The impacts of current forest management methods on surface water quality, especially in northern parts of Sweden, are largely unexplored. In this review reports linked to logging impacts on catchment biogeochemistry, (with special emphasis on boreal ecosystems) has been assessed. Logging disturbances in boreal forest catchments can change biogeochemical processes in soils by alter transpiration, soil conditions, temperature, soil microbial activities and water fluxes. Combined these changes can cause increased soil nutrient leaching to receiving waters. In the studies reviewed, dissolved organic carbon (DOC) concentrations and export generally increased after logging. Similar responses followed for phosphorous (P), but to a lesser extent for nitrogen (N). Streamflow and peakflow and the export of suspended matter (SM) can also be altered after logging. Removal of streamside vegetation may result in increased stream water temperatures and potentially affect lake water temperature, deepen the epilimnion and deplete oxygen (O2) concentrations. Increased wind exposure can resuspend sediments and potentially release bioavailable P. Affected lake water concentrations of N can be considered negligible after logging, whereas tot-P concentrations has shown to increase to an almost twofold level in some studies. The overall impact on the pelagic productivity are therefore most likely those connected to increased DOC and SM concentrations. The general impact on fish biomass can be considered insignificant. In conclusions, to improve future forest management and for further understanding concerning the biogeochemical environmental impacts that forestry might have on freshwaters, additional studies are still required.

Atmosphere carries multi-faceted meaning when considered in the context of spatial design. In an architectural sense, we may speak of atmosphere as a spatial quality or in the way the built or natural environment is capable of moving us emotionally. Yet, when considered in a scientific register, atmosphere may be described as a complex of observable and measurable energies, which give air substance, behavior and force. The practice of landscape architecture entails a heightened awareness of exposure, namely the exposure to meteorological processes that in turn shape much of our perceptual and haptic experience of the ‘outside’ world. The intent of this practicum will be to draw attention to the importance of both designations of atmosphere, particularly within the discipline of landscape architecture, and set within the context of phenomenology. The context of this work begins at the scale of the circumpolar boreal forest and examines a particular biological and chemical phenomenon that occurs between the atmosphere and the boreal forest biome. The scale of focus will be drawn to a site at the southern transition zone between the boreal forest and St. Lawrence mixed forest within the Temagami region of northeast Ontario, Canada. Here, the phenomenon in question is quite palpable. / May 2017

Non-ferrous smelter emissions have prompted revegetation efforts near the border towns of Flin Flon, Manitoba and Creighton, Saskatchewan to facilitate regrowth of the surrounding boreal forest. Previously, several soil amendments were tested for plant response in soils from the smelter-impacted area and one amendment, a pyrolyzed meat and bone meal (MBM) biochar, was of particular interest because of its potential to immobilize Zn. Hydroxyapatite (HAP), with a small degree of carbonate substitution, was identified as the major component of the MBM biochar. The solubility of this Ca-mineral was pH dependent, with dissolution occurring at pH 6.3; consequently, adsorption experiments were performed at a slightly lower pH (6.1 ± 0.1). Zinc adsorption kinetics were bi-phasic and could be modeled using the Elovich equation, suggesting a diffusion limited reaction likely related to material aggregation. Adsorption also was modeled using the Langmuir equation, which indicated a moderate affinity of the biochar for Zn and an adsorption maximum of 0.650 mmol Zn g-1. Synchrotron-based Zn K-edge x-ray absorption spectroscopy (XAS) indicated an inner-sphere monodentate, tetrahedral bonding of Zn to phosphate groups in the MBM biochar. This was consistent with Zn adsorbed to a HAP standard, indicating that the same sorption mechanism was involved. The ability of MBM biochar to affect Zn speciation in soils was investigated using four soils from four locations in the smelter-impacted region around Flin Flon. A 1:10 (w/w) mixture of the MBM and soil was suspended in 200-mL deionized water (pH 6.1 ± 0.1) and equilibrated for 30 d. Whereas all the soils showed a decrease in extractable Zn following equilibration, only one exhibited a change in Zn speciation—with ca. 25% of the Zn adsorbed onto the MBM biochar. Ore-derived minerals were present in all soils and strong backscattering made identification of minor Zn species difficult. However, using microprobe-based x-ray absorption near edge structure (XANES) spectroscopy, several minor Zn species were identified; including hopeite, a ZnPO4 mineral. The presence of both hopeite and adsorbed Zn are indicative of a direct Zn-phosphate reaction. These results indicate that, under certain condition, MBM biochar can be an effective soil amendment.

This study compared the effects of fire severity and salvage logging on early successional vegetation in the mixedwood boreal forest upland of Saskatchewan. The effects of salvage logging on post-fire forest stands are poorly understood. Few studies have investigated the short-term effects of salvage logging on the regeneration of boreal plant species or the long-term impact on overall forest composition and diversity. This study examines salvage logged and wildfire leave stands across three burn severity classes (no burn, low/moderate burn, and high burn) over two time periods (1 year post-fire and 10 years post-fire). The results indicate that salvage logging has a significant impact on the early regeneration of burned mixedwood boreal plant communities with the effect still evident in forest stands ten years post-fire. Salvage logging has long-lasting residual effects on boreal forest plant community development. Salvage logging one year post-fire reduced the number, diversity, and abundance of species within each of the burn severities, creating a less abundant and simplified plant community. It was also shown that salvage logging one year post-fire tended to create more homogenous plant communities similar to those communities typical of areas of moderate burn severity, constraining the effects of burn severity and decreasing the range of the vegetation communities. These findings are less pronounced, but still evident, within salvage logged stands ten years post-fire as three regrowth cover types have developed, characterised by no disturbance, moderate disturbance either by fire or salvage logging, and severe disturbance. The convergence of plant community characteristics between burn severity classes across logging treatments suggests that the effects of salvage logging do not have long lasting effects within areas of high burn severity.

This study compared the effects of fire severity and salvage logging on early successional vegetation in the mixedwood boreal forest upland of Saskatchewan. The effects of salvage logging on post-fire forest stands are poorly understood. Few studies have investigated the short-term effects of salvage logging on the regeneration of boreal plant species or the long-term impact on overall forest composition and diversity. This study examines salvage logged and wildfire leave stands across three burn severity classes (no burn, low/moderate burn, and high burn) over two time periods (1 year post-fire and 10 years post-fire). The results indicate that salvage logging has a significant impact on the early regeneration of burned mixedwood boreal plant communities with the effect still evident in forest stands ten years post-fire. Salvage logging has long-lasting residual effects on boreal forest plant community development. Salvage logging one year post-fire reduced the number, diversity, and abundance of species within each of the burn severities, creating a less abundant and simplified plant community. It was also shown that salvage logging one year post-fire tended to create more homogenous plant communities similar to those communities typical of areas of moderate burn severity, constraining the effects of burn severity and decreasing the range of the vegetation communities. These findings are less pronounced, but still evident, within salvage logged stands ten years post-fire as three regrowth cover types have developed, characterised by no disturbance, moderate disturbance either by fire or salvage logging, and severe disturbance. The convergence of plant community characteristics between burn severity classes across logging treatments suggests that the effects of salvage logging do not have long lasting effects within areas of high burn severity.

Anthropogenic climate change is expected to dramatically affect boreal forests, not only through warming effects, but through changes in seasonal and diurnal temperature patterns, precipitation, cloud-cover, and direct effects of rising CO2. My doctoral research examines the impact of these changes on dominant boreal forest conifer species, using dendrochronological methods. Through my analysis of white spruce (Picea glauca) and lodgepole pine (Pinus contorta) tree rings across five Yukon Territory sites, I found that white spruce growth is showing growth declines in response to all three measured climate changes, with negative correlations between tree ring increment and spring and summer temperature, spring frost events, and growing season cloud cover. Lodgepole pine populations exhibited growth enhancement with increasing spring maximum daily temperatures, but generally neutral responses to warming summers, higher frost event frequency and increased cloud cover. To evaluate the effect of rising CO2 on boreal forest growth, I examined three representative managed forest stands across Canada, first building a model of climate effects, and examining temporal trends in the residual growth patterns. I found evidence for CO2 fertilization in Ontario black spruce (Picea mariana) and Manitoba white spruce populations, particularly at younger ages, but no growth enhancement in Yukon lodgepole pine. These results taken together suggest that Yukon white spruce may suffer pronounced growth declines under continued climate change, but more eastern spruce populations may be better able to benefit from increased carbon availability. Yukon lodgepole pine populations are less vulnerable to the impacts of climate change, but are also unlikely to exhibit significant growth increases in response to increasing temperature, frost events, cloud cover or rising CO2. The results from this thesis have important implications for future management of the Canadian boreal forest under progressive climate change.

Anthropogenic climate change is expected to dramatically affect boreal forests, not only through warming effects, but through changes in seasonal and diurnal temperature patterns, precipitation, cloud-cover, and direct effects of rising CO2. My doctoral research examines the impact of these changes on dominant boreal forest conifer species, using dendrochronological methods. Through my analysis of white spruce (Picea glauca) and lodgepole pine (Pinus contorta) tree rings across five Yukon Territory sites, I found that white spruce growth is showing growth declines in response to all three measured climate changes, with negative correlations between tree ring increment and spring and summer temperature, spring frost events, and growing season cloud cover. Lodgepole pine populations exhibited growth enhancement with increasing spring maximum daily temperatures, but generally neutral responses to warming summers, higher frost event frequency and increased cloud cover. To evaluate the effect of rising CO2 on boreal forest growth, I examined three representative managed forest stands across Canada, first building a model of climate effects, and examining temporal trends in the residual growth patterns. I found evidence for CO2 fertilization in Ontario black spruce (Picea mariana) and Manitoba white spruce populations, particularly at younger ages, but no growth enhancement in Yukon lodgepole pine. These results taken together suggest that Yukon white spruce may suffer pronounced growth declines under continued climate change, but more eastern spruce populations may be better able to benefit from increased carbon availability. Yukon lodgepole pine populations are less vulnerable to the impacts of climate change, but are also unlikely to exhibit significant growth increases in response to increasing temperature, frost events, cloud cover or rising CO2. The results from this thesis have important implications for future management of the Canadian boreal forest under progressive climate change.

The main aim of this study was to analyse the long-term effects on epiphytic lichen dry mass development, diversity and community structure after exposure to a simulated nitrogen deposition gradient. A whole tree experiment was set up in a boreal forest in the County of Västerbotten in Sweden, whereby 15 trees were artificially irrigated and nitrogen fertilized during seven consecutive years (2006-2012). The treatments were equal to an additional deposition of 0.6, 6, 12.5, 25 and 50 kg N ha-1 yr-1. Branches from the trees were collected in October 2012 and the lichen material was harvested and further analysed during the spring 2013. The results from this study showed that the lichens were directly affected by the long-term increased nitrogen deposition. Generally, lichen dry mass and species richness declined at high nitrogen loads and the initial positive effects of low nitrogen loads reported in a preceding study had thus depressed with time. The results from this study also showed that the composition of the lichen community changed benefitting nitrogen-tolerant species, probably not because of competition but more likely because of nitrogen-sensitive species disappearance. This study strongly indicates that it takes more than a few years to detect changes in lichen communities exposed to enhanced nitrogen loads. In addition low concentrations seem to have a cumulative impact. Consequently, this study stresses the importance of also considering the cumulative effect of low nitrogen loads when determining critical values. The critical load for lichen communities in boreal forests might be below 6 kg N ha-1 yr-1.

Leaf Area Index (LAI) is an important input variable for forest ecosystem modeling as it is a factor in predicting productivity and biomass, two key aspects of forest health. Current in situ methods of determining LAI are sometimes destructive and generally very time consuming. Other LAI derivation methods, mainly satellite-based in nature, do not provide sufficient spatial resolution or the precision required by forest managers. This thesis focused on estimating LAI from: i) height and density metrics derived from Light Detection and Ranging (LiDAR); ii) spectral vegetation indices (SVIs), in particular the Normalized Difference Vegetation Index (NDVI); and iii) a combination of these two remote sensing technologies. In situ measurements of LAI were calculated from digital hemispherical photographs (DHPs) and remotely sensed variables were derived from low density LiDAR and high resolution WorldView-2 data. Multiple Linear Regression (MLR) models were created using these variables, allowing forest-wide prediction surfaces to be created. Results from these analyses demonstrated: i) moderate explanatory power (i.e., R2 = 0.54) for LiDAR models incorporating metrics that have proven to be related to canopy structure; ii) no relationship when using SVIs; and iii) no significant improvement of LiDAR models when combining them with SVI variables. The results suggest that LiDAR models in boreal forest environments provide satisfactory estimations of LAI, even with low ranges of LAI for model calibration. On the other hand, it was anticipated that traditional SVI relationships to LAI would be present with WorldView-2 data, a result that is not easily explained. Models derived from low point density LiDAR in a mixedwood boreal environment seem to offer a reliable method of estimating LAI at a high spatial resolution for decision makers in the forestry community. / Thesis (Master, Geography) -- Queen's University, 2012-09-24 16:18:09.96

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