Norway spruce (Picea abies L. Karst.) is an important conifer tree species widely distributed in Europe. Genetically, the population of this large range is divided in two differentiated groups: a southern and a northern European group. In the northern European group, the fossils records tell us that after the last glaciation this species recolonized from one main refugium located around the Moscow region, in Russia.             In this study, the genetic diversity and structure of 101 populations of Norway spruce collected all over the northern European range were examined using an indel polymorphism in mitochondrial DNA (mtDNA). The polymorphism was used to investigate the migration routes of this species after the last glaciation.                        The distribution of the detected two haplotypes (A and B) was geographically well structured as haplotype A was restricted to Scandinavia, while haplotype B was found all over the examined range. The value of averaged intrapopulation gene diversity (HS=0.09) was lower than total populations gene diversity (HT=0.28) and a relatively high value of genetic differentiation among populations was detected (GST=0.68). The genetic structure detected in this study suggested that a second refugium for spruce might have been present in Scandinavia. This study would shed light on our understanding of the postglacial migration history of Norway spruce.

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Diss.--Freiburg i.B. / Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 112-119).

Thesis (M.S.) in Ecology and Environmental Science--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 69-73).

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Successful establishment of boreal tree seedlings like trembling aspen (Populus tremuloides Michx) and white spruce (Picea glauca (Moench) Voss.) in reclaimed oil sands mining sites is often limited by low nutrient availability and competition from the ground cover vegetation like planted cover crops and weeds. Competing vegetation can adversely affect seedling establishment by augmenting the impacts of moisture and nutrient stress. Despite high potential of barley (Hordeum vulgare L.) and oats (Avena sativa) as cover crops in oil sands reclamation, it was not well known how these crops interact with fertilization to influence early survival and growth of tree seedlings. This study evaluated the potential of fertilization and other silvicultural practices to improve revegetation success in oil sands sites reclaimed with peat-mineral mixture. Fertilizer application significantly increased height and root collar diameter (RCD) of tree seedlings in controlled environment greenhouse conditions, but not at a field research site near Fort McMurray, Alberta. In a greenhouse study, alleviating soil moisture stress significantly increased height, RCD, and biomass of tree seedlings. Vigorous growth of ground cover vegetation stimulated by fertilizer addition in both the greenhouse and field, largely controlled survival and growth responses of tree seedlings. Survival rates of tree seedlings were significantly decreased with increased fertilizer application rates, and no positive growth responses were observed in the field. Maximum seedlings survival (92%) was recorded without fertilization. Trembling aspen was sensitive to ground cover competition, whereas white spruce was unaffected. The inherent fertility of the peat-mineral mixture appeared sufficient for establishment and early growth of planted tree seedlings in recently reclaimed oil sands sites. Fertilization appeared to increase competition between tree seedlings and cover vegetation by promoting increased growth and competition for other resources like water. Effects on growth over the longer term (several years) should be evaluated in future studies.

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In microcosms, <i>Picea sitchensis</i> seedlings were grown aseptically in perlite + vermiculite with NH<SUB>4</SUB>-N or NH<SUB>4</SUB>NO<SUB>3</SUB>-N, with an ectomycorrhizal fungus, <i>Lactarius rufus</i> and/or a saprotrophic fungus <i>Hygrophoropsis aurantiaca</i>. Total and fluorescein diacetate (FDA) active hyphal length, mycorrhizal infection and plant dry weight were measured (8 to 16 weeks). In perlite with NH<SUB>4</SUB>-N, total hyphal length of extramatrical mycelium (EMM) produced by <i>L. rufus</i> was 693 m gdwt perlite or 47 m per mycorrhizal root-tip. This was reduced to 141 m gdwt in the presence of <i>H. aurantiaca</i>. Nutrient solution pH and plant growth were also reduced. In liquid culture, acidification of the medium (H<SUP>+ </SUP> equivalent) per NH<SUB>4</SUB> ion uptake was ≤ 3.8 times greater for <i>H. aurantiaca</i> than <i>L. rufus</i>. Growth (dwt) of <i>H. aurantiaca</i> was inversely related to pH. Growth of <i>L. rufus</i> was unaffected by pH 2.7 to 5.0. In perlite + vermiculite with NH_4-N, <i>L. rufus</i> hyphal length was unaffected by the presence of <i>H. aurantiaca</i>. In this experiment, no mycorrhizas formed in treatments with NH_4NO_3-N and EMM production by <i>L. rufus</i> was greatly reduced compared to treatments with NH_4-N. In a different experiment with NH_4NO_3-N, total hyphal length of EMM for <i>L. rufus</i> grown alone was apparently greatly reduced, (compared with an experiment with NH_4-N) but was increased in the presence of <i>H. aurantiaca</i>. Plant dry weight was also increased in the presence of <i>H. aurantiaca</i> with perlite + vermiculite. Total hyphal length of <i>H. aurantiaca</i> was not affected by the presence of <i>L. rufus</i> in any experiment. FDA-active hyphal length of both fungi decreased or remained constant and was 1% to 3% of total hyphal length at a week 16. Percentage mycorrhizal root-tips was similar between treatments at week 16 but differences occurred at weeks 8, 10 and 12 which suggested an inverse relationship between % infection and pH.