Variation in feeding behaviour was studied among young individuals of pumpkinseed (Lepomis gibbosus) and yellow perch (Perca flavescens). Three types of food, Drosophila, Daphnia and Artemia were used for the experiments. Eight individuals of pumpkinseed differed significantly in their number of feeding attempts, in time interval between feeding attempts (in the beginning, middle and towards the end of the experiment), feeding angle, number of unsuccessful attempts and regurgitations. Most of the differences in the time interval between feeding attempts were observed in the middle and towards the end of the experiment. When the experimental diet was composed of three types of foods (Drosophila, Daphnia and Artemia) in a mixture, the total number of feeding attempts in the experiment decreased. Mixing the food types also reduced the feeding efficiency of individuals which was evidenced by the increased time interval between the feeding attempts and the increased unsuccessful attempts and regurgitations. Individuals of pumpkinseed showed the highest preference for Daphnia. On the basis of the above feeding variables, groups of individuals of differing feeding patterns were identified. Similar patterns were observed for the eight individuals of yellow perch. Perch fed more efficiently on Artemia, however, two individuals of perch were more efficient on feeding on Daphnia. Effects of the presence of conspecifics and increasing population density were examined on the variation among individuals of the pumpkinseed and yellow perch, for two types of food, (Daphnia and Artemia), separately and in a mixture. The effects of conspecifics were not equal on each individual of pumpkinseed and yellow perch. Only the weaker individuals were affected more by the presence of other conspecifics than the stronger ones. The increasing population density of conspecifics increased the variation among the individuals of both species. The effect of the presence of heterospecifics (yellow perch) were also examined on individuals of pumpkinseed for similar food types and feeding variables. At low experimental densities the effects of the heterospecifics were not significant. However, at high densities yellow perch affected the feeding behaviour of pumpkinseed individuals significantly. The effects of conspecifics on pumpkinseed were always greater than heterospecifics. Yellow perch did not affect the feeding behaviour of all the individuals of pumpkinseed equally.

In this thesis, the environmental values of Canada and Sweden as they are embodied in the forest policy of these two countries are examined within the framework of Beck's theory of the risk society to discover whether there is evidence to support Beck's theory of the evolution of industrialised countries from primary to reflexive modernisation. The historical, cultural and social-structural conditions underlying the development of Canadian and Swedish forest policy are also investigated in order to situate those policies in their historical and comparative context.

This study provides detailed descriptions of 149 stands of the least disturbed, most mature forest communities in the Ottawa, Ontario region. For each of these sampled communities, a complete summary is provided of tree population structure, coverage and constancy of all vascular understory species and habitat data including topographic position, drainage class, and soil characteristics. Six widespread and five locally-distributed forest alliances, comprising 21 forest associations, are defined and described on the basis of presently-dominant tree species. A dichotomous key to the associations is provided. The successional trends exhibited by the present associations are integrated into a flowchart based on tree population structures, tree ages and habitat characteristics. A discussion of succession and climax theory, terminology, variability within and between associations, environmental controls and disturbance factors is provided with emphasis on comparisons with previous investigations in eastern North America.

Abstract not available.

Remote sensing offers an economical tool to perform forest mapping and to meet forest manager needs. The main objective of this thesis is to compare the results of both supervised classification and linear spectral analysis methods of forest cover mapping from the same sector of Anticosti Island. Supervised classification is a binary method of mapping where the pixel can be associated with only one thematic class whereas linear spectral mixture analysis is based on the principle of continuity, meaning that a single pixel can belong to more that one information class. To meet our objectives, the image used in this thesis was acquired on August 24 2001 by Landsat-7's ETM+ sensor. Radiometric calibration, atmospheric corrections and geometric corrections were applied to the image. Spectroradiometric data acquired by ASD (Analytical Spectral Devices) between 350 nm and 2500 nm were also used. The results show that the supervised classification performed with parallelepiped algorithm combined with the maximum likelihood algorithm produced good results for forest mapping in a mixed environment. The results from this method can be used to perform multitemporal studies regarding forest cover observation on Anticosti Island i.e., disease infestation, forest fire, heavy browsing by deer and regeneration. However, the linear spectral mixture analysis method results were not as conclusive as expected because of the limited number of spectral bands that can be used, the spectral regions covered by those spectral bands, and the similarity between the spectral signature of the different forest species.

A short history of the electronic data processing development in North America is given. The basic principles of computers and data processing systems are analysed and a brief description of ALWAC III-E and IBM 1620 computers is provided. Sufficient information is given to acquaint professional foresters or research workers in forestry with the basic knowledge required to understand where and how computing can be applied in their work. The major factors that govern how and when to use a computer are: required speed and accuracy, size, repetitiveness, and complexity of the calculation. It is pointed out that the advantages of an electronic computer are: speed, accuracy, versatility, reliability and memory. The disadvantages are: high rental cost, extra cost for transposing data on cards or tape, and complicated program writing. In forestry the main fields of electronic computer applications are: Management Mensuration Utilization Logging engineering Research Examples are presented for each field in the text, typical programs are appended, and sources of further information are noted. It is concluded that in the future the importance of electronic computers will increase in forestry practices; however, it will remain only a tool and cannot replace the forester. / Forestry, Faculty of / Graduate

[No abstract submitted] / Arts, Faculty of / Vancouver School of Economics / Graduate

Logging has proceeded continuously since 1915 in the Nimpkish valley. The cutting has been of the old-growth Douglas fir (Pseudotsuga taxifolia (Poir.) Britt, western red cedar (Thuja plicata Donn.), western hemlock (Tsuga heterophylla (RAF.) Sarg.) and balsam fir (Abies amabilis (Bougl.) Forbes. Many of the areas cut have become restocked naturally with various species of trees which are classified as second-growth. The excess of low-value trees and the slow rate of regeneration are not economically satisfactory. Since 1924 various plantations have been established. A study of the results of this natural regeneration and this artificial regeneration indicates practical methods for future procedure. Additional information comes from experiments that have been completed, and from those that are still in progress. The synthesis of the collected material and the silvicultural discourse form the basis for recommendations for future management of forestry operations in the Nimpkish valley. / Forestry, Faculty of / Graduate

The application of silvicultural systems in the B-19 Foothills, region of Alberta was examined in the light of current problems in management, silviculture, and utilisation. Following a regional description, in which a classification of site is developed, certain silvicultural systems were examined and recommended for the dominant stand types which occur on three major site groups, viz:- 1. Dry Upland 2. Moist Transition 3. Wet Consideration was given in each case to clearcutting, shelterwood and selection systems. Recommendations were based on the information presented in the preceding chapters and that available in those references cited in the bibliography. It has been pointed out in conclusion that there are three main phases in the development of control of the silviculture and management of the region. These are:- 1. The preparation of management plans for sustained yield. 2. The selection of silvicultural systems to, bring silvicultural control into the framework of sustained yield management. 3. The development and application of cultural treatments through research to improve local conditions and to help solve particular regeneration problems. The importance of the hypothesis presented in Chapter III is finally re-stressed with reference to the above mentioned development phases. That is - That there are already available to the practising forest management planner, silvicultural systems which are applicable, with or without further adaptation, to the forest stands of the region and to the sites described. Certain fields of research have been suggested throughout the text and these were summarised in a final recommendation. / Forestry, Faculty of / Graduate

An inventory of the most important indigenous and exotic Salix clones for basket making was carried out in Hungary. Eleven clones were selected from those presently growing in various parts of the country. The vegetative and generative characteristics of the shoots were described. Interspecific hybridization was carried out using five different combinations. The germination of Salix seed was studied by taking a series of photographs. Vegetative propagation by means of shoot cuttings and by "T" bud grafting were tried. A selection method was used for evaluating the different clones within the country. Five experimental plantations were set out on the more important soil regions and the eleven clones were planted in randomized blocks, each 10 by 10 meters in size. Each clone was replicated four times and 170 cuttings of each were planted in a block. The height growth of the 5th and the 10th ramets in each row were measured bi-weekly during the growing season in 1955 and in 1956. More than 100,000 height measurements were recorded. The influence of the clone, year, and locality on the average height attained was evaluated by means of an analysis of variance, and an attempt was made by using the components of variance to estimate the heritability. The simple correlation coefficients were calculated to approximate the degree of association of the average tree height, weight and volume of different clones in the five localities during the years 1955-1959 inclusive. Form of sprouts, cellulose content of one-year-old shoots, and meteorological conditions were studied. Experiments were undertaken concerning spacing and fertilization as part of the basket-willow improvement work. / Forestry, Faculty of / Graduate