In this study, pollen contamination (measured by the number of seeds pollinated by pollen not belonging to any of the clones on the seed orchard) is compared between open pollination and isolated pollination environments in a Scots pine (Pinus sylvestris) seed orchard called Västerhus, located outside Önsköldsvik. In this seed orchard a tent experiment is taking place. Skogforsk has built six large tents covering 12-14 trees with each tent. Fertilization patterns were compared between one tree in a tent with a supplementation of pollen from five clones not represented in the tent and another tree of the same clone subject to open pollination outside the tents. By using DNA markers the paternity was determined for 48 seeds from each tree. The results show a big difference in pollen contamination between the two trees. The tree inside the tent showed a contamination rate of 0% and the tree from the open pollination had a contamination rate of 20,5%. No difference was found in the numbers of different fathers although the selfing rate of 4,26% was higher in the tent than the selfing rate of 2,56% observed in the open pollination environment. These results match the results of other studies done on the same orchard pretty well and therefore tent isolation with a supplementary pollination can be a good way to reduce unwanted pollen contamination.

Diplodia tip blight is an important disease of pines, especially Scots pine Christmas trees in Kentucky. The hypothesis for my thesis work was that D. pinea could be acquired and transmitted on the tools during annual shearing of the Christmas trees. Samples taken from tools after shearing on two different Christmas tree farms in Kentucky in 2005 and 2006 yielded D. pinea colony forming units, but in very low quantities; typically less than 10 CFUs per collection. Diplodia-associated dieback from the sheared tips was never found in the field, suggesting that transmission and subsequent infections were not occurring via these sheared tips. Controlled infections indicated that a minimum of 100 spores was necessary to create symptomatic infections on sheared tips. Lysolandamp;reg; Disinfectant Spray did not remove D. pinea from tools when sprayed on them after shearing, but it did effectively prevent spore germination in vitro. Observations of Diplodia lesion development on one Scots pine Christmas tree farm in Kentucky during the springs of 2006 and 2007 suggested that D. pinea infections occurred primarily via the bases of needle bundles on elongating shoots. The most likely source of inoculum was dead infested pine tissues within and beneath the canopy. The use of a protectant fungicide may have resulted in an observed dramatic decrease of disease on this farm.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2008. / Härtill 5 uppsatser.

Drought-induced tree mortality is a phenomenon affecting many forest ecosystems and is predicted to increase under ongoing climate change. Forest stability partly depends on regeneration: the process of renewing mature forest with subsequent generations. As seedlings are more susceptible to drought effects than mature trees, mortality of the seedling bank can represent a major bottleneck controlling forest structure and species composition. Scots Pine (Pinus sylvestris L.) is the most widely distributed of the Pinus species, covering a broad latitudinal gradient of ecological conditions. The thesis aims to deepen understanding of drought-induced mortality, while analysing intra-specific variation in the phenotypic and metabolic profile of Pinus sylvestris seedlings subjected to drought stress. I also consider the relevance of the results to the broader conceptual framework of drought-induced mortality. The experiments utilise seeds from different populations of origin (provenances) across the north-south axis of the European range of Pinus sylvestris, in order to determine the extent of regeneration capacity in this species under drought. Seeds were collected from different populations (provenances) that, along with other climatic and edaphic differences, span a gradient of water availability: from wet (Scotland) to intermediate (Austria, Poland) to dry (Spain). In Chapter 2, the effects of osmotic stress on the initial seedling establishment stage were studied by comparing phenotypic responses across provenances. Seedling germination, early growth, osmotic stress tolerance and survival were investigated using a polyethylene glycol irrigation treatment as a proxy for rapid and severe drought. Treatment, provenance and interaction effects were found for rate of germination, final proportion of seeds germinated, seedling size, and superoxide dismutase activity (an antioxidant enzyme). Root investment was affected by both provenance and time to germination. Although there was no significant effect of provenance on survival, a trend towards increased probability of survival under osmotic stress was indicated for the southernmost (driest) as compared with the northernmost (wettest) provenance. Chapter 3 investigates the responses of older seedlings (at 10 months) to a drying down of soil moisture for 40 days. Morphological and physiological data were collected to assess intra-specific and intra-population variation in the seedling stress response under drought. A metabolomics analysis using Ultra performance Liquid chromatography followed by mass spectrometry (UPLC/MS) was carried out to investigate whether metabolic markers could be identified that are suggestive of heightened oxidative stress and whether populations in different climatic and edaphic environments show variation in metabolic activity under drought. Preliminary results suggest large intra-population variability yet clear differentiation in metabolic responses to drought over the time course of the experiment. Univariate and multivariate analyses indicated that among the most significant increases in response to drought were those involved in osmoprotective and antioxidant capabilities, including the free amino acid proline and a quercetin derivative (a flavonoid). Interestingly, provenances, either under experimental drought or not, did not show significantly different metabolite profiles, even though provenance and its interaction with drought treatment did significantly affect seedling biomass and photochemical efficiency. In Chapter 4 the effects of provenance, maternal parentage and seed weight on germination rate, final germination percentage, as well as seedling drought responses in biomass allocation and the expression of selected antioxidant genes were analysed. Seed weights were measured individually and seed weight was found to have a strong positive effect on: germination rate, seedling dry weights, and number of needles. Expression of two antioxidant enzymes increased under drought. Seed weight was strongly determined by provenance and maternal parentage as well as their interaction. However, root to shoot biomass allocation depended on provenance and maternal effects that were not mediated by seed weight effects. Principal component analysis indicated that the Spanish provenances could be characterised by a higher root to shoot ratio and stem weight. Specific leaf area was also found to be lowest for the Spanish provenances.

Scots pine (Pinus sylvestris L.) form a large part of Swedish forestry and has many alternative end-use areas with different requirements for quality. The ability to influence the quality is high in the initial planting and juvenile forest phase, as studies have shown relationships between good quality and dense planting, where competition between trees has a good impact on timber quality. Competition can also be achieved by shading from above, through seed trees or multi-layered forest. Interest in continuous cover forestry grows, and investigating differences in future timber quality between layered and clear cutting treatments can therefore be valuable. Such a method is “Naturkultur”, which aims to optimize the net present value at every point in the forest. The purpose of this study is to highlight the question of whether layered forests methods similar to “Naturkultur” can be used for higher timber quality in pine forests in a cleaning trial in southern Östergötland, Sweden. The goal is to find out if any difference in timber quality exists in the future butt log between the different cleaning treatments, layered (Uneven) and conventional (Even). The survey was limited to studying only the Kråkerödjan pre-commercial thinning trial, located on the property Kråkerödjan between Småland and Östergötland. Parameters for quality estimation were delimited to knot quantity and knot thickness. In order to answer the purpose, a field survey was conducted with quantitative assumptions where data about stem quantity, tree species distribution, height, diameter, height of the living crown, number of knots and diameter for the thickest knot from the base of the trunk up to 2 m on the trunk were collected. The result showed that the number of stems per ha was significantly higher in Uneven than in Even while the volume was next to the same. The average diameter was about 4 cm in Uneven and about 10 cm in Even. The tree species distribution was the same for trees with a diameter > 5 cm a breast height (bh) in both parcels,> 95% pine. For trees <5 cm bh, the distribution in Uneven was 14 % pine, 10 % spruce and 76 % deciduous, in Even there were almost exclusively deciduous trees. When examining pine > 5 cm at bh, there was a significant difference in the knot quantity with fewer knots/m in Uneven than in Even. The thickest knot was smaller in Uneven than in Even, but the difference was only significant when the data without dominants was examined. The thickest knot was slightly smaller relative to the diameter of the trunk in bh in Uneven but the difference was not significant. The average diameter in pine > 5 cm at bh was slightly less in Uneven, 10.7 cm, than in Even, 10.8 cm. The survey gives an indication that the layered forest according to the method of “Naturkultur” in the parcel Uneven, where dominants shades smaller trees, may be used for a better timber quality in pine in the investigated premises. However, the results are not sufficiently clear, if this is due to the fact that the quality difference is small or if it is because quality differences have not yet occurred V cannot be read in the survey. Estimating timber quality early in the rotation period is difficult as a lot can happen until final felling. However, the survey has been valuable as more data is needed in the area in question. Follow-up of the survey is needed to further explore the relationships between stock treatments and quality development.

Abstract The genetic basis of large adaptive differences in timing of bud set and frost hardiness between natural populations of Scots pine (Pinus sylvestris L.) was studied with the aid of RAPD markers and quantitative genetic tools. Steep clinal variation was found for both traits among Finnish Scots pine populations, and the differences between populations were found to be largely genetic. QTL mapping with Bayesian analysis revealed four potential QTLs for timing of bud set, and seven for frost hardiness. The QTLs were mostly different between the two traits. The potential QTLs included loci with large effects, and additionally smaller QTLs. The largest QTLs for bud set date accounted for about a fourth of the mean difference between populations. Thus, natural selection during adaptation has resulted in fixation of genes of large effect. This result is in conflict with the classical infinitesimal model, but agrees with the results of Orr (1998), suggesting fixation of large effects during adaptation. The applicability of RAPD and SSCP markers in quantitative genetic studies was also studied. The SSCP technique was found to be efficient in finding polymorphic markers. SSCP polymorphism in coding genes may provide candidate genes for QTL mapping studies. RAPDs were found to be useful for many descriptive analyses, but specific analyses would require more caution.

No description available.

Abstract Three different studies were conducted to elucidate the effects of copper (Cu) and nickel (Ni) on Scots pine needles. One was the Monchegorsk smelter emission gradient study on the Kola Peninsula, Russia, the second was the 3-year seedling and 6-year adult tree low-level CuNi and acid rain (H2SO4 at pH 3) irrigation study at Kevo, Finland. In the third study seedlings were exposed to Cu and Ni for a one season in Oulu, Finland. Ni accumulated efficiently in needles, and this accumulation was seen in each of the different studies. The Cu concentrations remained low in needles, except near the Monchegorsk smelters. The addition of Ni together with Cu in Oulu seemed to enhance the accumulation of Ni into the needles of Scots pine seedlings. Plasmolysis may be related to both drought and the Ni treatment, as observed in Oulu, because plasmolysis was statistically more abundant in the 15 mg Ni kg-1 dry soil treated needles than in other treatments except in 25 mg Ni kg-1 dry soil. Cu induced lipid peroxidation of chloroplast membranes was visible under transmission electron microscope (TEM) as light colored, swollen thylakoids in chloroplasts near the Monchegorsk smeltersand also in needles exposed to 25 Ni+50 Cu mg kg-1 in soil in Oulu. Some year to year variation in the frost hardening process was seen in metal and acid treated needles, which may have caused the maximum frost hardiness level drop after CuNi, pH3 and CuNi/pH3 treatments. Root growth was increased by 5 mg Ni kg-1 dry soil in soil in Oulu, but 15 mg Ni kg-1 dry soil Ni in soil decreased root growth and increased root tip dieback. 25 Ni+50 Cu mg kg-1 dry soil in soil markedly decreased root growth. The proportion of oxidized glutathione in Cu-treated needles was smaller than in Ni-treated needles, but roots had higher peroxidase activity levels. However, Ni seemed to cause more oxidative stress to seedlings than copper.

Scots pine (Pinus sylvestris L.) is a long-term economically preferred woody species not only from the standpoint of its wood production but also thanks to its tolerance to extreme climatic factors, environmental modesty, and resistance to drought stress. In recent years, however, due to the action of the changing climatic conditions, this economically significant woody species withers. Its increment in the natural ecotype is affected by the adaptability to the increasing intensity of temperature extremes (prolonged heat waves). The combination of the lack of precipitation and extremely high air temperatures (even in the spring season) will significantly affect the resistance of this woody species to drought stress. This thesis is focused on the analysis of the secondary xylem and phloem cells formation of Scots pine depending on the physiological and morphological changes due to the affecting drought stress. Within the scope of the forming radial cells in individual growing seasons (2013–2016), it has been evaluated how the synergy of the specific factors affecting the overall anatomic structure of the annual ring and the vitality of the examined woody species was expressed in the formation, differentiation, and overall structure of the cells. During the four growing seasons (2013–2016), micro-cores (diameter 1.8 mm) were taken in weekly intervals in the research area in Sobesice of xylem and phloem (including the cambial zone) using the Trephor increment borer. From these micro-cores, permanent microscopic slides of the cross-section were made, on which the analysis of the cambial activity, cell formation, cell differentiation with time, and the evaluation of the morphometric parameters of the formed of xylem and phloem cells were performed. It was found that in each monitored growing season, the drought stress has shown, which was reflected by the dropped of the soil water potential (below -1 MPa) and the intensity of transpiration, which led to the stress reaction of the cambium. The reaction of the drought-stressed cambial zone has been expressed by the decreased activity (a sudden drop of the number of dividing cells) and subsequently, during the recurrence of precipitation, by the reactivation when an increase of the number of dividing cells was observed again. This factor initiated the formation of the intra-annual density fluctuations (IADF), i.e. the formation of the so-called false annual ring. The sensitive reaction of the cambium to the drought stress affected the cell production time, the number of formed cells, and also the time of differentiation of individual tracheids, which was expressed by the reduction of the radial dimensions and cell wall thickness of the tracheids. The artificially induced stress by stem girdling intensified the concurrent drought factor and in the area below the girdling, the cambial activity has stopped within two weeks after the performed treatment. The formed cells were not fully differentiated, so the zone of typically thick-walled cells of latewood was missing in the annual ring. The following growing season, the radial increment was only formed in the area above the girdling (without the latewood zone) and in the second half of the growing season, the trees gradually died. The activity of the plant hormone IAA was also affected by the drought in the summer season, when its concentration dropped below the measurability threshold (2 µg sample-1). At the time of the IAA concentration drop, latewood tracheids began to form and the phloem cell formation was completed. The synthesis and activity of the soluble low-molecular carbohydrates correlated with the course of the cambial activity and the cell differentiation phases, where the dynamics of the concentration also matched the timing of the formation of the individual cell formation phases. With phloem cells, a significant variability in the morphological dimensions has not been observed compared to xylem cells. The phenology of the needles indicated the cell wall formation phases and the initiation of the latewood tracheids. Due to the fact that the needles were fully formed in the season of the spring tracheids formation, their phenology did not reflect the drought stress which was recorded mainly in the summer season. Also, the increment of phloem was formed in the spring season. It has been presented for a long time that coniferous woody species react to the drought stress by thicker cell walls formation of the latewood tracheids. However, it has been observed within the scope of the research of this thesis that the water deficit affected the cambial activity, which has expressed itself on the intensity of the cell formation and the time of their differentiation. Due to this process, tracheids with smaller radial dimensions and a narrower cell wall were formed. This gradually causes structural changes of the formed annual ring, where the typically earlywood and latewood tracheids (classified according to radial dimensions and thicknesses of cell walls) may form independently on the growth seasonality. Especially in cases of IADF formation or in combination with the case where latewood is not even formed, a problem with the validity of the classification according to the so-called Mork’s criterion begins to occur. The understanding of the effect of the specific metabolic and physiological changes on xylem and phloem formation of Scots pine helps to clarify the issues of forestation and overall wood production of this economically significant woody species.