Thesis (M.S.) in Forestry--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 67-72).

Thesis (Ph. D.)--Oregon State University, 1986. / Typescript (photocopy). Includes bibliographical references (leaves 126-131). Also available via the World Wide Web.

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Root development in Picea glauca seedlings was studied anatomically during the first year after germination. The cyclic pattern of elongation of individual roots was established about three months after germination. With progressing development, root hairs gradually diminished and colonization of roots by mycorrhizal fungi increased. The development of primary tissues in long roots, relative to the distance from the root tip, appeared to be related to their rate of root elongation. In these roots, the development of Casparian bands in the endodermis often occurred several millimeters away from the root tip. In elongating short roots, endodermal cells attained their primary state only 2-4 cells away from the proximal part of the apical meristem. In non-elongating roots, the secondary-state endodermis was connected to the metacutis just above the apical meristem. The development of Casparian bands was always prior to the maturation of the first xylem elements. The endodermis did not develop past the secondary state. Through the presence of passage cells, it remained functional until its disruption by secondary growth. Low frequency of plasmodesmata in the endodermis indicated that the plasma membrane - cell wall - plasma membrane type of transport was the main means of molecule exchange between the cortex and the stele in white spruce roots. Undifferentiated tissues of the root near the apical meristem were almost impermeable to fluorescent dye tracers Sulforhodamine G and fluorescein diacetate. The metacutis and the endodermis at the primary and secondary state were impermeable to the apoplastic tracer Sulforhodamine G. Roots and root systems were structurally and physiologically affected by cultural treatments such as pruning and fertilizer application. Roots of seedlings grown at low nitrogen (N) supply were thin and their tracheids were narrow. Excess N did not significantly increase root diameter and tracheid dimensions, compared to the optimum supply. Dimensions of bordered pits were not significantly affected by the N level. The secondary development in roots advanced basipetally but exceptions were found indicating that cambial growth of roots could vary along the root regardless of the position relative to the root tip. Seedlings with different root systems modified by nursery culture exhibited different pattems of root growth after planting. Root elongation and root surface area increases immediately after planting were greater in container-grown than in mechanically box-pruned seedlings but this was unrelated to the longer-term performance of these seedlings. The initially low hydraulic conductance of root systems in box-pruned seedlings increased significantly 6-8 weeks after planting while it remained unchanged or declined in container-grown seedlings. Root pressure, comparable to that reported for angiosperm seedlings, was found in white spruce seedlings during the first few weeks after planting. This is contrary to the general notion that conifers do not develop notable root pressure. The initiation and elongation of roots in unfertilized organic compartments was poor compared to root growth in unfertilized mineral compartments, especially in mechanically pruned seedlings whose roots proliferated in the latter compartments. The growth of roots in the organic substrates was enhanced by the addition of slow-release fertilizer to that substrate. The growth response of roots to slow-release fertilizer added to the mineral substrate was restricted to that compartment but root growth in both soil compartments was affected by the addition of slow-release fertilizer to the organic substrate. Root development in different types of planting stock was differently affected by the soil substrate type and the addition of the slow release fertilizer. / Graduate

Investigations were carried out to determine the effect of ecological factors on the induction of diapause in the spruce budworm. Experimental rearings were conducted at elevations of 2500, 4200 and 4750 feet. The foliage of spruce, Douglas fir and alpine fir were used as hosts. Progeny of Ontario, two-year and one-year types reared under one-year and two-year life cycle conditions were used as experimental insects. A trend was observed in emergence from hibernation with the one-year type leading, followed by the two-year and finally the Ontario type. It was shown that the one-year type larvae may adopt the two-year habit. The main factor influencing this is a prolonged development period for the parents. The larvae reared at the higher elevations showed a greater proportion entering diapause. Food played a smaller role with spruce and Douglas fir being more favourable for diapause than alpine fir. The increased percentage of larvae in diapause in 1952 is attributed to a longer development period for their parents and to a sharp drop in temperature occurring about 12 days prior to diapause. The Ontario material may adopt the two-year habit. The factors contributing to this have not been clearly shown as the rearing results are inconclusive. There were no definite differences shown in the time for development among the three foods. The insects at the lowest station developed in approximately three weeks less time than at the highest. The difference between the upper stations was slight. The impracticability of converting a one-year life cycle population to a two-year cycle by forest management is noted. The diapause theories of Wigglesworth and Andrewartha are commented on. A possible course of evolution leading to the establishment of a two-year life cycle population is given. / Science, Faculty of / Zoology, Department of / Graduate

In the region of Lillooet, B.C. a small population of spruce budworm, Ohoristoneura fumiferana (Clem.), has maintained a relatively constant sub-epidemic level for several decades, feeding on Douglas fir, Pseudotsuga taxifolia (Poir.) Britt. No tree mortality has occurred. This population has been under observation for ten years, and it is apparent that an effective natural control complex is operating in the area. Spiders are prominent among the predators of insects in the region. Field observations revealed that many spiders captured both larvae and moths of the spruce budworm. A collection of arboreal spiders of the region was made and identified. Feeding tests were conducted with spiders to determine the budworm-feeding species. Both caged and free spiders were tested. Population samples were taken to determine the relative abundance of spider species in the area, and to discover any differences that may exist between spider populations in the infested forest and in the non-infested forest. Four families were found to comprise eighty percent of the arboreal spiders of the Lillooet district, and seventy percent consisted of only two families, the Thomisidae and the Salticidae. The Thomisids do not capture spruce budworm larvae, but may capture moths. The Salticids capture both larvae and moths. Families Argiopidae and Theridiidae occasionally capture larvae and frequently capture moths. No difference was demonstrated between spider populations in the infested forest and the non-infested forest. / Forestry, Faculty of / Graduate

An environmental study using the association concept and the 'ecological groups' within the biogeoclimatic zonal framework was conducted in the Sub-Boreal spruce zone in British Colimbia [sic]. Quantitative information on the vegetation and environment of the zone has, hitherto, been lacking. Seventy seven stands have been studied. From the six upland associations, delimited by the methods of Zurich-Montpellier School using Domin-Krajina scale, soils from seventeen different Soil Great Groups have been distinguished and described. The relation between vegetation and soil morphology are obvious at the zonal and association levels but are less distinct at lower levels. Based on fourteen sample plots, four low moor associations on nine Mesisols, four Fibrisols and one Humisol are also described. Microclimatic data, air and soil temperatures, humidity, precipitation and snow cover have been recorded from five stands that differed in canopy density, ground cover, species composition, in soil conditions and topography. Air and soil temperature patterns show a remarkable similarity. Diurnal temperature fluctuations are most pronounced under Pinetum contortae while such fluctuations are much less under Alnetum tenuifoliae and Piceetum glaucae. Chemical analyses of 280 soil samples include a wide range of both macro- and micronutrients as well as some toxic heavy metals. Analyses involved water soluble and replaceable major cations, total nitrogen and available phosphorus, and water soluble, replaceable, EDTA- and HCl-extractable trace metals. The soils under white spruce-devil's club and river alder-ostrich fern are the richest in both macro- and micronutrients, followed by aspen and black spruce. Seemingly soils of the black spruce sites sampled show a high nutrient content but it looks doubtful if all these are readily available because of impeded drainage and low base saturation. From the study of the sites, nutritional requirements of subalpine fir appear to be high and those of lodgepole pine very low. Neither the chemical characteristics of the low moor organic soils nor the water chemistry seem to show any distinct relationship with the vegetation of these sites. Using multiple regression analyses eight statistically significant environmental gradients have been used in the study. The soil texture gradient is based on the weighted averages of the sum of percentage silt and clay content calculated for the rooting depth. The water gradient has been established on the available water capacity expressed as a percentage of the rooting volume of the soil. Five nutrient gradients have been established. The calcium and magnesium gradients are based on the replaceable content expressed as equivalents per square meter of the soil rooting volume. Nitrogen gradient based on total nitrogen analysis are expressed as grams per square meter of the rooting volume. Gradients based on EDTA-extractable manganese and iron are expressed the same way as nitrogen. The light gradient is based on observations from fiftyeight plots, extended over a period of two years, using a chemical light meter. All gradients are quantified and the correlations of associations along these gradients are shown. Of all the gradients considered in the study, plant communities showed better correlations with soil texture, water and replaceable calcium. Using relative species significance rather than presence, distributional patterns of individual species along these gradients have been illustrated. Predictive equations based on regression analyses using both transformed measured values and their logarithms have been given for a number of plant species. / Science, Faculty of / Botany, Department of / Graduate

Forest insects and diseases active in immature interior spruce stands in the central interior of British Columbia and their possible implications in forest management practices have been surveyed. Collection records, spanning the period 1949 to 1982, from the Forest Insect and Disease Survey of the Canadian Forestry Service were reviewed for the Prince George Timber Supply Area and the pest incidence in immature interior spruce stands summarized. Twenty-two plantations, established between 1963 and 1973, were surveyed to determine the relative incidence of the major insect and pathogen pests of immature spruce in Supply Block 'G' of the Prince George Timber Supply Area. A bud midge, likely Rhabdophaga swainei Felt (Diptera: Cecidomyiidae), and a terminal weevil, Pissodes strobi Peck (Coleoptera: Curculionidae), were found to consistently infest and damage a significant number of immature interior spruce trees. A spruce stand stocking profile was developed as a basis for discussion of management practices in plantations and immature stands. The stocking profile can be used in the determination of not only pest management policy decisions but in stand management decisions affecting stand density and, ultimately, merchantable yield at harvest. The findings confirmed that forest management must be actively practiced throughout the life of a forest stand. To be successful, however, stand management guidelines and merchantable yield projections are required. These guidelines and projections must include the influences of insects and diseases upon the forest crop in their development model. This information is particularly important in the development of complete Timber Supply Area plans and for the flagging of pest hazard periods during the development of spruce forests. / Forestry, Faculty of / Graduate

A study was carried out to investigate the effects of slashburning on the nutrient status of two Sub-Boreal Spruce zone ecosystems in the west central interior of British Columbia. The slash, forest floor and mineral soil (0-15 cm depth) in these ecosystems were sampled for mass and nutrient content before and after burning on a recently clearcut site. The forest floor and mineral soil were also sampled for nutrient concentrations nine months following burning. Average losses of organic matter, N, P, S, K, Ca, and Mg to the atmosphere due to slashburning were 11.1 kg/m² and 563, 55, 87, 60, 252, and 16 kg/ha, respectively, from the mesic ecosystems and 11.5 kg/m² and 345, 52, 74, 16, 289, and 177 kg/ha, respectively, from the subhygric/hygric ecosystems. These amounts corresponded to 51, 47, 41, 56, 40, 40 and 20%, respectively, of the total quantities of these nutrients in the slash and forest floor in the mesic ecosystems before burning, and 25, 9, 13, 14, 5, 6 and 17%, respectively, of the cjuantities in the subhygric/hygric ecosystems. There were substantial losses of organic matter from coarse (>8 cm diam.) and fine ≤ 1 cm diam.) slash and the forest floor components. However, nutrient losses were largely attributed to fine slash and forest floor consumption. Nutrient losses from the fine slash appeared to be independent of fire severity, although losses of most nutrients from the forest floor increased with fire severity; in plots in the mesic ecosystems which received moderate impact burns, and plots in the subhygric/hygric ecosystems which received low and moderate impact burns, net gains in forest floor Mg, K, and K and Ca content, respectively, were found. Nine months following burning there were significant increases in pH and total Mg concentrations and decreases in exchangeable K concentrations in the forest floor in the mesic ecosystems and S concentration in the forest floor in plots which had received low impact burns in both ecosystems. Effects of burning on some nutrient concentrations were confounded by the inherent seasonal variability in labile nutrient forms. There were no significant changes in mineral soil nutrient concentrations that could be attributed to burning. However, any such changes of small magnitude would have been difficult to detect due to the high spatial variation in soil nutrient concentrations. The survival and growth of interior spruce seedlings in the first season following outplanting was better in burned than in unburned areas in both ecosystems. However, seedling foliar N and P concentrations were lower in the burned areas. It is concluded that if slashburning is carried out in the mesic ecosystems, low to moderate severity fires should be prescribed to preserve the nutrient capital present in the forest floor. Slashburning would not substantially reduce the nutrient capital of subhygric/hygric ecosystems even with much higher fire severities than were observed in this study. / Forestry, Faculty of / Graduate