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<p> Statistical analyses between the relationship of tree-ring widths with variations in climate were used to examine the limiting climatic factors upon the growth rate of Picea mariana along the treeline and in hopes of reconstructing past climate. Tree-ring widths were used as a proxy measure of growth rates to establish the relationship of annual variances in temperature and precipitation on the growth rate of trees. Twelve tree cores were sampled from separate trees along the treeline northeast of Yellowknife, Northwest Territories. The trees, (with cores spanning 40 -160 years per tree), were compared to monthly and seasonal variations of both temperature and precipitations. A stepwise regression model was used to examine the climate-growth response. No climatic variables were found to illicit a general response pattern. The growth rate of trees along the treeline, northeast of Yellowknife do not appear to be dependent upon variations in the regional climate. Therefore, no climatic reconstructions were possible.</p> / Thesis / Bachelor of Arts (BA)

Tyrimų pagrindimas. Paprastoji eglė yra svarbi ūkinė rūšis Lietuvoje. Kilmių perkėlimas ir tolesnė selekcija gali ženkliai padidinti genetinę naudą gautiną iš p . eglės ūkinės paskirties medynų. Tuo tikslu, reikia informacijos apie genetinius skirtumus ir jų kitimo dėsningumus tarp p. eglės populiacijų perspektyviame introdukcijai Baltijos regione. Tyrimo tikslas- palyginti paprastosios eglės Baltijos regiono kilmių palikuonių adaptacinių, stiebo kokybės ir gyvybingumo požymių geografinio kintamumo dėsningumus bei kilmių perkėlimo ūkinę naudą bandomuosiuose želdiniuose. Objektas – 2001 m. įveisti paprastosios eglės Baltijos regiono kilmių palikuonių bandomieji želdiniai Kazlų Rūdos MMU (85 kilmės, po 50 kiekvienos kilmės medelių). Metodai – tyrimo metu buvo įvertintas medelių aukštis ir stiebo kokybė, nustatyta pumpurų sprogimo klasė, bei atlikta šių duomenų statistinė analizė. Rezultatai. Iš pietų į šiaurę perkeltų kilmių medeliai buvo aukštesni, geresnės stiebo kokybės ir vėliau pradėjo sezoninį augimą nei šiaurinių kilmių medeliai. Ypač mažu produktyvumu ir prasta stiebo kokybe pasižymėjo šiauriausios šiame bandyme pietų Suomijos kilmės, o šiaurinės Lenkijos kilmių medeliai produktyvumu lenkė vietinės kilmės medelius. Tai paaiškintina santykinai stipresniais šalnų pakenkimais, dėl ankstyvesnės šiauresnių kilmių sezoninio augimo pradžios ir mažesniu medeliu aukščiu dėl santykinai ankstesnės augimo pabaigos. Minėtų požymių geografinis kintamumas yra palaipsniui... [toliau žr. visą tekstą] / Background. Norway spruce is an imprint commercial forest tree specie sin Lithuanian. Provenance transfer and further breeding may markedly rise the benefit from commercial forests of Norway spruce,. For this purpose, there is a need of information on genetic variation and its geographical patters among Norway spruce provenances within the Baltic sea region of interest for introduction to Lithuania an don the benefit of the transfer itself. Objectives of the study are to compare the patterns of geographical variation among Baltic Norway spruce provenances in adaptive traits and to assess benefit of provenance transfer in the experimental plantation. The test. The study was carried out in an experimental plantation of Baltic Norway spruce provenances established in 2001 in Kazlu Ruda MMU (85 provenances of 50 trees each). Methods. Height, stem quality and stage of budburst in spring of the provenances were measured in the experimental plantation and statistical analysis methods were used to present the data. The results. The results showed that trees of the southern provenances were taller of better stem quality and later growth start in spring than trees of northern provenances. Trees of the most northern in this trial Finnish and Swedish provenances performed extremely poorly. Northern Polish provenances were more productive than the tree of the local origin. This result may be a consequence of spring frost damage of early flushing trees. The trees of northern... [to full text]

<p> In this thesis, the postglacial spread of three ecologically distinct species, Picea mariana (black spruce), Picea glauca (white spruce), and Pinus banksiana (jack pine), across the western interior of Canada are presented. The fossil pollen records from the sediments of thirteen lakes are used in reconstructing the population expansions of the three tree taxa. The objectives of this study are to examine temporal and spatial patterns in the growth of the populations and to determine if intraspecific and interspecific variations exist across a range of latitudes and elevations.</p> <p> Pollen accumulation rates (PAR) are calculated from pollen grain counts and sedimentation rates throughout the early-to mid-Holocene, and are used to represent the population level at the time of pollen deposition. Exponential equations are used to calculate population growth rates. Three dimensional diagrams (time, space, abundance) are constructed to illustrate the spread of the populations.</p> <p> The rates of population growth varied from south to north for all three species. Jack pine, on average had slower population growth rates, and its expansion across the region began over 3,000 years later than, and lasted approximately 1,000 years longer than the two spruce species. All three tree taxa experienced reduced rates of population growth at high elevation sites in the north. These variations are examined in light of the changing and static physical and botanical environmental conditions occurring during expansion.</p> / Thesis / Master of Science (MSc)

Population genetic analyses can provide information about both neutral and selective evolutionary processes shaping genetic variation. In this thesis, extensive population genetic methods were used to make inferences about genetic drift and selection in spruce species. In paper I we studied four species from the Qinghai-Tibetan Plateau (QTP): Picea likiangensis, P. purpurea, P. wilsonii and P. schrenkiana. Big differences in estimates of genetic diversity and Ne were observed in the more restricted species, P. schrenkiana, and the other more widely distributed species. Furthermore, P. purpurea appears to be a hybrid between P. likiangensis and P. wilsonii. In paper II we used Approximate Bayesian Computation (ABC) to find that the data support a drastic reduction of Ne in Taiwan spruce around 300-500 kya, in line with evidence from the pollen records. The split from P. wilsonii was dated to between 4-8 mya, around the time that Taiwan was formed. These analyses relied on a small sample size, and so in Paper III we investigated the impact of small datasets on the power to distinguish between models in ABC. We found that when genetic diversity is low there is little power to distinguish between simple coalescent models and this can determine the number of samples and loci required. In paper IV we studied the relative importance of genetic drift and selection in four spruce species with differing Ne: P. abies, P. glauca, P. jezoensis and P. breweriana. P. breweriana, which has a low Ne, exhibits a low fraction of adaptive substitutions, while P. abies has high Ne and a high fraction of adaptive substitutions. The other two spruce, however, do not support this suggesting other factors a more important. In paper V we find that several SNPs correlate with both a key adaptive trait (budset) and latitude. The expression of one in particular (PoFTL2) correlates with budset and was previously indentified in P. abies. These studies have helped characterise the importance of different population genetic processes in shaping genetic variation in spruce species and has laid some solid groundwork for future studies of spruce.

Bark beetle outbreaks are becoming more intense and severe when coupled with the effects of climate change. Engelmann spruce (Picea engelmannii) is one such species facing large-scale, epidemic spruce beetle outbreaks. Large-scale disturbances, such as beetle outbreaks, have major consequences for the future success of the ecosystem, thus highlighting the importance of understanding what promotes amplified outbreaks as well as their effects on future seedling establishment. Our research focused on two parts of a large-scale beetle outbreak: the mortality of spruce trees and the subsequent regeneration of seedlings. Our first study examined the timing of spruce mortality during an outbreak in order to identify the extent to which drought promotes host species mortality. Trees that are drought stressed have less resources to defend themselves against beetle attacks, however, the warmer temperatures associated with droughts also promote a more rapid population expansion of spruce beetles. We were specifically interested in determining the contribution that host drought stress plays during an epidemic outbreak. Our second study analyzed the patterns of regenerating seedlings with an aim to identify changes associated with the outbreak. Specifically, we were interested in how an epidemic outbreak changes the drivers of seedling establishment.

In Norway spruce there's a large natural variation in durability but knowledge about what is causing this variation is missing. In this thesis the focus were put into investigating how the water uptake ability was affected by the influence of heartwood versus sapwood and wood properties such as density and annual ring width. Liquid water permeability was checked trough a modified version of EN 927-5 and samples were also investigated trough the Mycologg Method. The wide grown wood with a coating system (a priming oil and alkyd or acrylate paint) absorbed less water than the narrow grown wood in the permeability test. The Mycologg test showed a clear difference between wide and narrow grown wood. Further research is necessary to examine the impact of wood properties when it comes to water uptake.

Norway spruce is one of two dominating species in Swedish forestry and the most economically important tree species in Sweden. In order to preserve the ability to adapt to a changing environment and to keep populations healthy, genetic diversity has to be preserved. When choosing a small number of individuals from a natural stand to establish a seed orchard the population size decrease. With only a small number of genetically different individuals the risk of inbreeding increase. Furthermore if many clones of the same tree are used in one seed orchard there is also an increased risk selfing. The aim of this study was therefore to investigate whether genetic diversity in Norway spruce differs between age groups and if this can be attributed to forestry practices. All sampling was done from a single location in Västerbotten, Sweden and the different age groups were chosen to represent stands not affected by the modern forest industry to recently planted forests. The chosen age groups are young (12-18 years), intermediate (30-45 years), and old (above 85 years). From each age group 150 individuals were sampled. With genomic microsatellite markers each individual was genotyped at eight simple sequence repeat (SSR) loci. Results show an overall high genetic diversity with an average expected heterozygosity (He) at 0.842 and low genetic differentiation with an average fixation index among populations (FST) of 0.003. The genetic diversity of each age group was also high (He 0.832 to 0.843) and the inbreeding coefficient ranged from 0.061 in the old group to 0.078 in the intermediate group. The pairwise FST value was highest between the old group and the young group but the differentiation was only 0.005 (P=0.001). An analysis of molecular variance also showed that only 0.34% of the total genetic variance was explained by differences among age groups. This study found little evidence for a decrease in genetic diversity due to forestry practices and revealed high genetic diversity and low differentiation between the age groups, indicating a healthy population.

Denna uppsats presenterar tre designförslag på samplanteringar med barrväxter i fokus. Designförslagen är gjorda till tre fiktiva platser med olika ståndort i växtzon 5, en liten entréplantering i västerläge med kalkhaltig jord, en mellanstor plantering i söderslänt med sandblandad jord och en parkplantering med fuktig jord med ett lågt pH-värde. Platserna är valda med tanken att läsarna ska kunna inspireras att använda barrväxter i olika typer av planteringar och trädgårdar. Till grund för växtvalen har gjorts en litteraturstudie inom området barrväxter, med fokus på barrväxters ståndort och hur de fungerar i samplanteringar med perenner och lignoser. Bakom designförslagen ligger även en idé om att hitta lite nya sätt att använda barrväxter, detta för att inte göra upprepningar av de skötselfria planteringarna med barrväxter som blev så oerhört populära på 70-talet och som delvis givit barrväxter ett dåligt rykte. Designförslagen presenteras i utförliga illustrationer och genom en processbeskrivning för att belysa designprocessens vägar och val, från början till slut.