Global ETD Search

161	Conservation of boreal moth communities in the mixedwood boreal forests of northwestern Alberta: Impacts of green tree retention and slash-burning Kamunya, Esther W Unknown Date No description available. Mixedwood boreal forest Green tree retention Moths Caterpillars Forest Canopy Light traps
162	Variable Retention Harvesting: Mortality of Residual Trees and Natural Regeneration of White Spruce Solarik, Kevin Unknown Date No description available. Variable Retention Harvest Boreal Mixedwood White Spruce Natural Regeneration Tree Mortality Multivariate Regression Tree Analysis
163	Effects of Stocked Trout, Native Small-bodied Fish, and Winter Surface Aeration on Zooplankton in Small Boreal Foothills Lakes Holmes, Teslin G. Unknown Date No description available. Zooplankton Stocked Trout Native Small-bodied Fish Winter Aeration Boreal Lakes
164	Oil Sands Mine Reclamation Using Boreal Forest Surface Soil (LFH) in Northern Alberta MacKenzie, Dean D Unknown Date No description available. Mine Reclamation Boreal Forest Revegetation Propagule Stockpiling Salvage Placement Smoke Water Viability Germination Oil Sands
165	Structure, composition and trophic ecology of forest floor predatory mites (Mesostigmata) from the boreal mixedwood forest of northwestern Alberta Diaz Aguilar, Irma Unknown Date No description available. Mesostigmatan mites Mixedwood boreal forests Community composition Trophic structure Mixozercon genus
166	Sensitivity of vessels in black ash (Fraxinus nigra Marsh.) to fire and hydro-climatic variables Kames, Susanne 14 September 2009 (has links) Little research has been conducted on the sensitivity of earlywood vessel in ring-porous tree species in response to flooding. The impact of flooding and climate on vessel characteristics in black ash (Fraxinus nigra Marsh.) was studied in the boreal region of Lake Duparquet, northwestern Quebec. In addition to standard tree-ring measurements, numbers and cross-sectional area of earlywood vessels were examined and measured using an image analyzing program. Interestingly, among all Spearman rank correlations between chronologies and hydrologic/climatic variables, the strongest associations were found between earlywood vessel chronologies from floodplain trees and spring river discharge data. High water discharge in the spring was negatively correlated to earlywood vessel area and inversely correlated to number of vessels. The mean earlywood vessel area chronology developed from floodplain trees was found to be the best proxy for high magnitude flood events and it has potential to be used for flood reconstructions. dendrohydrology dendroclimatology Fraxinus nigra ring-porous vessels flooding southern boreal forest fire black ash tree-rings
167	Long-term stand dynamics of the boreal mixed-wood forests of west-central Manitoba Levac, Joshua 03 April 2012 (has links) To understand the temporal dynamics of a forest, long-term direct observations are required. My study examined the long-term persistence of trembling aspen (Populus tremuloides Michx) and white spruce (Picea glauca (Moench) Voss) in the boreal mixed-wood forests of Riding Mountain National Park. A set of 266, disturbance-free, permanent sample plots were established in 1947 (stand age = 120 years) and followed through time for 55 years. My results indicate that although the density and basal areas of aspen do decline over the 55-year period, a successful regeneration and establishment occurs around 140 years. The long-term persistence of aspen is a result of clonal reproduction following the canopy breakup beginning around 130 years or earlier. This implies that the long-term persistence of both aspen and spruce occur and the expected succession to softwood dominance does not occur. forest ecology succession long-term persistence boreal mixed-woods trembling aspen white spruce
168	Short-term effects of controlled conservation burning Rindzevičius, Vytautas January 2014 (has links) In this study, the immediate and short term (three months) effects of conservation burning have been investigated in coniferous forests in southeastern Sweden. Five tree species were investigated Picea abies (Norway spruce), Pinus sylvestris (Scots pine), Populus tremula (aspen), Betula pendula (silver birch) and Betula pubescens (downy birch), as well as ground vegetation of mosses, dwarf shrubs and ground lichens. Burning increased the proportion of live deciduous tree shoots from 51 % to 81 % and the live tree shoot size distribution of four tree species was significantly changed by fire. Fire affected the tree species differently. Three months after burning deciduous tree species exhibited strong sprouting, while P. sylvestris had established many seedlings, significantly increasing its share of the tree stand. P. abies lacked any visible positive response to burning and its number of live shoots decreased by 83 %. Mineral soil was exposed on only the moss vegetation and covered just 4 % of the studied plot area. The initial vegetation response to fire was negative, but significant dwarf shrub recovery was detected three months after burning. forest forest fire burning nature conservation conservation Sweden fenoscandia Norway spruce Scots pine aspen Picea abies Pinus sylvestris Populus tremula Betula vegetation trees tree shoots follow-up followup boreal boreal forest ekology skog skogsbrand brand bränning naturvård bevarande Sverige fenoscandia gran tall asp Picea abies Pinus sylvestris Populus tremula Betula vegitation träd trädskott trä skott upfäljning followup boreal boreal skog ekologi
169	How does nutrients and light affect algal growth in Swedish headwater streams? : A study using nutrient diffusing substrate and natural gradients of light / Hur påverkar näring och ljus algtillväxt i svenska bäckar? : En studie med diffunderande näringssubstrat och naturliga ljusgradienter Andersson, Jannika January 2014 (has links) Gaining knowledge about what factors determine benthic algal biomass and productivity is vital for understanding food webs in aquatic systems, especially in woodland streams with naturally low rates of primary productivity. The aim of this study was to investigate what factors determine algal growth in Swedish headwater streams. Nutrients, in terms of nitrogen (N) and phosphorus (P), and light are factors known to affect algal growth. By using nutrient diffusing substrate (NDS) and different gradients of light, it was possible to test the importance of these factors. To determine the effect of the experiment, the study was carried out in a forested reference stream, which is largely shaded with extreme low nutrient levels, and in a stream running through a clear-cutting plantation with high nutrient levels and incident light. In the forested reference stream it became clear that algal growth increased by experimentally adding N (P<0.005), although light did not affect the productivity. In the stream running through the clear-cut, algal productivity increased significantly with higher levels of light (P<0.005), regardless of nutrient addition. The results from this study suggest that light only becomes the depending factor when sufficient amounts of nutrients are available. However, it is still unclear at what nutrient levels this shift occur, and therefore future research is recommended. : boreal streams algal productivity N limitation nutrient diffusing substrate incident light
170	A System of Mapping Historical Wildfire Events in the Boreal Forest using Polarimetric Radar Hobart, Geordie 10 April 2015 (has links) The boreal forest covers 11% of the earth’s land surface and contains 37 percent of the planet’s terrestrial carbon, which is more than the combined total of both the tropical and the temperate forests [1]. This estimate translates to 703 Pg of carbon with the vast majority contained within the organic soils and peat layers [2-4]. The western-north American boreal forest is a fire ecosystem [2, 5-7] where fires typically occur every 50 to 200 years [8, 9], allowing vast quantities of carbon to re-enter the atmosphere. Understanding and estimating past fire history and the related changes in carbon budget [3, 4, 7, 10] in this biome is of significant importance for climate researchers as they attempt to model for future changes in the planet’s climate [2, 4, 11-14]. Many techniques are available to remotely sense wildfires - using optical, thermal and passive microwave remote sensors - during and immediately after an event - although resolution and availability of images due to cloud cover can make these techniques operationally challenging. Radar remote sensing can provide a complement to these optical and passive microwave techniques, since radar is not affected by cloud cover and solar illumination levels. The Advanced Land Observatory Satellite (ALOS) operates a phased array L band synthetic aperture radar (PALSAR) and Canada’s Radarsat-2 contains a C-Band (SAR) instrument. These radar satellites can be used to detect information about the boreal forest environment including the effects of wildfire. Polarimetric radar is an emerging technology whose full potential is still being actively explored and discovered. More specifically, this research is ground-breaking since very little work has been performed investigating the relationship between polarimetric radar data and historical boreal wildfire events. This area of investigation is a complex marriage of forestry, geospatial information and radar engineering that requires an extensive array of data sets to facilitate analysis. This research has demonstrated that both PALSAR L-Band and Canada’s Radarsat-2 C-Band full polarimetric radars can be used to detect and classify wildfire scars within individual images. The boreal forest is a dynamic ecosystem where both the level of burn severity and the subsequent regeneration of the forest is affected by many factors that can vary widely across small distances. This work contributes to the understanding of the relationships between remotely sensed quad-pol radar signals and both the boreal ecosystem and how wildfire interacts in this environment. / Graduate / 0478 / 0538 / 0984 / ghobart@nrcan.gc.ca radar boreal wildfire remote sensing PALSAR Radarsat ALOS polarimetric forest carbon

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