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

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A field experiment tested the effectiveness of carbaryl and two pyrethroid insecticides, cyfluthrin and esfenvalerate, in protecting high-value Engelmann spruce trees from attack by Dendroctonus rufipennis Kirby. Carbaryl suspension at the 2% registered rate and a reduced rate of 1 % were both effective in protecting Engelmann spruce from attack by D. rufipennis through two pheromone baiting periods and 24 months following insecticide application . Cyfluthrin at 0.025% rate and esfenvalerate at 0.025 and 0.05% rates provided effective protection through one pheromone baiting and 12 months following insecticide application. Only cyfluthrin at 0.008% rate was judged ineffective protection 12 months following insecticide application. A laboratory evaluation utilizing a 32-h bioassay on D. rufipennis adults determined all three insecticides were toxic by contact. Carbaryl and piperonyl butoxide bioassays testing synergism were inconclusive. The methodology presented provides a means for forest land managers to quantify insecticide toxicity and monitor for resistance development.

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Spruce-fir ecosystems of the eastern United States interest scientists because of reported changes in population growth. Whether red spruce (Picea rubens Sarg.) populations are declining because of disease, pollution or environmental stress or experiencing natural changes in stand development is unclear. This research examined the growth and physiological responses of red spruce seedlings to changes in atmospheric CO₂ water and nutrient availability to determine the response of this species to potential climatic changes. Red spruce seedlings were grown from seed for 1 year in ambient (374 ppm) or elevated (713 ppm) CO₂ in combination with low or high soil fertility treatment, and well-watered or water-stressed conditions. Red spruce seedlings grown with limited nutrient and water availability increased growth in elevated CO₂ as did seedlings grown with high soil fertility treatment and ample water. At 12 months of age, elevated CO₂-grown seedlings had greater dry weight, height, diameter and specific leaf weight than ambient CO₂-grown seedlings. Seedlings that formed a bud in elevated CO₂ at 5 months of age produced more total fixed growth than seedlings grown in ambient CO₂. Mean relative growth rate was greater in elevated than ambient CO₂-grown seedlings only from 3 to 5 months of age. Growth was greater at 12 months despite a lower photosynthetic rate in elevated CO₂-grown seedlings compared to ambient CO,-grown seedlings. Transplanting seedlings from 175-cm³ pots into 646-cm³ pots at 7 months did not change growth and physiological responses to elevated CO₂ at 12 months. Dry weight allocation patterns to leaf, stem and root were not influenced by growth in elevated CO₂ for 1 year. Drought-conditioning had a greater influence on the physiological responses of red spruce to decreasing water potential than did growth in elevated CO₂. Results from this research suggest that red spruce seedlings will grow bigger faster in a future elevated CO₂ atmosphere even if water and nutrients are limiting. / Ph. D.

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The Spruce Point Site (DjKq-1) in the northwestern sector of Lake of the Woods, Ontario, is a Selkirk site dated through ceramic seriational analysis to the sixteenth or seventeenth century A.D. It is rare for two reasons. First, it is a single component among a plethora of multi-component sites with collapsed stratigraphy which characterize the major portion of the Lake of the Woods prehistoric record. This factor allows for the first analysis and description of Lake of the Woods Selkirk community patterns, material remains, especially ceramics, and adaptive strategy free from stratigraphic interference. The assemblage is represented by ceramics and lithics akin to the Winnipeg River Complex and a faunal sample indicating an exploitation pattern using an unspecialized strategy and varied resources. Second, the site has remains of two house structures, unreported elsewhere for the Selkirk Composite, that are similar in floor plan and size to earlier Laurel structures and later Cree houses reported in the ethnographic literature. House style and geographic location, plus the faunal assemblage indicate the site was occupied during the summer and was chosen for its varied animal, plant and lithic resources.