Thèse doctorat : Informatique : Lille 1 : 2003. / N° d'ordre (Lille 1) : 3296. Résumé en français et en anglais. Bibliogr. p. 133-136.

Thesis (M.Sc.)--Saint Mary's University, 2009. / Includes abstract. Supervisor: Kevin Kelloway. Includes bibliographical references (leaves 68-75).

Three sugarbushes were selected for the study of root distribution. Saint-Hippolyte was the best site for the distribution and production of fine roots. A high water-table and an abrupt change in texture limited the extension of the root system to the top 40 cm at the Vaudreuil site. In Tingwick, an acid mineral B horizon with a low Ca saturation restricted the production of fine roots in that horizon. / A sugarbush in Norbertville was used as a replacement for the Vaudreuil site for the study on root chemistry. The Saint-Hippolyte site had the best overall nutrient status. The molar ratio Ca/inorganic Al and Mg/inorganic Al in solution never reached values low enough to be considered toxic for the growth of fine roots. However, Al seems to increase the imbalance between Ca and K and may be responsible for the low foliar P found at Norbertville. Aluminium may also inhibit Ca uptake by roots due to very low Ca content in Tingwick.

The study of biogeochemical cycles and their role in ecosystem function has helped to highlight the impacts of human activities on natural processes. However, our understanding of the effects of nitrogen (N) deposition on forested ecosystems remains limited due to the variable controls on N cycling. Soils, microclimate, and vegetation can influence rates and processes of N cycling, singly or in concert at multiple scales. Understanding how these factors influence N cycling across the landscape will help to elucidate the impacts of N deposition. The objectives of this study were to characterize variation in soils, microclimate and vegetation characteristics, and N cycling and decomposition dynamics across the landscape in a region impacted by N deposition. Relationships among these factors were explored to determine the main factors influencing N cycling and decomposition. Strong differences in net N mineralization and nitrification were found between forest stands with contrasting species composition and moisture availability. Nitrate production and leaching were related to sugar maple abundance, and base cation leaching was correlated with nitrate concentrations in soil solutions. Decomposition experiments were installed to examine the effects of substrate quality, microclimate and N availability on decay rates. Nitrogen amendments for the most part did not affect decomposition rates of wood and cellulose, and mass loss rates were correlated with microclimate and forest floor characteristics. In contrast, microclimate did not seem to affect leaf litter decay rates, and the results suggest that the presence of invertebrates may influence mass loss to a greater degree than moisture or litter quality. This work highlights the large degree of variability in N processing across the landscape and suggests that differences in microclimate and species composition may help to predict the impacts of chronic N deposition on N cycling and retention.

Problems developing tall oak seedlings of high abundance have become a concern throughout many eastern hardwood forests. The decline in oak seedling recruitment into canopy positions is often attributed to the increasing abundance of shade tolerant midstory species, especially red maple (Acer rubrum L.). Studies have shown that increasing light to the understory by way of a midstory removal has the ability to favor oak seedlings over competitors. The majority of studies to date have examined northern red (Quercus rubra L.) and cherrybark oak (Quercus pagoda Raf.) on productive sites, but relatively little is known about the effects of midstory removal on white (Quercus alba L.) and black (Quercus velutina L.) oaks, which are valuable species commercially and for wildlife. This study tests the effect of a midstory removal on oak seedlings and red maples six years after treatment implementation. In addition to seedling growth, survival, and competitiveness, the study also illustrates the changes in canopy structure and light transmittance resulting from the midstory removal. Basal clipping response of white oak seedlings following six years under a midstory removal is also examined as a method for regenerating more vigorous oaks. Results from this study support implementation of midstory removal as a method for improving oak regeneration.

This thesis examines the extent to which sugar bush management in Eastern Ontario might contribute to biodiversity maintenance and conservation and therefore be promoted as a form of rural sustainable development. Ontario government policy seeks to actively promote actions that strengthen the province’s rural communities and protect biodiversity. Therefore sustainable development is an important concept to encourage in rural areas. The production of maple syrup on sugar bushes has already been demonstrated to be economically, socially, and in some aspects ecologically sustainable. This study seeks to determine how the operation of sugar bushes might also contribute to ecological sustainability through the maintenance and conservation of forest biodiversity. I identified three documents published by the Eastern Ontario Model Forest (EOMF): a set of management principles for conserving biodiversity on private woodlots, a list of biodiversity indicators, and a manual for monitoring them. I monitored three of the biodiversity indicators (spring ephemerals, birds, and frogs) on three of the larger sugar bushes in the Eastern Ontario and established that the EOMF biodiversity monitoring practices and guidelines were suitable for working sugar bushes. Using the management principles for biodiversity conservation developed by the EOMF, I interviewed 22 sugar bush operators in Eastern Ontario. With these interviews I addressed two objectives: 1. To generate empirical information regarding the management practices of maple sugar bush operators in Eastern Ontario and to compare these with established management principles for forest biodiversity conservation in the region 2. To generate suggestions for woodlot operators and government policymakers alike about future opportunities for research and management decision-making. The results of the study show that although most operators do not have a formal management plan for their sugar bush, many of their management practices are consistent with prescribed biodiversity conservation principles. Sugar bush operators are receptive to conserving biodiversity on their properties. The findings suggest that through sound management and planning, small-scale commercial sugar bush operations generally can be made environmentally sustainable, and become important components in broader rural development strategies. This study provides new insights into how small-scale sugar bush management, when practiced well, is consistent with conservation principles and with sustainable development principles more generally. It shows how sugar bush operators in Eastern Ontario can help the province reach its goals of biodiversity conservation and rural development set out in Ontario’s Biodiversity Strategy (2005) and Ontario’s Rural Plan (2004).

Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 38-43). Also available via Humboldt Digital Scholar.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 60-64). Also available via the Internet.

Mémoire (M.Ress.Renouv.)-- Université du Québec à Chicoutimi, 1992. / Résumé disponible sur Internet. CaQCU Bibliogr.: f. 73-76. Document électronique également accessible en format PDF. CaQCU

University, Diss., 2006--Kassel.