Volatile constituents of bark from the two species of pine hosts of the mountain pine beetle, (Dendroctonus ponderosae Hopkins) were investigated as postulated factors in host tree discovery and selective attack by the insect. The anemo-olfactory, klinokinetic and klinotactic responses of pedestrian adult flown females to odors of different aged pines of the species Pinus ponderosa Laws, (ponderosa pine) and Pinus monticola Dougl. (western white pine) were used as criteria to test for evidence as to possible involvement of host tree volatiles in host selection. Volatile substances from pine bark were collected through sublimation under vacuum from frozen state. The volatile extracts were analyzed by Gas-Liquid Chromatography. Total volatile extracts and their ether soluble fraction from mature pine trees were "attractive" to beetles, whereas those from saplings were "repellent." No qualitative differences were found in the ether-soluble fraction of mature trees and saplings respectively, but proportions of individual constituents in the extracts differed. Ethanol at various concentrations caused arrestance of the anemo-olfactory response of pedestrian beetles. As a constituent of trees under stress ethanol may thus play an important role in the programme of responses which lead ultimately to attack. Problems encountered during the storage of tree samples and their extracts have been discussed. / Forestry, Faculty of / Graduate

Failure of pitched-tapered glulam beams in tension perpendicular to grain has been attributed to the inadequacy of the present method of calculating stresses. In this thesis, the factors of time and size for tension perpendicular to grain were investigated to determine how they would affect the allowable stresses. A total of 229 Douglas Fir glulam blocks of two sizes were loaded for ?0 days in uniform tension perpendicular to grain to investigate time effect. Test data were analyzed by developing estimates for the strength ratios. Results indicate that strength reductions increase at an increasing rate with the logarithm of time. The presently used time factors were shown to be conservative and could be increased for the 2-month, the 7-day and the 1-day durations. Experimental data also indicate that the present time factors may be non-conservative for load durations less than 5 minutes and more than ?0 days. In addition, short-term testing of 24-0 Southern Pine glulam blocks of three sizes was performed to investigate size effect. Results show that the relationship between specimen strength and volume is a straight line in a log.-log. plot, thus verifying the weakest-link model for Southern Pine. Comparison with Douglas Fir data taken from literature was also made. It was found that Southern Pine is definitely stronger than Douglas Fir In tension perpendicular to grain. Size effect, however, is almost identical for the two species. Significant difference was observed in the long-term test results between the two specimen volumes. This may be due to the effect of size, but it could also be caused by the different stress levels used for the two volumes. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The needle chlorenchyma of Pinus contorta Dougl. ex Loud spp. Lat? - folia (Engelm. ex Wats) was fixed on site in the sub-alpine forests of the southern interior plateau of British Columbia, in order to conduct comparative observations by light and electron microscopy on the chloren-chymal cytology in summer and winter. Material fixed in the growing season (summer) demonstrated a chlorenchymal ultrastructure similar to that of other mature higher plant chlorenchymal tissues. Material fixed in mid winter (usually at below freezing tempertures) revealed extensive changes in the structural and positional aspects of most cytoplasmic components. Some of the most dramatic changes in the chlorenchyma cytoplasm in the winter state are as follows: chloroplasts became irregularly shaped and clumped together usually in certain specific areas of the cell; close associations form between the outer membranes of adjacent chloroplasts, these areas may lead to the apparent fusion of some chloroplasts. The cytoplasm became massively vacuolated, particularly in areas removed from the nucleus or the chloroplast clumps. The extent of this vacuolation can be deduced from the use of the adjective "foamy" to describe the extent and degree of these vacuolated cytoplasmic areas. Associated with the cytoplasmic winter vacuoles were highly osmiophilic bodies. A distinct seasonal cycle of cytoplasmic oil reserves was also noted. The reaction of the winter chlorenchymal cytoplasm to extentive manipulation in fixative osmotic potential was remarkably conservative. This observation allows inferences to be made about the permeability characteristics of winter cytoplasmic membranes. In order to verify the observed winter changes, chemical fixation studies were supplemented by observations on material collected, transported, stored, sectioned and observed by light microscopy in the frozen and unthawed, stained or fixed state. This work was conducted with specially designed transport devices and a cryomicrotome and cryomicros-cope. Observations were also conducted in summer and winter on the chlorenchyma of Pinus albicaulis Engelm and Tsuga mertensiana (Bong.) Corr. collected near timberline at the Whistler mountain ski resort ninety miles north of Vancouver. Observations from the cryomicroscopy of Pinus contorta needles indicate that the seasonal changes are not artifacts of chemical fixation procedures. Observations on the needles of the two conifer species collected at Whistler mountain indicate that the detailed seasonal observations on Pinus contorta may also apply to the needle chlorenchyma of other conifer species. A possible spring transitional stage between the winter and summer ultrastructural appearance of Pinus contorta chlorenchyma is discussed. Related experiments were conducted to indicate what effects the needle age of field trees had on winter-summer comparisons, and what effect drought stress and artificial hardening and freezing had on chlorenchymal ultrastructure. The drought and hardening-freezing experiments were conducted on laboratory grown trees in controlled environment chambers. No clear relationship between frost hardiness and drought stress was established. Experiments on the artificial inducement of frost hardiness in seedling trees were not considered successful. / Science, Faculty of / Botany, Department of / Graduate

With reference to anatomical studies it appears that the aerpents are indeed a neglected group ot reptiles. Although some early writers recorded a few fragmentary obser-vations on the anatomy of snakes, no attempt was made to undertake a complete comprehensive study. Cole (1944) has rightfully referred to this section of vertebrate anatomy as "almost virgin field." The serpent area of reptilian anatomy is deserving ot a more intensive investigation because of the considerable number ot adaptations demonatrated by this group of reptiles in relation to their peculiar types ot locomotion and methods ot feeding. It is important to understand the anatomical specializations of this group of animals if we are to understand more completely the evolutionary trends among the vertebrates. It is also quite evident that compara-tive descriptions of certain serpents, which have been based mainly on external characteristics, need to be supplemented by accounts of their internal anatomy.

To improve the success of vegetative propagation of Sciadopitys verticillata, stem cuttings were subjected to three treatments designed to minimize the accumulation of a latex-like sap at the cut ends of stems. A 24-hour soak in water before a hormone dip significantly enhanced rooting success and root mass. The water soak pretreatment was more beneficial to hardwood cuttings compared with softwood cuttings. Cuttings from shade-grown source trees showed the highest rooting success, but source tree age, height, and place of origin were not important factors. The water-insoluble latex-like sap had strong antibacterial activity against 3 of 11 bacterial species tested, but activity was not related to bacterial Gram reaction or the bacterial natural environment. In contrast, pine resins and latexes from selected angiosperms showed no antibacterial activity. The antibacterial component of the Sciadopitys latex-like sap was heat stable and therefore probably not protein based.

Global biodiversity is in decline as a result of unprecedented human alterations to the earth’s land cover. Understanding the ecological mechanisms of these large-scale changes in biodiversity is imperative in furthering our knowledge on the effects these alterations may have on animal behaviour and consequently on populations, allowing researchers and managers to effectively conserve species. During the last decade, there have been reports of moose populations both increasing and decreasing in North America due to a variety of factors (e.g., climate change, habitat disturbance, disease, etc.). Within British Columbia, wildlife managers have reported moose population declines of up to 50 – 70%, while other areas have remained stable. These changes have coincided, spatially and temporally, with the largest recorded mountain pine beetle (Dendroctonus ponderosae) outbreak. The outbreak resulted in extensive logging and road building in attempts to recover economic value from the beetle killed trees, resulting in drastic changes to the landscape. Understanding the effects that a highly disturbed landscape has on a species is critical for effective management and conservation. To investigate this, I examined the seasonal response of female moose to landscape change caused by the Mountain Pine Beetle outbreak and attendant salvage logging infrastructure in the Interior of British Columbia on the Bonaparte Plateau. First, I used a cluster analysis framework to develop biologically relevant seasons for female moose using individual movement and habitat use. I then used this temporal framework to develop seasonal home ranges for each individual moose. Second, I modeled the seasonal habitat selection of female moose to examine how moose respond to salvage logging infrastructure (i.e., dense road network and extensive cutblocks) using resource selection functions in an information-theoretic framework. We tested whether predation risk, forage availability or the cumulative effects of salvage logging best predicted moose space-use. Moose movement data clustered into five biologically relevant seasons, which were consistent with our biological and ecological knowledge of moose in the study area; however, these seasons and the size of the range differed from other seasons defined using alternative methods in the region. Across all seasons, the cumulative effects of forage availability and risk best predicted female moose distribution. In the calving and fall seasons, the top risk model best predicted moose habitat selection while the top forage availability model better explained moose habitat selection in spring, summer, and winter. Our results identified the importance of defining biological seasons using empirical data and how these seasons can differ from arbitrarily defined seasons, as well as the implications these can have in subsequent analysis and management. Additionally, we found that moose are seasonally trading the benefits of foraging for predation risk in these highly disturbed landscapes, using some aspects of salvage logging. My results bring perspective on how moose are using a highly disturbed landscape at the seasonal scale and a nuanced approach to landscape management. / Graduate

Regeneration of forest stands is often complicated by the establishment and competition of brush on logged and burned-over areas. The encroachment of brush in the ponderosa pine type of Idaho, particularly Ceanothus velutinus, Dougl. presents a difficult problem to the forest manager. The brush competition severely reduces the growth rate of associated trees, thus extending the period necessary to grow a crop of trees. This situation may seriously limit the economic production of a wood crop of ponderosa pine. Any approach to the solution of brush problems should include a thorough understanding of brush ecology. Those phases of ecology dealing with reproduction and distribution of brush need special emphasis. It has been assumed that most of the brush on logged or burned-over areas originated from seed stored in the forest floor; yet little is known of the quantity or distribution of these seeds. This study was carried out to learn what kind, number and variability of seed is present in the forest floor, and to investigate the number of seed located in different forest conditions, aspects and soil layers. To achieve the above objectives, 48 square-foot, duff-soil samples were taken in the ponderosa pine type of the Boise Basin Experimental Forest in Idaho. Seeds were separated from the samples and major species identified, pretreated and germinated. Appropriate statistical techniques were employed to determine significant results among the different forest conditions, aspects and soil layers sampled.

Dwarf mistletoes are Parasitic flowering plants that infect conifer tree species. The effects of Arceuthobium americanum on the seed crop of Pinus contorta were examined over a two year period to evaluate the effects of altered host reproductive success on host population dynamics. Heavily infected trees produced significantly fewer cones than uninfected trees during the first season in which cones were collected. Cone length, number of seeds per cone, individual seed mass, and total calories per seed were significantly reduced in moderately and heavily infected trees. Trees with different levels of infection showed trends consistent with the above but no significant differences were observed during the second season. The number of seeds that were produced, disseminated, and that germinated per square meter of forest floor was significantly less in heavily infected plots than in lightly infected plots. Survival of one year old seedlings, however, was significantly higher in heavily infected plots. Significant increases in the abundance of woody litter due to increases in mortality of mature trees and witches brooms were positively correlated with increases in seedling survival in heavily infected plots. Survival of trees less than 45 years of age also increased as the level of infection in plots increased. This increases the fraction of total density that saplings represent in heavily infected stands. The total basal area of plots with different levels of infection were uniform, implying that all available environmental resources are being utilized. The differences in age distribution between lightly and heavily infected plots, however, indicate that resources are partitioned differently between saplings and mature trees in plots with different levels of infection. Dominant host trees experienced higher mortality in heavily infected plots than in lightly infected plots. This reduces the total biomass of all mature trees. Increased mortality of dominant host trees frees resources which reduces intraspecific competition thereby contributing to increased sapling survival in heavily infected plots. Consequently, stand density increases as the level of infection increases.

Belowground competition presents a threat to the production and sustainability of tree-grass ecosystems. Management scenarios designed to optimize the spatial and temporal distribution of soil resources will improve resource-use efficiency and promote greater co-production. We conducted three experiments to assess competition dynamics between loblolly pine and switchgrass. In a three-year field trial, loblolly pine and switchgrass were intercropped across varying competitive intensities. Interspecific competition decreased loblolly pine annual growth; however, establishing vegetation exclusion zones surrounding pines largely mitigated these effects. Switchgrass yields were less affected by interspecific competition compared to pines and land equivalency ratios indicated that with proper management co-production yields may exceed those of switchgrass monoculture. Switchgrass was a constant and significant competitor across all years while loblolly pine resource use was minimal in year 1 but increased in subsequent years. In a short-term greenhouse experiment, native soil was amended with biochar and inorganic N fertilizer and the effects of these amendments upon soil properties and switchgrass productivity were assessed. Biochar increased soil pH, total soil carbon, and soil moisture. However, N fertilization had negligible effects upon soil properties. Plant response to biochar was neutral to negative while N fertilization increased switchgrass foliar biomass but no interactive effects of the amendments were observed. Although the effects of biochar upon switchgrass production were trivial, its positive influence upon soil properties suggests a potential for mitigating competitive interactions. Finally, a field-scale study examined co-production of loblolly pine and switchgrass over two years in response to competition control, biochar, and N fertilizer. As expected, interspecific competition reduced soil resources and decreased plant productivity. Biochar increased total soil C and soil moisture levels but had relatively minor impacts upon other aspects of soil fertility or plant production. Nitrogen fertilization acidified soil pH and decreased total soil C and N but positively affected loblolly pine foliar N concentrations and switchgrass yields. A positive association between soil inorganic N and switchgrass yield suggests the species competitive influence may be increased with greater N supply.

I studied four areas in south Mississippi from 2009-2010 to examine habitat conditions and faunal communities associated with presence of black pine snakes (Pituophis melanoleucus lodingi), a candidate for federal listing. Field studies included vegetation sampling, small vertebrates trapping, and fire ant (Solenopsis invicta) mound densities estimation. Areas that supported black pine snakes exhibited vegetation communities that differed from areas that did not support pine snakes. Presence of black pine snakes was influenced by ground cover vegetation and stump hole densities. Greatest densities of ant mounds were detected in areas that supported pine snakes and gopher tortoises (Gopherus polyphemus). Species associates of black pine snakes included coachwhips (Coluber flagellum flagellum), scarlet snakes (Cemophora coccinea), six lined race runners (Aspidoscelis sexlineata sexlineata), and gopher tortoises. Findings of my study are being used to address creation of habitat corridors for black pine snakes and species associates within the Mississippi longleaf pine belt.