Abstract Natural selection, mutation, recombination, demographic history and chance all have a role in evolution. In natural populations, the outcome of these forces is seen as adaptations, differences between geographic varieties, and as genetic diversity in populations—both at the phenotypic and molecular levels. In this thesis I wanted to examine the roles of the evolutionary forces shaping molecular genetic diversity in trees, with emphasis on a boreal conifer, Scots pine (Pinus sylvestris). Phylogeographic history and past population size changes have a dominant role in molecular diversity of P. sylvestris. The effect of the Last Glacial Maximum (37 000–16 000) was observed in the distribution of mitochondrial DNA variation. In contrast, nuclear DNA was not much affected by the last glacial period. Instead, more ancient demographic events that took place millions of years ago can still be observed in the variation of P. sylvestris nuclear DNA. Not much evidence of positive natural selection was found in pines or trees in general. This is in contrast to strong natural selection that is observed at the phenotypic level. Positive selection is difficult to prove, especially when the genome is still affected by demographic history. Mutation–drift equilibrium may rarely be reached in tree populations.

Betesskador kostar Sveriges skogsbruk stora summor varje år orsakade av älgbland annat. Vargens återkomst och mänsklig jakt har stor påverkan på älgpopulationen och trots en minskad älgstam så visade studier på att betesskadorna var oförändrade och till och med ökade. Studiens syfte var att utreda om man med hjälp av befintlig statistik från älgbetesinventeringar, avskjutningsstatistik för älg samt varginventering bekräfta att betesskadorna borde minskat i områden med vargrevir. Någon statistisk signifikans kunde inte bekräfta att betesskadorna minskade inom vargrevir och en trolig förklaring var stora mellanårsvariationer i älgbetesinventeringen samt för få variabler.Största anledningen till betesskador verkade mera bero på skogsbruket och skogens sammansättning och inte på hur mycket älg det fanns, trots stor predation och jakt så minskade inte betesskadorna.

Acetylation of wood is a modification technique that chemically alters the wood substance and enhances several properties of wood. The basic principle is to impregnate wood with acetic anhydride to react and replace OH-groups with acetyl groups in the wood cell wall. In this way, the hygroscopicity of the modified wood is significantly reduced resulting in increased dimensional stability and durability compared with unmodified wood.The objective of this work was to study finger-jointing of acetylated Scots pine (Pinus sylvestris L.) using a conventional melamine urea formaldehyde (MUF) adhesive. Two different types of acetylated pine specimens were investigated, acetylated pine sapwood (APS) and acetylated juvenile pine (AJP), the latter originating from young forest thinning trees (ca 20-30 years). The goal was to evaluate the bending strength, i.e. modulus of rupture (MOR), of such finger-jointed samples, in particular when the acetylated wood was combined with unmodified wood, in this case, Norway spruce (Picea Abies L. Karst) (US). The finger-jointing were performed at Moelven Töreboda by applying their existing industrial procedures. In total, five different of finger jointed sample groups were prepared combining the different specimens: APS-APS, AJP-AJP, US-US, APS-US, and AJP-US. Standardized procedures were used to determine the MOR of the finger-jointed samples, both unexposed at the factory condition state and after a water-soaking-drying cycle. In addition, the experiments also included determination of the moisture content (MC), density, and modulus of elasticity (MOE) (in bending along the grain) of the individual specimens.At the unexposed state, the APS-APS samples showed the highest MOR of 63,1 MPa, while those of the AJP-AJP showed the lowest value of 42,4 MPa. The corresponding values for the US-US, AJP-US and APS-US samples was 56,7, 47,5 and 46,9 MPa, respectively. In contrast to a typical wood failure for the US-US samples, a low amount of wood failure was observed in all cases involving the acetylated wood, indicating a low adhesive anchoring in the wood substrate at the finger-joint, although a surprisingly high strength was obtained for the APS-APS samples. A significantly lower MC content of 4,9 % and a remarkably low value of 1,7 %, was found for the APS and AJP, respectively, compared with 9,2% for the US. The significantly lower MC combined with an assumed increased hydrophobicity of the acetylated wood possible causes a less effective MUF-wood bonding, or adhesion, compared with that of the unmodified wood. Possible, so-called over penetration of the MUF resin in the acetylated wood could also be an explanation for the poor wood-adhesive anchoring. The MOE of the individual APS, AJP and US specimens was 12,6, 8,3 and 11,4 GPa, respectively, indicating a significantly lower mechanical performance of AJP, and hence also of finger-joints of AJP, despite its very low MC, possible due to a higher microfibril angle in the cell walls in juvenile wood compared with mature wood. No clear correlation was found between the MOR and density of the acetylated samples.For the samples exposed to a water-soak-drying cycle, the highest MOR, and lowest reduction of 14 % compared with the unexposed state, was obtained for the US-US samples, whereas all samples involving the acetylated wood showed a distinctly higher reduction. The MOR of the AJP-AJP and AJP-US samples were reduced with 47 % and 50 %, respectively, while the MOR of the APS-APS and APS-US samples were reduced with 43 % and 23 %, respectively. It should be emphasized, however, that after the standard drying-time, which was the same for all samples, the acetylated samples, compared with the untreated ones, did not dry out to the same level as for the dry unexposed state, i.e. the acetylated samples had a high MC of ca 30-40% in these MOR tests. This high MC level could be the main reason for the dramatic strength losses. Furthermore, a less efficient wood-MUF adhesion as well as the drying under acidic conditions may also be possible causes for the reduced bending strength of the finger-jointed samples with acetylated wood.

Forests are among the most important repositories of terrestrial biodiversity and provide a broad range of ecosystem services. During millennia, forests have changed, adapted and evolved under changing conditions. However, in the present century, forests are facing environmental changes at rates with no precedents. A major concern is the risk of declining forest genetic diversity, since genetic variation as the raw material underpinning adaptation is key in maintaining the resilience of forest ecosystems against environmental changes. Understanding the different processes responsible for developing and maintaining the genetic diversity of tree species is essential to better predict tree responses under new conditions. Therefore, this thesis aimed to determine how different forces interact to shape and maintain within and among population genetic diversity of Scots pine and what the implications are for conservation and management under forthcoming environmental conditions. From local to continental scales, I followed a multilevel approach, and found that (i) historic climate changes and geographical barriers have played an important role in shaping the extent and spatial distribution of current genetic diversity of Scots pine. Despite contemporary habitat reduction and fragmentation we found that (ii) high levels of neutral genetic diversity remain in the Scottish populations of Scots pine, with gene flow and specifically wind-driven gene flow dominating over genetic drift and preventing differentiation among the Scottish populations. However, (iii) considerable impacts in the spatial distribution of genetic variation have occurred as a consequence of intensive historical forest management practices. Furthermore, we found that (iv) substantial levels of adaptive genetic variation are present in the Scottish populations of Scots pine, likely a result of selective processes resulting from the different environments they live in, with highly heritable traits, although similar capacity for response through phenotypic plasticity to warming. The results of this thesis help to further disentangle the forces maintaining genetic diversity in one of most widespread conifers in the world, and improving predictions of likely range shifts and adaptation of the species in response to contemporary changes. The thesis provides some recommendations to conservation and management practices.

Tyrimų rezultate buvo nustatyti trako ir gyvosios dirvožemio dangos pokyčiai pušynuose po atvejinių kirtimų I atvejo Na, Nb, Nc, Lb augavietėse bei įvertinti pomiškio gausumo pokyčiai. Įvertinta gyvosios dirvožemio dangos įtaka paprastosios pušies savaiminukų gausumui po I kirtimų atvejo tirtose augavietėse. Įvertintos kirtaviečių ekologinės sąlygos pagal Elenbergo fitoindikacinės skalės indikatorines vertes skirtingose augavietėse. Nustatyta smiltyninio ir miškinio lendrūnų fitometrinių parametrų ir elementinės sudėties pokyčiai po atvejinių kirtimų I atvejo. Atliktais tyrimais nustatyti dirvožemio cheminių savybių pokyčiai. Palyginta plynųjų ir atvejinių kirtimų įtaka dirvožemio temperatūros ir drėgnio, mineralinio azoto, ir kvėpavimo intensyvumo pokyčiams. / Results of the research allowed determining the changes of undergrowth and ground vegetation in pine forest after the first step of shelterwood cuttings in Na, Nb, Nc and Lb sites and to evaluate the alterations of saplings abundance. The influence of ground vegetation on the abundance of Scotch Pine sapling after the first step of shelterwood cuttings in investigated sites was assessed. Ecological conditions of cutting sites in different soil sites were estimated according to Ellenberg’s indicator values for phytoindication. The alterations of morphometric indices and chemical composition of wood small-reed and rough small-reed after the first step of shelterwood cuttings were assessed. The changes of soil chemical characteristics were determined after investigation. The influence of clear cuttings and shelterwood cuttings on the alterations of soil moisture, temperature, mineral nitrogen and respiration intensity was compared.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2006. / Thesis documentation sheet inserted. Errata sheet inserted. Appendix reprints four papers and manuscripts co-authored with others. Includes bibliographical references. Issued also electronically via World Wide Web in PDF format; online version lacks appendix.

The usage of biofuel as well as wood fuel has increased in Sweden and all of Europe during recent decades, and there are several reasons to believe that this increase will continue. An important reason for this increase is that the environmental and climate problems caused by fossil fuels are becoming even more evident. By replacing fossil fuel with biofuel, the problem of emissions from, among others carbon dioxide and sulphur compounds can be alleviated. However, substitution requires in many cases high quality processed biofuel. An early stage in the processing of biofuel is drying. Previous work treats the possibility of drying wood fuel in an efficient and environmentally sustainable manner. This thesis studies the bed drying technique, conducted both experimentally and through modeling of the drying process. The experimental work is based on continuous temperature measurements in the fuel bed and provides characteristics of the drying zone that develops in the bed during drying. The character of the drying zone is affected by both the qualities of the fuel and the operating parameters, and is decisive regarding the possibility of making the drying more efficient, i.e. optimize the usage of energy and produce a fuel with low and homogeneous moisture content. A mathematical simulation model has been developed to increase the understanding of bed drying. The model is based on fundamental physical principles and is made up of five differential equations that describe vapor flow, air flow, the fuel’s moisture content, and the bed’s pressure and temperature. The modeling work complements the experimental work and a simulation of the temperature distribution, pressure and the drying zone’s dispersion is in agreement with the experimental result. The drying of wood can signify an environmental and human health risk, since volatile organic compounds (VOC) are emitted during drying. The thesis studies these emissions with regards to type and quantity. The measurements show that the majority of the emitted compounds from Norway spruce and Scots pine are volatile monoterpenes, but also that other compounds are emitted, especially higher terpenes. Further, major differences between how the compounds are emitted and the quantities of the emitted compounds from heartwood and sapwood are shown. There are also large differences between types of wood, i.e. spruce and pine. It can be stated that both emission rate and total amount of emitted compounds increase with an increase in temperature. To reduce VOC emissions, the drying temperature should be maintained low. To develop an efficient bed drying process for wood biofuels, additional parameters must be analyzed further and weighed against each other. Based on the experimental method and the simulation model presented here, the drying can be optimized towards a more efficient use of thermal energy and a low and even moisture content in the dried biofuel.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2003. / Thesis documentation sheet inserted. Appendix reproduces four papers and manuscripts co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

The aim of this study is to investigate the possibilities of pine natural regeneration in different nature regions in the clear-cuts with main site types. The tasks of this work are: 1. to estimate a potential possibilities of pinewood natural regeneration; 2. to find out the ecological factors, that have a great influence on pine sprouts on the Na (dry not fertile), Nb (dry less than average fertile) and Lb (with excess water and less than average fertile) site types and to set their critical borders; 3. to find out the main economical factors, that promotes pine regeneration (site preparation, seed trees, shelter wood); 4. to prepare the recommendations to promote the pinewood natural regeneration. Recency and originality. This is the first investigations were made in complexly including the most common sites in Lithuania for pinewood (Na, Nb and Lb site types) in the three native regions covering largest part of Lithuania. This enables to make prognoses of pinewood regeneration in those regions on the mentioned site index. For the first time there were defined the sufficiency of the shelter-seed trees for regeneration and their distribution in a clear and step wise cutted areas to ensure the natural regeneration of pine. There were found that 2-3 point yield of pine seeds (under Capper) and on the time and in right way implemented encouragements, ensure natural pine regeneration after clear or step wise cuttings. Following the results, it was suggested to advance the... [to full text]

Darbo tikslas Nustatyti paprastosios pušies (Pinus sylvestris L.) klonų išsilaikymą ir fenologijos ypatumus lokalios amoniako taršos sąlygomis. Darbo objektas Tyrimai 2011 m. vykdyti Jonavos miškų urėdijos, Pagelažių girininkijos teritorijoje, esančiose sėklinėje plantacijoje, kuri nuo AB „Achemos yra nutolusi 6 km. Sėklinė plantacija buvo įveista 1966-1971 m. Pasodinta 30 vietinės kilmės pliusinių medžių klonų, naudota kvadratinė schema. Metodika Buvo išmatuoti visų medžių skersmenys Šiaurės-Pietų ir Vakarų-Rytų kryptimis bei įvertinta defoliacija. Apskaičiuoti visų medžių klonų vidurkiai, F kriterijus, bei paveldėjimo koeficientas. Duomenų analizei panaudota programa STATISTICA. Darbo rezultatai Tarp nagrinėjamų parametrų tarp atskirų klonų buvo esminiai genetiniai skirtumai. Paveldėjimo koeficientas − nuo 0.13 iki 0.18. Defoliacijos paveldėjimo koeficientas buvo didesnis negu skersmens. Išskirti atskiri klonai, kurių parametrai turi esminį skirtumą. Mažesnės defoliacijos klonai buvo didesnio skersmens. Darytina prielaida, kad šie klonai gerai toleruoja aplinkos taršą. Šiai hipotezei patvirtinti reikalinga klonų metinio radialinio prieaugio genetinio salygotumo tyrimas, skirtingose oro amoniako taršos koncentracijose. / Purpose The aim of the study was to determine retenton and phenology of Scots pine (Pinus sylvestris L.) clones under local ammonia pollution condition. Object Investigation was accomplised in seed plantation of Pageleziai forestry of Jonava forestry district distance 6 km from nitrogen fertilizer factory. Seed plantation was created in 1966-1971 m. There was planted 30 local genesis plus trees of Scots pine clones and exposition of field with quadratic scheme. Methods During investigation was measured all trees diametrical values of the North-South and West-East direction and the same valued defoliation. All trees were calculated means, F-test, and heritage coefficient. Describing data analysis used STATISTICA. Results Investigation between all parameters and individual clones assessed significant genetics differences. Heritage coefficient range between 0.13 and 0.18. Heritage coefficient of the defoliation were larger than diametrical values. Seperation of the individual clones parameters showed significant diferences. Clones with less defoliation were larger diameters. Assumption of this study is that these clones can tolerate environmental pollution. The hypothesis confirmed are needed annual radial increment of the clones study of the genetic conventionality under different concentration of air ammonia pollution.