Thesis (doctoral)--Sveriges Lantbruksuniversitet, Umeå, 1981. / English summary. Includes bibliographical references (p. 210-220).

Thesis (doctoral)--Oulun Yliopisto, 2002. / Includes bibliographical references. Also available in electronic format.

No description available.

<i>Brunchorstia pinea</i> (Karst.) Hohn [perfect = <i>Ascocalyx abietina</i> (Lagerb.) Morelet] causes shoot dieback in conifers. Damage of Scots pine plantations in Britain was first reported in the late 1970s, previously only Corsican pine was damaged. In both these species initial shoot tissue symptoms of water soaked and necrotic development in the buds and internodes were shown to develop earlier in the winter than they did in Europe and N.America. The milder winter conditons in Britain were thought to be invovled. Internode infections were relatively more frequent compared with bud infections in Scots pine than in Corsican pine. This leads to proportionally more shoot deaths due to internode girdling in Scots pine than in Corsican pine. In both species bud scales, proximal portions of the leaf scales and internode epidermis were proposed as sites of infection. Corsican pine was more susceptible to infection by <i>B.pinea</i> than Scots pine but not to development of necrosis in the tissue. Norway spruce was successfully infected which gives the first record of <i>B.pinea</i> on Norway spruce in Britain. Pyncidial production was greater on diseased Scots pines than Corsican pines and was believed to influence potential epidemic development. Variation in susceptibility within a Scots pine stand was associated with β-phellandrene levels of the cortical monoterpene component. High altitude favoured <i>B.pinea</i> as shoot vigour was low. It was proposed that prolonged periods of high humidity favoured <i>B.pinea</i> survival in shoot tissues as well as dissemination and germination of spores. Winter shading did not influence <i>B.pinea</i> development. Recent attacks of <i>B.pinea</i> in Britain were not due to increased pathogen virulence. Apothecia which are rare in Britain, were found in association with unusual environment conditions. Recent outbreaks of <i>B.pinea</i> were thought to be due to environmental conditions reducing host vigour and favouring <i>B.pinea</i> development.

Thesis (doctoral)--University of Oulu, 1987. / Accompanied by reprints of 4 articles by the author and others on same topic. Includes bibliographical references (p. [34]-39).

Call number: LD2668 .T4 1986 A42 / Master of Science

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2003. / Thesis documentation sheet inserted. Appendix includes reproductions of four papers and manuscripts, three co-authored with others. Includes bibliographical references. Abstract also available online.

No description available.

The study examined the damage caused to naturally regenerated Scots Hue by red deer and certain other mammals and birds, and its effect on the development of natural woodland. Investigations were concentrated in three areas, which carried high, moderate and low stockings of red deer, in the upper Dee valley in Aberdeenshire. Most marked trees, above 2-3 inches in height, suffered some degree of browsing during the study period. Simulated browsing experiments, supported by data from study plots, showed that survival and growth of trees decreased with increased browsing severity. Severe browsing had less serious effects on large trees than on small ones. In response to browsing, new shoots were produced from large overwintering buds in larch and birch but, in pine, shoots were normally produced from dormant buds, which required a growing season in which to develop before vigorous growth was possible. Where browsing pressure was high, the deciduous species generally survived longer than pine because they were not subjected to severe winter damage and they probably suffered less interruption to their photosynthetic activity as a result of their more rapid response to browsing. Tree browsing records and observations in study plots confirmed that numerous mammals and birds browsed pine. Most species, however, had relatively little effect on woodland development. Densities of rabbits and mice were very low, and pine material was probably only a minor constituent in the diet of mountain hares and red grouse. Browsing by jred and roe deer could not be distinguished consistently, but the satisfactory development of natural regeneration in exclosures, where red deer were largely excluded but roe were common, suggests that roe densities of up to approximately 1*24 acres are too low to exert a serious effect on woodland development. Sheep commonly browsed pine in winter, but most animals were nonnally taken off the hill from November to May. Browsing on young regeneration by capercaillie was apparently restricted to pine of .4-30 inches high, which were few where capercaillie were numerous. Disbudding by black grouse was widespread but, in these areas, their browsing never affected tree survival and rarely prevented the addition of some increment during the year of damage. Browsing by red deer had the most serious effects on the survival and development of pine. Browsing had relatively little effect on tree development where red deer densities were approximately 1*150 acres in winter (Cambus O'May); but it caused mortalities in trees below 30 inches high and reduced growth in trees below 60 inches, in areas where winter densities approximated to 1:60 acres (Bush Lawsie). Densities of It10 acres (Meall Alvie) totally prevented the development of woodland. A comparison of tree browsing incidence with indices of red deer abundance in study plots, and a detailed examination of the conditions under which these trees were browsed, showed that whilst intensity of pine browsing is related to deer density, the two are not directly proportional to each other. The relationship is modified by environmental factors of climate and the habitat, notably the choice and availability of tree material and of the alternative vegetation which comprises the deer*a diet. Observations on feeding, rumen content analyses and comparisons of browsing intensity on trees of different origin and appearance showed that red deer browsed certain species of vegetation, and trees of certain sizes and condition, selectively. Habitats which contained large quantities of preferred vegetation and low quantities of acceptable tree material, therefore, suffered less pine browsing proportional to their use by deer than habitats in which these conditions were reversed. Deer abundance was invariably a significant factor in the amount of tree browsing which a habitat sustained, however, because increased browsing intensity removed more preferred vegetation and acceptable tree material and forced the deer to browse more heavily on less acceptable trees. Tree mortality from trampling had little effect on woodland development because damage was confined to very small trees in areas where regeneration was profuse. Relatively few trees were affected by antler damage, but these injuries could be locally significant where tree densities are low. On grouse moors, regular heather burning was principally responsible for the absence of natural woodland. Tree mortality from insects and fungi was negligible. Deaths from climatic agencies, notably drought and frost lift, were fairly few and were largely confined to very small trees. Snowbreak might have locally serious effects on the development of larger trees in winters of exceptional snowfall.

No description available.