P. contorta was found to be the most similar to the native subspecies murrayana. Also, the Patagonian P. contorta had traits that differed significantly from all of the native subspecies. Overall I found no statistical evidence of a lower trait variation in the introduced P. contorta compared to the native. I further found some trait differences between the Patagonian P. contorta trees in the plantations and at the invasion front. As a whole my results indicate that invasive species can differ in traits when comparing the species in the native and introduced range, thus providing an example of an invasive species displaying a change in traits compared to their native range. The results can also be used to support several of the existing hypotheses regarding invasion success.

Endophytes have been defined as microorganisms living inside plant tissues without causing negative effects on their hosts. Endophytic microbes have been extensively studied for their plant growth-promoting traits. However, analyses of endophytes require complete removal of epiphytic microorganisms. We found that the established tests to evaluate surface sterility, polymerase chain reaction, and leaf imprints, are unreliable. Therefore, we used scanning electron microscopy (SEM) as an additional assessment of epiphyte removal. We used a diverse suite of sterilization protocols to remove epiphytic microorganisms from the leaves of a gymnosperm and an angiosperm tree to test the influence of leaf morphology on the efficacy of these methods. Additionally, leaf tissue damage was also evaluated by SEM, as damaging the leaves might have an impact on endophytes and could lead to inaccurate assessment of endophytic communities. Our study indicates, that complete removal of the leaf cuticle by the sterilization technique assures loss of epiphytic microbes, and that leaves of different tree species may require different sterilization protocols. Furthermore, our study demonstrates the importance of choosing the appropriate sterilization protocol to prevent erroneous interpretation of host-endophyte interactions. Moreover, it shows the utility of SEM for evaluating the effectiveness of surface sterilization methods and their impact on leaf tissue integrity.

Pinus Contorta was introduced to Sweden as a tree that would grow fast with a promising future, also a promise in increased production. What could not be anticipated was the common Swedish weather conditions, such as snow and wind, would have negative impact on Pinus contorta due to its instability connected to fast-growing trunk and wide crown. Those predictions were hard to estimate since these weather conditions also is common in Canada, where it has its origins. The overall damage caused by snow and wind generates an annual loss of approximately hundred million Swedish crowns (SEK), which has a great impact on the Swedish forestry economy. The awareness of the risks and damages on Pinus contorta makes it possible to both prevent and avoid these to some extent. A more detailed study has been done in the Swedish region Norrbotten, where the level of the damage on Pinus contorta was compared to the Swedish pine. The study included inventory of un-thinned stands and quantified data was collected. The conclusions indicated that the level of damage on Pinus contorta stands was more than twice the damage of the Pinus sylvestris stands. However, since Pinus contorta is relatively new in Sweden, the results regarding the future of the contorta pine are therefore insufficient. Furthermore, it is not possible to predict if the promised increase of production will ever be achieved. To achieved reliable results, further studies are suggested where both loss of profit, compared to the Pinus sylvestris stands, but also the full turnaround time of Pinus contorta are included.

Endophytes have been defined as microorganisms living inside plant tissues without causing negative effects on their hosts. Endophytic microbes have been extensively studied for their plant growth-promoting traits. However, analyses of endophytes require complete removal of epiphytic microorganisms. We found that the established tests to evaluate surface sterility, polymerase chain reaction, and leaf imprints, are unreliable. Therefore, we used scanning electron microscopy (SEM) as an additional assessment of epiphyte removal. We used a diverse suite of sterilization protocols to remove epiphytic microorganisms from the leaves of a gymnosperm and an angiosperm tree to test the influence of leaf morphology on the efficacy of these methods. Additionally, leaf tissue damage was also evaluated by SEM, as damaging the leaves might have an impact on endophytes and could lead to inaccurate assessment of endophytic communities. Our study indicates, that complete removal of the leaf cuticle by the sterilization technique assures loss of epiphytic microbes, and that leaves of different tree species may require different sterilization protocols. Furthermore, our study demonstrates the importance of choosing the appropriate sterilization protocol to prevent erroneous interpretation of host-endophyte interactions. Moreover, it shows the utility of SEM for evaluating the effectiveness of surface sterilization methods and their impact on leaf tissue integrity.

Pinus Contorta was introduced to Sweden as a tree that would grow fast with a promising future, also a promise in increased production. What could not be anticipated was the common Swedish weather conditions, such as snow and wind, would have negative impact on Pinus contorta due to its instability connected to fast-growing trunk and wide crown. Those predictions were hard to estimate since these weather conditions also is common in Canada, where it has its origins. The overall damage caused by snow and wind generates an annual loss of approximately hundred million Swedish crowns (SEK), which has a great impact on the Swedish forestry economy. The awareness of the risks and damages on Pinus contorta makes it possible to both prevent and avoid these to some extent. A more detailed study has been done in the Swedish region Norrbotten, where the level of the damage on Pinus contorta was compared to the Swedish pine. The study included inventory of un-thinned stands and quantified data was collected. The conclusions indicated that the level of damage on Pinus contorta stands was more than twice the damage of the Pinus sylvestris stands. However, since Pinus contorta is relatively new in Sweden, the results regarding the future of the contorta pine are therefore insufficient. Furthermore, it is not possible to predict if the promised increase of production will ever be achieved. To achieved reliable results, further studies are suggested where both loss of profit, compared to the Pinus sylvestris stands, but also the full turnaround time of Pinus contorta are included.

[EN] Large-scale forest disturbances including mountain pine beetle infestation and forest fires have generated overstocked lodgepole pine stands in the interior of British Columbia. A critical need is to determine sustainable management strategies to ensure their healthy growth and provision of various ecological functions under increased drought risk due to climate change. In 2016, a field experiment was established to study the effects of juvenile thinning on carbon assimilation and water use at the both tree- and stand-scales in a 16-year old lodgepole pine stand from June to October in 2016 and 2017. This study located northeast of Penticton, British Columbia, included two thinning treatments (T1: 4500 stems per ha; and T2: 1100 stems per ha) and one control (C: 27,000 stems per ha), randomly assigned in three blocks. Sap flow and microclimatic variables were continuously monitered in one plot of each treatment in one block, while tree diameter at breast height were measured across the three blocks. The results showed that C had the lowest tree radial growth (0.14 mm(2)/d), sap flow velocity (64.61 g/cm(2)d), and highest stand transpiration (4.36 mm/d), while T2 had the highest tree radial growth (1.28 mm(2)/d), sap flow velocity (149.14 g/cm(2)d), and lowest stand transpiration (0.36 mm/d) over the two-year study period. Significant differences of tree radial growth and sap flow velocity between T1 and T2 only occurred under the drought condition (in the summer season of 2017), with T2 having a significant higher resistant index of sap flow velocity than C and T1, by taking advantage of the change in microclimatic conditions following intense thinning. At the stand-level, only the stand transpiration of T1 statistically decreased in the drought year. We conclude that the thinning plays a significant and positive role in maintaining tree growth and water consumption in the short term, and the more heavily thinning (T2) would be more effective to mitigate the dr

Mixing tree species could be a silviculture model that allows early harvest of short-rotation trees, while longer-rotation crop trees remain in the stand. We examined the effects on growth and tree characteristics in a planted experiment with lodgepole pine (LP) and elite-bred Scots pine (SP) in mixed (50/50) and monospecific plots in three different spacings (at 28 years of age after planting). The future development under different thinning regimes, including net present value for one rotation, was analyzed using the Heureka simulation software. As expected, LP had higher survival and initially more rapid growth than SP, with highest stand productivity and biomass production in LP monoculture during a rotation period as a result. However, intimate mixtures of SP and LP at the two widest spacings could give greater production and economic benefits, compared to SP in monoculture. It seems that elite-bred SP will differ in competitiveness against LP, depending on spacing for growth and some quality traits (branch and bark thickness, height of green crown). The findings support developing management systems for combining sparsely planted, and expensive, elite-bred SP in mixture with other trees that maintains high stem volume production and secures certain properties of trees and stands.

Pinus contorta fördes in i Sverige för ett mer storskaligt brukande under 1970-talet för att fylla den förutspådda virkessvackan. Contortan importerades från Nordamerika och är idag Sveriges tredje största barrträd, då den är planterad på ca 600 000 ha. Studier av contortan hade visat att dess kottar var serotina, vilket betyder att de är kådslutna och kräver hög värme för att öppna sig. Det som dock inte tagits i så stor beaktan vid införandet i Sverige var att contortan även producerar icke-serotina kottar och att själva kottproduktionen startar redan vid 5 - 10 års ålder. Det som senare visat sig i flertalet länder, till exempel på Nya Zeeland, var att contortan har en stor förmåga att självsprida sig på störda marker och att den höga värmen som krävs för att kottarna ska öppna sig uppnås om kottarna befinner sig på eller så nära som 30 cm från marken. Kunskapsluckan kring självspridning av contortan i Sverige är ganska stor eftersom få studier i ämnet har utförts, vilket ledde till att vi i denna litteraturstudie ville försöka sammanfatta det som finns studerat sedan tidigare och försöka skapa en bild av contortans invasiva beteende. I de studier som gjorts har det visat sig att contortan kan sprida sig på i stort sett alla marker, även på impedimentmarker, vilket kommer bli ett problem i framtiden om vi ska kunna bevara våra skyddsvärda biotoper utan exotiska trädslags inblandning., Pinus contorta was introduced in Sweden in a bigger perspective than before around the 1970s, and the reason was to fill the approaching timber shortage. The lodgepole pine (LP) was imported from North America and today it is the third biggest conifer in Sweden, and it is planted on around 600 000 ha. Studies of the lodgepole pine has shown that LP has serotinous cones, which means that they are closed with resin and needes to be heated up to open and to loose the seeds. It was not considered when the species was introduced, that it also produces non-serotinous cones and that the cone production starts when the trees are 5-10 years. Studies from several countries (fore example New Zealand) has shown that LP has a high capability to self regenerate on disturbed land and that the high heat that is needed for the cones to open up, is fulfilled if the cones lays on the ground or is about 30 cm from the ground. The gap in knowledge about self regeneration of LP in Sweden is quite big and few studies has been made, which encourage us to try summarize accomplished studies and try to make an image of the invasiveness of LP. Results from other studies has shown that the spread of LP can occur on broadly every types of soils, even on unproductive land. This will be a problem in the future if we want to protect our natural habitats, without exotical implication.

Understanding how climate warming will affect the demographic rates of different ecotypes is critical to predicting shifts in species distributions. Here, we present results from a common garden, climate change experiment in which we measured seedling recruitment of lodgepole pine, a widespread North American conifer that is also planted globally. Seeds from a low-elevation provenance had more than three-fold greater recruitment to their third year than seeds from a high-elevation provenance across sites within and above its native elevation range and across climate manipulations. Heating halved recruitment to the third year of both low- and high-elevation seed sources across the elevation gradient, while watering more than doubled recruitment, alleviating some of the negative effects of heating. Demographic models based on recruitment data from the climate manipulations and long-term observations of adult populations revealed that heating could effectively halt modeled upslope range expansion except when combined with watering. Simulating fire and rapid postfire forest recovery at lower elevations accelerated lodgepole pine expansion into the alpine, but did not alter final abundance rankings among climate scenarios. Regardless of climate scenario, greater recruitment of low-elevation seeds compensated for longer dispersal distances to treeline, assuming colonization was allowed to proceed over multiple centuries. Our results show that ecotypes from lower elevations within a species' range could enhance recruitment and facilitate upslope range shifts with climate change.

Understanding how climate warming will affect the demographic rates of different ecotypes is critical to predicting shifts in species distributions. Here, we present results from a common garden, climate change experiment in which we measured seedling recruitment of lodgepole pine, a widespread North American conifer that is also planted globally. Seeds from a low-elevation provenance had more than three-fold greater recruitment to their third year than seeds from a high-elevation provenance across sites within and above its native elevation range and across climate manipulations. Heating halved recruitment to the third year of both low- and high-elevation seed sources across the elevation gradient, while watering more than doubled recruitment, alleviating some of the negative effects of heating. Demographic models based on recruitment data from the climate manipulations and long-term observations of adult populations revealed that heating could effectively halt modeled upslope range expansion except when combined with watering. Simulating fire and rapid postfire forest recovery at lower elevations accelerated lodgepole pine expansion into the alpine, but did not alter final abundance rankings among climate scenarios. Regardless of climate scenario, greater recruitment of low-elevation seeds compensated for longer dispersal distances to treeline, assuming colonization was allowed to proceed over multiple centuries. Our results show that ecotypes from lower elevations within a species' range could enhance recruitment and facilitate upslope range shifts with climate change.

In this version 13 new plots of White elder and 13 new plots of Sitka spruce were added, both from the collection of the former Stichting Industriehout. This database is part of the FEM growth and yield database, a collection of growth and yield data from even-aged monocultures.

Mountain meadows have high biodiversity and help regulate stream water release following the snowmelt pulse. However, many meadows are experiencing woody plant encroachment, threatening these ecosystem services. While there have been field surveys of individual meadows and remote sensing-based landscape-scale studies of encroachment, what is missing is a broad-scale, ground-based study to understand common regional drivers, especially at high elevations, where land management has often played a less direct role. With this study, we ask: What are the climate and landscape conditions conducive to woody plant encroachment at the landscape scale, and how has historical climate variation affected tree recruitment in subalpine meadows over time? We measured density of encroaching trees across 340 subalpine meadows in the central Sierra Nevada, California, USA, and used generalized additive models (GAMs) to determine the relationship between landscape-scale patterns of encroachment and meadow environmental properties. We determined ages of trees in 30 survey meadows, used observed climate and GAMs to model the relationship between timing of recruitment and climate since the early 1900s, and extrapolated recruitment patterns into the future using downscaled climate scenarios. Encroachment was high among meadows with lodgepole pine (Pinus contorta Douglas ex Loudon var. murrayana (Balf.) Engelm.) in the immediate vicinity, at lower elevations, with physical conditions favoring strong soil drying, and with maximum temperatures above or below average. Climatic conditions during the year of germination were unimportant, with tree recruitment instead depending on a 3-yr seed production period prior to germination and a 6-yr seedling establishment period following germination. Recruitment was high when the seed production period had high snowpack, and when the seedling establishment period had warm summer maximum temperatures, high summer precipitation, and high snowpack. Applyin

Mountain meadows have high biodiversity and help regulate stream water release following the snowmelt pulse. However, many meadows are experiencing woody plant encroachment, threatening these ecosystem services. While there have been field surveys of individual meadows and remote sensing-based landscape-scale studies of encroachment, what is missing is a broad-scale, ground-based study to understand common regional drivers, especially at high elevations, where land management has often played a less direct role. With this study, we ask: What are the climate and landscape conditions conducive to woody plant encroachment at the landscape scale, and how has historical climate variation affected tree recruitment in subalpine meadows over time? We measured density of encroaching trees across 340 subalpine meadows in the central Sierra Nevada, California, USA, and used generalized additive models (GAMs) to determine the relationship between landscape-scale patterns of encroachment and meadow environmental properties. We determined ages of trees in 30 survey meadows, used observed climate and GAMs to model the relationship between timing of recruitment and climate since the early 1900s, and extrapolated recruitment patterns into the future using downscaled climate scenarios. Encroachment was high among meadows with lodgepole pine (Pinus contorta Douglas ex Loudon var. murrayana (Balf.) Engelm.) in the immediate vicinity, at lower elevations, with physical conditions favoring strong soil drying, and with maximum temperatures above or below average. Climatic conditions during the year of germination were unimportant, with tree recruitment instead depending on a 3-yr seed production period prior to germination and a 6-yr seedling establishment period following germination. Recruitment was high when the seed production period had high snowpack, and when the seedling establishment period had warm summer maximum temperatures, high summer precipitation, and high snowpack. Applyin

We have synthesized available data for calcium (Ca) dynamics in decomposing foliar litter of mainly pine (Pinus), spruce (Picea), and birch (Betula) species to determine patterns of Ca concentration with climate in newly shed litter and its dynamics in decomposing litter as well as a possible role for Ca as regards limit values. Initial Ca concentration was negatively related to mean annual precipitation (MAP) with different relationships among genera. A limited data set showed a positive relationship across species (p < 0.05) to extractable Ca in soil. In paired stands, litter of both Norway spruce (Picea abies) and lodgepole pine (Pinus contorta) had higher Ca concentrations than Scots pine (Pinus silvestris), Norway spruce litter even twice as high. Relationships between initial concentrations of Ca and those of other nutrients appeared to be dominated by the positive ones to potassium (K) and magnesium (Mg) and specifically for deciduous litter there was a negative relationship to nitrogen (N). In decomposing litter, Ca concentration followed a negative quadratic (Ca = a + t − t2) function and had a maximum, which was variable. The Ca maximum concentration during decomposition was positively related to initial Ca concentration both within and among species. Separate linear relationships based on species were combined into one, in common for all investigated species and genera (R2 = 0.914, n = 63, p < 0.001). Limit values for decomposition were positively related to maximum Ca concentration at p < 0.05 with separate functions for pine and spruce litter. Calcium net release started directly after the incubation and was linear to accumulated mass loss of litter, giving a slope coefficient for each study. The net release rates were linear to initial Ca concentration both within and across species/genera. All studies combined gave a negative linear relationship (R2 = 0.894, n = 67, p < 0.001).

Pinewood nematode (Bursaphelenchus xylophilus) mortality was investigated after ultrasonic treatment at 20 and 40 kHz frequency. Experiments were conducted with infected small wood specimens that were ultrasonically treated for 1, 3, 5 and 7 hours and two variable temperature conditions, namely, a gradually increasing from ambient to a maximum of 70oC and a decreasing from ambient to a minimum of 5oC. The results revealed that the ultrasonic treatment itself had no significant effect on the nematode mortality at the 5oC level, while at the 70oC level, considerable nematode mortality was observed in short time periods and at 7 hours of sonic exposure it reached 100%. Therefore, certain combinations of timing and frequency of ultrasonic waves and produced heat can be effective in killing pinewood nematodes thus resulting in phytosanitized wood.

Pinewood nematode (Bursaphelenchus xylophilus) mortality was investigated after ultrasonic treatment at 20 and 40 kHz frequency. Experiments were conducted with infected small wood specimens that were ultrasonically treated for 1, 3, 5 and 7 hours and two variable temperature conditions, namely, a gradually increasing from ambient to a maximum of 70oC and a decreasing from ambient to a minimum of 5oC. The results revealed that the ultrasonic treatment itself had no significant effect on the nematode mortality at the 5oC level, while at the 70oC level, considerable nematode mortality was observed in short time periods and at 7 hours of sonic exposure it reached 100%. Therefore, certain combinations of timing and frequency of ultrasonic waves and produced heat can be effective in killing pinewood nematodes thus resulting in phytosanitized wood.

Pinewood nematode (Bursaphelenchus xylophilus) mortality was investigated after ultrasonic treatment at 20 and 40 kHz frequency. Experiments were conducted with infected small wood specimens that were ultrasonically treated for 1, 3, 5 and 7 hours and two variable temperature conditions, namely, a gradually increasing from ambient to a maximum of 70oC and a decreasing from ambient to a minimum of 5oC. The results revealed that the ultrasonic treatment itself had no significant effect on the nematode mortality at the 5oC level, while at the 70oC level, considerable nematode mortality was observed in short time periods and at 7 hours of sonic exposure it reached 100%. Therefore, certain combinations of timing and frequency of ultrasonic waves and produced heat can be effective in killing pinewood nematodes thus resulting in phytosanitized wood.

Pinewood nematode (Bursaphelenchus xylophilus) mortality was investigated after ultrasonic treatment at 20 and 40 kHz frequency. Experiments were conducted with infected small wood specimens that were ultrasonically treated for 1, 3, 5 and 7 hours and two variable temperature conditions, namely, a gradually increasing from ambient to a maximum of 70oC and a decreasing from ambient to a minimum of 5oC. The results revealed that the ultrasonic treatment itself had no significant effect on the nematode mortality at the 5oC level, while at the 70oC level, considerable nematode mortality was observed in short time periods and at 7 hours of sonic exposure it reached 100%. Therefore, certain combinations of timing and frequency of ultrasonic waves and produced heat can be effective in killing pinewood nematodes thus resulting in phytosanitized wood.

Mountain meadows provide a number of ecosystem services, including sequestering carbon, storing and regulating the release of water, and maintaining biodiversity. However, as with other grassland systems, many meadows are currently experiencing woody plant encroachment. In my first chapter, I used a landscape scale survey of mountain meadows in the central Sierra Nevada to quantify the extent of conifer encroachment, the density of encroaching conifers, and determine if synchronous temporal patterns of encroachment existed. By examining overall encroachment density among 310 meadows in the central Sierra Nevada, I found that essentially all high elevation meadows, up to the krummholz vegetation zone near treeline, have some degree of encroachment. Using natural variation in physical parameters among meadows, as well as variation in climatic conditions since the early 1900s, I was able to identify conditions conducive to conifer recruitment and/or survival. When I correlated annual recruitment with climatic conditions since 1930, conditions during the year of germination were unimportant with success instead depending on conditions during a 3-year seed production period and a 6-year seedling establishment period. Applying a temporal model based on climate during both seed production and seedling establishment periods to downscaled output from four global climate models indicates that the average meadow will convert to forest by the end of the 21st century. Given the ubiquitous nature of conifer encroachment in the central Sierra Nevada, in my second chapter I explored important life stages driving encroachment and the environmental factors influencing each. Using a 4-year study of 30 meadows in Yosemite National Park, I examined seed availability, germination, establishment, and adult survival. I found that seed was abundant throughout most of the interior of the meadows. Germination and seedling emergence showed high interannual variability, and locations with new g

Effects of stand type on ground lichen height and species richness in boreal forests. P. contorta as an alternative to P. sylvestris in terms of providing a suitable habitat Maria Johansson Abstract Lichen-rich forests are essential to reindeer but up to 50 % of the lichen-rich areas in Sweden have been lost since the 1950s. Ground lichens thrive in pine-heaths and with an increasing area of plantations of the non-native tree species Pinus contorta, as an alternative to the native P. sylvestris, it is important to investigate if P. contorta can provide such an optimal habitat to ground lichens. The purpose of this study was to assess if forest characteristics, such as tree density, canopy cover and production capacity, affect the abundance and growth of five lichen species (Cladonia rangiferina, C. arbuscula/mitis, C. stygia, C. stellaris and Cetraria islandica) and whether these characteristics differ between forests dominated by P. contorta and forests dominated by P. sylvestris. Fieldwork was conducted in Norrbotten and Västerbotten on sample plots previously used by the Swedish National Forest Inventory (SNFI). The statistical analysis was based on data collected from 22 sample plots, 11 of each forest type, visited during July and September 2015. No statistical significant differences were found between forest characteristics of the two forest types, and none of the forest characteristics were found to relate to lichen height. Forest age did not seem to have an effect on ground lichens, while both canopy cover and production capacity were found to negatively relate to the proxy for lichen biomass as well as the abundance of the most common lichen species, C. rangiferina and C. arbuscula/mitis. The result suggests that a shadier canopy as well as a higher production capacity contributes to a reduced distribution of ground lichens. Keywords: Ground lichens, Pinus contorta, Pinus sylvestris, forest characteristics, forestry, reindeer husbandry

As an environmentally friendly alternative to chemical treatment, this research aimed to establish whether dielectric heating at high frequency of infested lodgepole pine (Pinus contorta) boards and logs, obtained from the mountain pine beetle devastated forests of British Columbia, can result in wood free of living fungi, nematodes and insects. The sample set contained 230 boards, 50x150 and 50x100 mm2 in cross-section and 20 logs, 200-300 mm in diameter; all tested specimens were roughly one meter long. The intention was to test the efficiency of two temperature/time combinations: 56ºC for 30min and 60ºC for 15min that were identified in past works as effective phytosanitary combinations. Data showed that both permutations eradicated all infestation levels and types. The electric field power density per treatment cycle ranged from 23 to 50 kW/m3 and the total heating cycle varied from 42 to 116 minutes for all pest and wood type combinations tested.

As an environmentally friendly alternative to chemical treatment, this research aimed to establish whether dielectric heating at high frequency of infested lodgepole pine (Pinus contorta) boards and logs, obtained from the mountain pine beetle devastated forests of British Columbia, can result in wood free of living fungi, nematodes and insects. The sample set contained 230 boards, 50x150 and 50x100 mm2 in cross-section and 20 logs, 200-300 mm in diameter; all tested specimens were roughly one meter long. The intention was to test the efficiency of two temperature/time combinations: 56ºC for 30min and 60ºC for 15min that were identified in past works as effective phytosanitary combinations. Data showed that both permutations eradicated all infestation levels and types. The electric field power density per treatment cycle ranged from 23 to 50 kW/m3 and the total heating cycle varied from 42 to 116 minutes for all pest and wood type combinations tested.

Mountain meadows provide a number of ecosystem services, including sequestering carbon, storing and regulating the release of water, and maintaining biodiversity. However, as with other grassland systems, many meadows are currently experiencing woody plant encroachment. In my first chapter, I used a landscape scale survey of mountain meadows in the central Sierra Nevada to quantify the extent of conifer encroachment, the density of encroaching conifers, and determine if synchronous temporal patterns of encroachment existed. By examining overall encroachment density among 310 meadows in the central Sierra Nevada, I found that essentially all high elevation meadows, up to the krummholz vegetation zone near treeline, have some degree of encroachment. Using natural variation in physical parameters among meadows, as well as variation in climatic conditions since the early 1900s, I was able to identify conditions conducive to conifer recruitment and/or survival. When I correlated annual recruitment with climatic conditions since 1930, conditions during the year of germination were unimportant with success instead depending on conditions during a 3-year seed production period and a 6-year seedling establishment period. Applying a temporal model based on climate during both seed production and seedling establishment periods to downscaled output from four global climate models indicates that the average meadow will convert to forest by the end of the 21st century. Given the ubiquitous nature of conifer encroachment in the central Sierra Nevada, in my second chapter I explored important life stages driving encroachment and the environmental factors influencing each. Using a 4-year study of 30 meadows in Yosemite National Park, I examined seed availability, germination, establishment, and adult survival. I found that seed was abundant throughout most of the interior of the meadows. Germination and seedling emergence showed high interannual variability, and locations with new g

As an environmentally friendly alternative to chemical treatment, this research aimed to establish whether dielectric heating at high frequency of infested lodgepole pine (Pinus contorta) boards and logs, obtained from the mountain pine beetle devastated forests of British Columbia, can result in wood free of living fungi, nematodes and insects. The sample set contained 230 boards, 50x150 and 50x100 mm2 in cross-section and 20 logs, 200-300 mm in diameter; all tested specimens were roughly one meter long. The intention was to test the efficiency of two temperature/time combinations: 56ºC for 30min and 60ºC for 15min that were identified in past works as effective phytosanitary combinations. Data showed that both permutations eradicated all infestation levels and types. The electric field power density per treatment cycle ranged from 23 to 50 kW/m3 and the total heating cycle varied from 42 to 116 minutes for all pest and wood type combinations tested.

As an environmentally friendly alternative to chemical treatment, this research aimed to establish whether dielectric heating at high frequency of infested lodgepole pine (Pinus contorta) boards and logs, obtained from the mountain pine beetle devastated forests of British Columbia, can result in wood free of living fungi, nematodes and insects. The sample set contained 230 boards, 50x150 and 50x100 mm2 in cross-section and 20 logs, 200-300 mm in diameter; all tested specimens were roughly one meter long. The intention was to test the efficiency of two temperature/time combinations: 56ºC for 30min and 60ºC for 15min that were identified in past works as effective phytosanitary combinations. Data showed that both permutations eradicated all infestation levels and types. The electric field power density per treatment cycle ranged from 23 to 50 kW/m3 and the total heating cycle varied from 42 to 116 minutes for all pest and wood type combinations tested.

The aim of this paper is to evaluate relationships between decomposition rates of Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta var. contorta) needle litter in the late stage of decomposition (>30% accumulated mass loss), and the progressively changing concentrations of manganese (Mn), nitrogen (N), and acid unhydrolyzable residue (AUR), as well as mean annual temperature (MAT) and mean annual precipitation (MAP). Using available long-term decomposition studies on pine needle litter in a climate gradient in Sweden, we calculated annual mass loss and related to concentrations of Mn, N, and AUR at the start of each one-year period as well as to MAT and MAP. We investigated these relationships for (i) all data on annual mass loss combined and (ii) annual mass loss for five different decomposition categories as defined by accumulated mass loss. We found highly significant, negative, and dominant relationships between annual mass loss and N (R2=0.39) and AUR (R2=0.39), a slight but significant positive relationship to Mn (R2=0.08) and a significant negative relationship to MAT (R2=0.06). The relationships were dynamic, and changed with accumulated mass loss. The rate-dampening effect of N decreased to be a rate-enhancing effect at c. 60-80% accumulated mass loss. A similar trend was found for AUR, becoming rate-enhancing at 70-80% accumulated mass loss. For Scots pine needle litter the effect of MAT on mass loss decreased with increasing accumulated mass loss and changed to a rate-dampening effect at c. 50-70% accumulated mass loss. Mn showed a stimulating effect on mass loss rate in all categories whereas MAP showed no effect in this mainly boreal climatic gradient. The current approach indicates a method for detailed studies of rate-regulating factors for litter decomposition.

Det främmande trädslaget P. contorta (Pinus contorta) infördes storskaligt till Sverige på 1970-talet i syfte att motverka en befarad virkessvacka under 2000-talet. Idag finns uppskattningsvis 600 000 ha contortaskogar i Sverige och delar av dessa arealer närmar sig gallrings- och avvecklingsläge. För Holmen Skog AB som initierade detta examensarbete utgörs 6 % av det totala virkesförrådet av P. contorta. Alltsedan början av det storskaliga bruket av P. contorta i Sverige har trädens utveckling och tillväxt följts, men kunskapen om hur den biologiska mångfalden utvecklas i contortabestånd saknas fortfarande till stor del. Stora arealer som domineras av P. contorta tillsammans med omfattande stormskador på P. contorta har aktualiserat frågan om vilken naturhänsyn som ska lämnas i bestånd som ska avvecklas eller gallras. Det är också angeläget att försöka utreda vilka åtgärder som kan vidtas för att värna om den biologiska mångfalden i dessa skogar. Examensarbetet syftade till att beskriva hur hänsynsplaneringen lämpligen utformas i contortabestånd, främst i bestånd som närmar sig planerad gallring och avveckling. Målet var att få fram ett underlag till riktlinjer för naturhänsyn på arealer som domineras av P. contorta. Studien har bestått av två delar: fältinventering och litteraturstudier. Fältinventeringsmomentet utfördes i distrikt Delsbo, Hälsingland i syfte att undersöka förekomsten av naturvärden i contortabestånd. Litteraturstudien visade att det är samma krav på naturhänsyn i contortadominerade bestånd och bestånd dominerade med inhemska trädslag enligt SVL (Svensk skogsvårdslagsstiftning) och FSC-standarden. Det finns däremot lagar och rekommendationer som specifikt berör anläggning av contorta på beståndsnivå och landskapsnivå. Regleringarna av P. contorta är inte så utförliga i dagsläget, men kommer troligen bli mer omfattande vid nästa revidering av SVL och FSC-standarden. Resultatet av fältinventeringen visar att naturvärden finns i contortabestånd och a, The non-native lodgepole pine (Pinus contorta) was introduced on a large scale in Sweden in the 1970s to counter an anticipated timber dip in the 2000s. Sweden currently holds 600 000 ha of lodgepole pine dominated forests and parts of those areas are approaching the thinning- and clear felling stages. Holmen Skog AB, the industrial forest owner which initiated this thesis, has a holding of lodgepole pine that represents 6% of their total standing timber volume. Since the beginning of the extensive use of lodgepole pine, it has been possible to follow tree development and volume growth, but knowledge about the development of biodiversity in lodgepole pine forests is still limited. The dominance of this tree species over large areas in addition to extensive storm damage has raised the question of which environmental consideration is suitable when stands are harvested or thinned. It is also essential to explore the development of biodiversity in lodgepole pine dominated stands and how biodiversity can be protected by active measures. This thesis aimed to describe how conservation planning is suitably designed in lodgepole pine dominated stands, mainly in stands that are approaching the time of thinning or final felling. The goal is to obtain a foundation for the formulation of guidelines for environmental considerations in such stands. The study consisted of two parts: field inventory and literature studies. The field inventory was carried out in district Delsbo, Hälsingland in order to investigate the occurrence of high conservation values in lodgepole pine dominated stands. The literature study showed that it is the same requirements for environmental consideration in lodgepole pine stands and stands dominated by indigenous tree species according to SVL (The Swedish Forestry Act) and the Swedish FSC-standard. However, there are laws and recommendations concerning establishment of lodgepole at stand level and landscape level. The regulations of P. contorta are not de

Mountain pine beetle (Dendroctonus ponderosae) is an important disturbance agent in Pinus ecosystems of western North America, historically causing significant tree mortality. Most recorded outbreaks have occurred in mid elevation lodgepole pine (Pinus contorta). In warm years, tree mortality also occurs at higher elevations in mixed species stands. Mountain pine beetle's relative preference for and performance in Pinus species that either commonly or less frequently encounter this insect has received little direct testing. Further, knowledge of the relative proportions of secondary compounds, which can differ among Pinus species and play important roles in attack rates and outcomes, is important to understanding host suitability. We monitored mountain pine beetle attacks, adult emergence timing and reproductive capacity in lodgepole and whitebark (Pinus albicaulis) pines growing in mixed stands at relatively high elevation. Phloem monoterpene chemistry of trees prior to and during attack was compared within and between species. Although beetles attacked lodgepole pine more frequently, lodgepole pines also resisted attacks more frequently. Overall, there were equal numbers of lethal attacks between species. Brood production and adult emergence timing did not differ between tree species. The relative composition of secondary compounds differed by tree species, although both species contained compounds that affect mountain pine beetle attack and reproductive success., SCOPUS: ar.j, FLWOA, info:eu-repo/semantics/published

Den här studien är en uppföljning av föryngringsresultatet efter maskinell sådd av contorta ( Pinus contorta Dougl. var. latifolia Engelm.) i Härjedalen. Efter tre växtsäsonger uppgick det totala antalet såddplantor till 3 700 per ha och antalet huvudplantor uppgick till 1 800 per ha. Andelen nollytor uppgick till 2 %. Det var ingen skillnad i föryngringsresultat mellan låg och hög altitud. Generellt gav maskinell sådd av contorta ett tillfredsställande föryngringsresultat. På mindre bördig mark var såväl det totala antalet såddplantor som antalet huvudplantor högre än på bördigare mark., Mechanical regeneration by seeding of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in the province of Härjedalen in Sweden was studied. After three growing seasons the total number of seedlings were 3 700 per ha and the number of main seedlings were 1 800 per ha. 2% of the sample plots had no plants within 3 m. No difference could be found between objects on high and low altitudes. In general mechanical seeding gave satisfactory regeneration. On low fertile soils the total number of seedlings as well as the future main seedlings was higher than on more fertile soils.

Den här studien är en uppföljning av föryngringsresultatet efter maskinell sådd av contorta ( Pinus contorta Dougl. var. latifolia Engelm.) i Härjedalen. Efter tre växtsäsonger uppgick det totala antalet såddplantor till 3 700 per ha och antalet huvudplantor uppgick till 1 800 per ha. Andelen nollytor uppgick till 2 %. Det var ingen skillnad i föryngringsresultat mellan låg och hög altitud. Generellt gav maskinell sådd av contorta ett tillfredsställande föryngringsresultat. På mindre bördig mark var såväl det totala antalet såddplantor som antalet huvudplantor högre än på bördigare mark., Mechanical regeneration by seeding of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in the province of Härjedalen in Sweden was studied. After three growing seasons the total number of seedlings were 3 700 per ha and the number of main seedlings were 1 800 per ha. 2% of the sample plots had no plants within 3 m. No difference could be found between objects on high and low altitudes. In general mechanical seeding gave satisfactory regeneration. On low fertile soils the total number of seedlings as well as the future main seedlings was higher than on more fertile soils.

Forest trees exhibit a remarkable range of adaptations to their environment, but as a result of frequent and long-distance gene flow, populations are often only weakly differentiated. Lodgepole and jack pine hybridize in western Canada, which adds the opportunity for introgression through hybridization to contribute to population structure and (or) adaptive variation. Access to large sample size, high density SNP datasets for these species would improve our ability to resolve population structure, parameterize introgression, and separate the influence of demography from adaptation. To accomplish this, 454 transcriptome reads for lodgepole and jack pine were assembled using Newbler and MIRA, the assemblies mined for SNPs, and 1536 SNPs were selected for typing on lodgepole pine, jack pine, and their hybrids (N = 536). We identified population structure using both Bayesian clustering and discriminate analysis of principle components. Introgressed SNP loci were identified and their influence on observed population structure was assessed. We found that introgressed loci resulted in increased differentiation both within lodgepole and jack pine populations. These findings are timely given the recent mountain pine beetle population expansion in the hybrid zone, and will facilitate future studies of adaptive traits in these ecologically important species.

Understanding the physical and genetic structure of hybrid zones can illuminate factors affecting their formation and stability. In north-central Alberta, lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia) and jack pine (Pinus banksiana Lamb) form a complex and poorly defined hybrid zone. Better knowledge of this zone is relevant, given the recent host expansion of mountain pine beetle into jack pine. We characterized the zone by genotyping 1998 lodgepole, jack pine, and hybrids from British Columbia, Alberta, Saskatchewan, Ontario, and Minnesota at 11 microsatellites. Using Bayesian algorithms, we calculated genetic ancestry and used this to model the relationship between species occurrence and environment. In addition, we analyzed the ancestry of hybrids to calculate the genetic contr

Over the past 40 years 600 000 ha of lodgepole pine (Pinus contorta ssp. latifolia (Engelm.) Critchf.) has been planted in Sweden (280 000 ha on SCA's forest land alone which represents about 15% of the company's total forest land area). In the early 70's SCA situated a number of experimental stands in order to investigate different aspects of the exotic tree, primarily growth rate. To be able to compare the two species plots with scots pine (Pinus sylvestris L.), this species was also planted at the same time and under the same conditions. A number of questions should always be raised when exotic species are introduced in an ecosystem. Invasiveness, the pathogen situation and purely ethical issues should be discussed. One of the limiting factors of the lodgepole pine's invasiveness is its serotinous cones. Nevertheless has a certain self-spread still been shown to occur in the Swedish forest. The serotinous cones of the lodgepole pine are an evolutionary adaption to forest fire. In these cones it accumulates a great number of seeds in order to be released after the next fire. In addition to these cones there are a few cones that are able to spread the seed without heat. This makes the culture populations of lodgepole pine and their close environment is subjected to continuous exposure of viable seeds. The intention of this report is to investigate the potential of self-spread and establishment of P. contorta beyond the bounds of the cultural stands in northern Sweden. The establishment ability of the lodgepole pine is influenced by several habitat characteristics (such as vegetation, altitude, latitude, soil moisture). In the autumn of 2011 a field study was conducted with the intention of collecting suitable data in order to analyze these characteristics. The studies were carried out on 20 of SCA's trial facilities. These are located between 120-510 meters above sea level and in the range of 62° 12' N and 66° 11' N. Similar studies were carried out in 2000 and tho, Under de senaste 40 åren har det planterats ca 600 000 ha contortatall (Pinus contorta ssp. latifolia (Engelm.) Critchf.). Enbart på SCA Skogs marker finns 280 000 ha vilket motsvarar ca 15 % av bolagets totala skogsmarksinnehav. SCA lade i början av 70-talet ut ett 20-tal försöksbestånd i syfte att göra uppföljningar av contortatallens utveckling. För att kunna jämföra arterna finns även parceller med svensktall (Pinus sylvestris L.) i dessa lokaler. Införandet av en exot i ett ekosystem väcker frågor. Invasivitet, patogensituation och rent etiska frågor bör besvaras. Vad gäller contortatall är dess serotina kottar en begränsande faktor för dess virulens. Dock har det visat sig att en viss självspridning ändå förekommer i det svenska skogslandskapet. Vid sidan av de kådindränkta kottarna (där, i väntan på nästa skogsbrand, frön bevaras under flera årtionden) finns kottar som har möjlighet att sprida frön utan att utsättas för värme. Detta gör att kulturbestånden av contortatall och deras nära omgivning utsätts för en kontinuerlig exponering av grobara frön. Denna rapport ämnar utreda contortatallens förutsättningar att etablera sig och sprida sig utanför de ursprungliga kulturerna i norra Sverige. Frågeställningen berör olika ståndortsegenskaper (exempelvis markvegetation, höjd över havet, latitud, markfuktighet) och deras inverkan på contortatallens etableringsförmåga. För att kunna besvara detta utfördes en fältstudie under hösten 2011 då datainsamlingen gjordes på 20 av SCA Skogs försökslokaler i Norrland vars lokalisering var inom spannen: 120-510 m.ö.h. och 62° 12' N-66° 11' N. Dessa lokaler besöktes år 2000 då en liknande undersökning utfördes. Nu gavs möjlighet till jämförelser av självföryngringssituationen i direkt anslutning till de då 30-åriga bestånden tio år senare. Resultaten visar på den stora betydelsen av störning för plantornas etablering. Endast 14 % av contortaplantorna som hittades fanns på mark som ej störts på något sätt. Detta kan jämföras m

The Lodgepole pines susceptibility to Heterobasidion spp. was investigated in three parts of this study. In the first part, discs from freshly cut stumps were collected and analyzed to see if the fungi can spread and grow naturally in Lodgepole pine stands. In the second part, root samples were collected from Lodgepole pines planted in former infected Norway spruce stands to see if the fungi can spread through root contacts. For the third part, new stumps was created and artificially infected with spores of both the S‐type (H. parviporum) and the P‐type (H. annosum) of the fungi to find out if the Lodgepole pine is susceptible to them. None of the stumps from recently thinned stumps were infected and it was later discovered that these stands in fact were thinned one and two years ago which probably has had influence on the result. Infected roots were found on four out of 15 trees that were expected to be infected and totally 17 % of all sampled trees, with and without symptoms, were infected. On all stumps that were artificially infected with the P‐type and all but one stump that were artificially infected with the S‐type, infections were found 51 days after the time of infection. These results indicates that the Lodgepole pine is susceptible to both types of the fungi and that it can be infected through root contacts which means that Heterobasidion spp. may be a threat to the Lodgepole pines. Because of this, new management methods such as stump treatment during thinning, stump removal and a better habitat adaptation when re‐planting stands with Lodgepole pine might be necessary.

We compared the plant understorey between stands of introduced Pinus contorta and native P. sylvestris in boreal northern Sweden using a chronosequence of 24 paired stands of P. contorta or P. sylvestris. We located one 1000 m2 sample plot in each stand in which we recorded tree variables, number of vascular plant and lichen species, and cover of the understorey of each of the groups vascular plants, bryophytes and lichens. We tested for differences between the two chronosequences and assessed relationships between the understorey and stand variables. Tree variables did not differ between stands but stands of P. contorta had more than three times greater percent ground cover of needle litter compared to stands of P. sylvestris. Naturally regenerated individuals of P. contorta occurred in five out of 12 stands of P. contorta older than 25 years. The understorey was similar between stand types in terms of species richness, cover, and species composition but the entire species pool was larger for stands of P. sylvestris than for stands of P. contorta. Thirty-eight species were only found in stands of P. sylvestris; the corresponding figure for stands of P. contorta was six species. Shade-intolerant understorey species were disfavoured in stands of P. contorta. The development at the stand level of understorey (vascular plant and lichen) species richness and cover over time was similar between stand types. In both types of stands, the number of lichen species and the percent ground cover of lichens and bryophytes increased with stand age; the corresponding values for vascular plant species did not. The results propose a more homogeneous flora in stands of P. contorta compared to stands of P. sylvestris, suggesting lower understorey species richness at the landscape scale. The larger shading effect of needles in the canopy and on the ground in stands of P. contorta, which is supposed to imply less habitat variation, might contribute to this difference.

The Swedish Cellulosa Companiy, SCA, has today 280 000 ha planted with lodgepole pine (Pinus contorta var. latifolia) ("C") which is equivalent to 14 % of its total forest area. Exotic lodgepole pine has in previous experimental stands shown a superior growth than the native Scots pine (Pinus sylvestris L.) ("S").But also the comparison could be questioned because stand histories were was unknown and also differences in age between C and S existed. To establish a better comparison between the coniferous species initiated SCA in 1970 new experimental stands where C and S were planted under the same conditions. These experimental stands were measured 1979, 1984 and 1991 and the data were used for development of growth models. The purpose of this study was to follow up growth- and saw timber quality development in SCA´s experimental stands with C and S. On the basis of previous comparisons of the species the following hypothesis were formulated: • The total growth is up till now 50 % superior in C than in S • The dominant height in studied stands is developing according to height curves both for C and S • The "future stems" have almost the same saw timber quality in C and S Nine experimental stands from Åsarna in Jämtlad to Vilhelmina in Lapland (middle north Sweden) were visited in autumn 2007. In every experimental stand ten permanent plots were examined, five in C stands and five in S. On those plots all trees with dbh > 5 cm were callipered and height was measured on sample trees. About 20 "potential final cut trees" were appointed within a radius of 10 m and the criterion for those trees was that they visually showed on good saw timber quality. The total growth, including thinned trees for C was as a mean value 53 % higher than for S. The average growing stock was 179 m3sk/ha in C and 134 m3sk/ha in S. The development of C follows the yield models as predicted. Until 1991 C had a higher survival rate than S. Three C stands were tinned (9064, 9066 and 9072) in the, SCA har idag 280 000 ha skogsmark planterad med contorta (Pinus contorta var. Latifolia) (”C”) vilket motsvarar ca 14 % av det totala skogsmarksinnehavet. Contortan har i tidigare försöksplanteringar visat på en högre tillväxt än tall (Pinus sylvestris L.) (”S”) men jämförelserna kunde kritiseras eftersom tallbeståndens historik var okänd och åldersskillnader mellan tall och contorta förekom. För att få en bättre jämförelse mellan contorta och tall lade SCA ut ett antal försöksodlingar i början av 1970 talet där contorta och tall odlas under lika villkor. Dessa bestånd är inmätta tre gånger tidigare och ligger till grund för produktionsmodeller. Syftet med detta arbete var att följa upp och jämföra produktion och kvalitetsutveckling i SCA:s odlingsförsök med contorta och tall. På grundval av tidigare contortastudier formulerades följande hypoteser: • Totalproduktionen har hittills varit ca 50 % högre i C än i S • Övre höjden har utvecklats enligt SI-kurvorna för både C och S • Framtidsträden har nästan lika god timmerkvalitet hos C som hos S Nio lokaler besöktes från Åsarna i Jämtland till Vilhelmina i Lappland under hösten 2007. I varje lokal fanns tio permanenta försöksytor, fem i contortabeståndet och fem i tallbeståndet. På varje provyta klavades alla träd med dbh > 5 cm och höjd mättes på provträden. Cirka 20 potentiella slutavverkningsträd utsågs inom en radie på 10 meter. Kriteriet för dessa träd var att de bedömdes vara mest lämpade för god tillväxt och timmerproduktion (vitala, raka, sprötoch klykfria). På framtidsträden bedömdes kvalitet uppdelat på tre bedömningsgrunder, krök, spröt och dubbeltopp. Resultaten visar att contortan har under ca 40 år i snitt inklusive gallring och naturlig avgång producerat 53 % mer än tallen. Den stående volymen i contortabestånden var i snitt 179 m3 sk/ha och i tallbestånden 134 m3 sk/ha. Fram till 1991 hade contortabestånden högre överlevnadstakt än tallbestånden. Tre contortabestånd var gallrade (9064 9066 and 9072) och

The aim of this study is to describe a number of type stands of lodge pole pine in Norrbotten with respect on stem volume and total biomass. Further questions to answer is if there is stand characteristics that make the stands more suitable for pulpwood in early thinning, or if it is better to apply whole tree harvest. The study shall also give an indication if bio energy can be an economical interesting alternative for Sveaskog. Sampled trees represented the variation in the different stands. Five trees were selected from each stand to represent that stand. Stem volume and biomass (kg dry weight (DW) per hectare) for each fraction was calculated. In total 20 trees were sampled for destructive above ground biomass estimation. The study was done i Morjärv, in the province of Norrbotten, Northern Sweden. It was concluded, that there is a strong connection between stem volume and dry weight (DW), which interpret that stem density does not vary between the different stands. There was a small variation between stem volume and diameter in breast height (DBH) between the different stands. The results interpret that the weight of the crown is the same for trees with the same diameter, while the stem weight in relation to diameter vary between stands. The explanation seems to be that the stem forms vary between stands. For that reason, the additional harvest that could be achieved by whole tree harvest compared to traditional harvest varied between 61-85%. It is clear, that the pattern of allocation vary in different types of lodge pole pine stands. This study indicated that whole tree harvest for bio fuel energy could be more profitable in early thinning. Further, existing volume functions for lodge pole pine seems to work well to estimate stem volume. For estimating different fractions from lodge pole pine, more work need to be done to develop biomass functions for this tree species., På Sveaskogs marker finns ca 60 000 ha contortaskog varav ca 32 000 hektar av dessa finns i Norrbotten. Stora arealer av dessa skogar börjar växa in i gallringsmogen ålder men den praktiska erfarenheten av beståndsbehandling är fortfarande liten. Syftet med denna studie är att beskriva ett antal typbestånd av contorta i Norrbotten med avseende på stamvolym och totalbiomassa och om det finns beståndskaraktärer som gör bestånden mer lämpliga att skörda som massaved i första gallring, eller om man ska tillämpa träddelsavverkning. Studien skall även ge en indikation på om uttag av biobränsle kan vara ett ekonomiskt intressant alternativ för Sveaskog. Contortabestånden som studerats var av varierande kvalitet, från mycket fina contorta -bestånd till riktigt risiga bestånd för att spegla variationen som återfinns i verkligheten. Fem träd valdes ut i varje bestånd och dessa fick representera lokalen för bestämning av stamvolym och biomassans olika fraktioner och dess storlek uttryckt i kg torrvikt per hektar. Det fanns ett starkt samband mellan uppmätt stamvolym och stammens torrvikt vilket tyder på att stammens densitet inte varierar mellan de olika lokalerna. Sambandet mellan stamvolym och brösthöjdsdiameter varierade något mellan de olika försökslokalerna. Resultaten tyder på att kronans vikt är densamma för träd med samma diametrar medan stammens vikt i förhållande till diametern varierar mellan lokalerna. Förklaringen tycks ligga i att stamformen varierade mellan lokalerna. Av den anledningen blev merskörden som kunde uppnås vid träddelsavverkning jämfört med att bara tillvarata stamveden olika mellan de olika lokalerna 61-85%. Beräkningarna som är gjorda tyder på att ett energiuttag kan löna sig bättre i första gallring av contorta än konventionellt uttag av massaved. Kalkylexemplet visar dock på att det är viktigt att karaktärisera bestånden med avseende på såväl möjlig skörd av stamved som totalbiomassa för energiändamål innan åtgärdsbeslut fattas. Med de förutsätt

Several lines of evidence support the hypothesis that local populations of red crossbills (Loxia curvirostra complex) enter into a predator-prey arms race with lodgepole pine (Pinus contorta latifolia) in the absence of competing pine squirrels (Tamiasciurus hudsonicus). Nevertheless, the alternative hypotheses that neutral evolution or factors other than squirrels have caused crossbill population differentiation have not been thoroughly tested. We compared crossbill and pine cone morphology between island populations where squirrels are absent or present, and mainland sites where squirrels are present, in order to distinguish among these hypotheses. All comparisons supported an effect of squirrel absence, not island status, on crossbill and cone morphology. Hence our results provide further evidence that strong localized coevolutionary interactions in a geographic mosaic have driven adaptive population differentiation. In addition, vocal differentiation of crossbills was related to the absence of squirrels, but not to island status. As morphological and vocal differentiation is correlated with reproductive isolation in crossbills, the geographic mosaic of coevolution also seems to promote ecological speciation.