A survey of primary and secondary manufacturers of eastern white pine (EWP) was executed within three regions of the Eastern US: New England, Mid-Atlantic, and Lake States. Two hundred ninety-six usable questionnaires were returned in total, with 185 coming from primary manufacturers and 111 from secondary manufacturers of EWP. The data from these surveys was used to identify differences in market characteristics between the three regions producing EWP, and also between primary and secondary industries. It was found that markets for EWP were growing in all three regions. Overall growth among primary manufacturers was estimated at 6.9% during the next 5 years, with 18.9% expected from the secondary industry. Industry members in all three regions reported that they would be able to sell more EWP products if they could get more logs. This theme of log shortage and availability was present in all three regions, and likely has to do with the loggers in those regions and how much importance they place on harvesting EWP. Results indicated that primary manufacturers overestimated how highly secondary manufacturers valued machinability, product range, and the rustic look of EWP, as significant differences were found in all of those categories. This implies that sawmills need not emphasize these aspects as much as they have been, as they are less important to customers than sawmills may have believed. Conversely, primary manufacturers underestimated how highly secondary manufacturers valued on-time delivery, consistent price, JIT delivery, and flexible payment options. These results suggest that EWP sawmills would be able to gain an advantage by putting more effort into providing these services. The effect of imported species appeared to be less than anticipated, with more than one-half of both primary and secondary respondents reporting that imports had had no impact on their operation. However, primary manufacturers were more likely to report a negative effect than their secondary counterparts, with negative response rates at 41% and 20%, respectively. / Master of Science

Understanding forest carbon uptake and associated growth response is important for carbon sequestration and water management practices given the large quantities of carbon stored in forest ecosystems. Climate variability and forest management practices influence the magnitude and rate of soil CO2 efflux; however, their combined effects are complex and not well understood. This study investigated the response of soil CO2 efflux to the combined effects of climate variability, including those caused by climate oscillations, and shelterwood harvesting in a mature temperate white pine (Pinus strobes L.) forest, located near Lake Erie in southern Ontario, Canada. Analyses indicated that local winter temperatures and precipitation were influenced by climate oscillations, which affected forest carbon dynamics. After the shelterwood harvest removed approximately a third of the overstory canopy, no significant differences were found for soil temperature and soil moisture between the pre-harvesting (2008 to 2011) and post-harvesting (2012 to 2014) periods. Despite similar climate conditions pre- and post-harvesting, soil CO2 effluxes post-harvesting were lower. A Gaussian-Gamma specification model determined that heterotrophic (autotrophic) respiration decreased (increased) between pre- and post-harvesting, respectively. Mineral-soil respiration were similar pre- and post-harvesting. Soil CO2 efflux accounted for 78±9% of the annual ecosystem respiration (RE), derived using eddy-covariance fluxes. However, the overall net ecosystem productivity showed no significant difference between pre- and post-harvesting. This was attributed to an increase in the gross ecosystem productivity post-harvesting, compensating for the increased losses (i.e. increased RE). This study highlights the complexities of measuring various components of ecosystem respiration after a disturbance, such as a harvest. The knowledge gained from this study provides a better understanding of climate variability and shelterwood harvesting influences on ecosystem respiration and can be useful for forest managers focused on carbon sequestration and forest conservation. / Dissertation / Doctor of Science (PhD) / Coniferous forest plantations in eastern North America are undergoing silvicultural management to enhance their carbon sequestration capabilities and native-tree species diversity. This study investigated the combined influence of climate oscillations and shelterwood harvesting on soil carbon dynamics of a planted pine forest in southern Ontario, Canada. Between pre- and post-harvesting, soil temperature and soil moisture did not show any significant differences. However, soil CO2 effluxes in post-harvesting years were lower than pre-harvesting years. A Gaussian-Gamma specification model determined that heterotrophic (autotrophic) respiration decreased (increased) post-harvesting and mineral-soil respiration was similar between pre- and post-harvesting. An increase in ecosystem respiration post-harvesting, despite soil CO2 efflux decreasing and being the largest component, was primarily caused by the increase in autotrophic respiration due to enhancement in forest growth. This study improved the understanding of forest carbon dynamics by highlighting the importance of accounting for all components, which may contribute to ecosystem respiration. Results can be useful for forest management practitioners, specifically those focused on carbon sequestration and forest conservation.

Ring-width chronologies from Pinus resinosa Ait., Pinus strobus L., and Thuja occidentalis L. were developed in two areas of the Boundary Waters Canoe Area Wilderness to assess their growth climate response and their potential for developing reconstructions of climate. New red pine chronologies were combined with existing chronologies to extend the ring-width record both into the past and into the present. Ring-width response to climate, assessed using correlation analysis and response functions, was broadly similar among all three species with relatively significant positive relationships with June–July precipitation and significant negative (but less consistent) associations with June–July temperatures (p < 0.05). White-cedar appeared to have a broader phenological window of response with a stronger spring influence when compared to other species included in this study. Comparisons with other nearby proxies showed relatively strong coherence overall but with some important regional differences. Overall, these species may be useful for placing current climatic patterns in the Boundary Waters within a longer term perspective but care should be taken with respect to identifying appropriate climatic records for calibration.

This dissertation thesis deals with two aspects of Eastern white pine. The first objective of this research was to evaluate the effect of the amount of solar radiation on the parameters of natural regenerated Eastern white pine individuals -- density, height, stem diameter, height increment and crown morphological parameters. The second objective of this work was to compare the production potential (stem volume, stock) of Eastern white pine and native Scots pine. For both purposes were selected forests stands with appropriate representation of Eastern white pine in Hradec Králové municipal forests. For the first objective study showed that the amount of light is a key factor in relation to Eastern white pine regeneration. Increasing amount of light significantly affects both density and growth parameters (height, stem diameter, height increment) of natural regenerated individuals. Effect of light on crown morphological parameters has not been proved. For the second objective evaluation of data showed that same old Eastern white pine in the same habitat reaches significantly greater stem volume than Scots pine in the order of several tens of percent, depending on the age of forests stand.

6 Abstract This study aimed to compare the mycorrhizal fungal communities inhabiting the roots of invasive Pinus strobus L. and native Pinus sylvestris L. We also compared carbon allocation into ectomycorrhizal fungal (EcMf) and other structures of the two pine species. The aim was to assess the influence of mycorrhiza on the invasive potential of P. strobus in the protected areas of National Park Bohemian Switzerland. The two field experiments were conducted on three locations of each species. We estimated the EcM extramatrical mycelium (EMM) production by measuring the ergosterol content in sterile sand filled mesh-bags. Next measured variables were: biomass of ectomycorrhizal and saprotrophic sporocarps, fine roots biomass and leaf litter biomass to compare the one season production of each measured variables. The results revealed a major difference in EcM sporocarps production, whereas on the P. sylvestris sites was the production 100% higher. Same results came from the fine roots measurements: P. sylvestris had a higher fine roots production, which may be also related with the production of EMM, which was about 60% higher as well. The EcMf species richness on the P. strobus root-tips was as high as the native pine, but the species composition was different. The P. strobus prefers EcMf species with...

<p>We evaluated 3-D imaging of coarse root structure and biomass using ground-penetrating radar (GPR). GPR surveys were conducted in a white pine forest in southern Ontario, Canada. GPR profiles were obtained across two test plots (6 and 17 m² area), using 1-GHz GPR and a MEMS (micro-electro-mechanical systems) accelerometer. Test plot surveys evaluated the effects of micro-topography, soil moisture content, and root diameter and spacing. In addition, with the aid of the outcome of the control test plots two other plots (25 and 400 m²area) were surveyed with varying line sample spacing to investigate the restraints on resolution brought about by line sampling density.</p> <p>Accounting for antenna tilt is necessary to determine an accurate and more precise position of root mass. The antenna tilt was >45^o pitch, >28^o roll and up to 10^o yaw due to surface micro-topography of the forest floor. Vector 3-D imaging enhanced the diffraction amplitude (15.5% increase) and centralized the position of the root. Radial surveys provided root continuity and produced better root imaging.</p> <p>GPR largely underestimates coarse root biomass when a line spacing of 25 cm is used. However similar results are found with smaller line spacing (12.5 cm). A maximum line spacing of 10 cm provided continuous root structure and differentiation of roots spaced 10 cm apart and greater. A sampling line spacing of 5 cm and an inline sampling interval of 0.5 cm in low soil moisture conditions provided the detection of roots that were a minimum of 1.4 cm in diameter.</p> / Master of Science (MSc)

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Comprendre le fonctionnement des écosystèmes est un enjeu crucial, en particulier dans un contexte de changements globaux. Afin de mieux prédire les processus écosystémiques, j’ai testé la précision et les limites des hypothèses du biomass-ratio de Grime (HBMR) et de l’annulation idiosyncratique (HAI), cette dernière étant une hypothèse originale de cette thèse. Pour cela, j’ai appliqué le principe du biomass-ratio aux traits fonctionnels, en employant la méthode des traits agrégés en communauté, pour estimer la réponse globale des espèces en mélange. La décomposition des litières plurispécifiques constitue un bon modèle biologique, pour lequel je me suis posé les questions suivantes : (1) est-ce que l’HBMR prédit bien les taux de décomposition en mélanges plurispécifiques ? ; (2) est-ce que le degré de variabilité de ces taux diminue pour des raisons biologiques avec l’augmentation de la richesse spécifique (RS) des mélanges (HAI) ? ; (3) est-ce que la variabilité des taux entre mélanges diminue quand les conditions abiotiques du site deviennent plus limitantes ? ; (4)considérant que les mélanges plus contrastés fonctionnellement sont susceptibles de développer plus d’interactions, est-ce que la déviation à la prédiction augmente avec la dispersion fonctionnelle des mélanges(« FDis », La liberté & Legendre 2010) ? Cette thèse inclut deux expériences de décomposition en sachets à litières : (1) à Sherbrooke (QC, Canada) avec des microcosmes, impliquant des litières de six espèces d’arbres, décomposant seules et en mélanges et (2) sur trois sites au climat contrasté dans la région de Clermont-Ferrand (France) avec des litières de quatre espèces d’herbacées, décomposant seules et en mélanges. Les résultats montrent des déviations positives et négatives par rapport aux taux prédits, mais l’HBMR décrit bien la réponse moyenne des litières plurispécifiques. Bien que l’HAI ait été rejetée, les résultats montrent une convergence des taux observés vers les taux prédits quand (1) la RS des mélanges augmente, (2)l’échelle spatiale augmente et (3) le climat est plus limitant pour la décomposition. Enfin, malgré des corrélations entre FDis et interactions entre espèces dans les litières, cette relation n’est pas généralisable et l’hypothèse de corrélation positive entre FDis et déviation à l’HBMR a été rejetée. / Understanding ecosystem functioning is a key goal in ecology, especially in the context of global changes. To better predict ecosystem processes, I tested the accuracy and the limits of Grime’s biomass-ratio (BMRH) hypothesis and a novel idiosyncratic annulment (IAH) hypothesis. I applied the biomass-ratio to functional traits, using the community-weighted means (CWM) to estimate the global response of species in mixtures. I studied the decomposition of litter species mixtures as a biological model and asked the following questions : (1) does the BMRH predict well the decomposition rates of mixed species litters ? ; (2) does the degree of variability of these rates decrease with increasing species richness (SR) beyond that expected from purely mathematical causes (IAH) ? ; (3) does the variability of rates between mixtures decrease with less favourable abiotic conditions for decomposition ? ; (4) as more functionally contrasted mixtures are expected to develop more interactions, does the deviation from prediction increase with increasing functional dispersion in mixtures (« FDis », Laliberté & Legendre 2010) ? This study involves two decomposition experiments using litterbags : (1) at Sherbrooke (QC, Canada), in microcosms, involving litters from six tree species, decomposed alone and in mixtures and (2) in three climatically contrasted sites in the region of Clermont-Ferrand (France) with litters from four herbaceous species, decomposed alone and in mixtures. Despite both positive and negative deviations from expectation occurring at all levels of SR, the BMRH well described the average response of mixed species litters. Although I rejected the IAH, the results showed a convergence to the predicted values based on CWM with (1) increasing the SR in mixtures, (2) increasing the spatial scale of the study and (3) a less favourable climate to decomposition. Finally, although there was a correlation between litter interactions and functional divergence, this relationship was not generalizable and I rejected the hypothesis of a positive correlation between FDis and the deviations from BMRH.

Sommaire : Comprendre le fonctionnement des écosystèmes est un enjeu crucial, en particulier dans un contexte de changements globaux. Afin de mieux prédire les processus écosystémiques, j’ai testé la précision et les limites des hypothèses du biomass-ratio de Grime (HBMR) et de l’annulation idiosyncratique (HAI), cette dernière étant une hypothèse originale de cette thèse. Pour cela, j’ai appliqué le principe du biomass-ratio aux traits fonctionnels, en employant la méthode des traits agrégés en communauté, pour estimer la réponse globale des espèces en mélange. La décomposition des litières plurispécifiques constitue un bon modèle biologique, pour lequel je me suis posé les questions suivantes : (1) est-ce que l’HBMR prédit bien les taux de décomposition en mélanges plurispécifiques ? ; (2) est-ce que le degré de variabilité de ces taux diminue pour des raisons biologiques avec l’augmentation de la richesse spécifique (RS) des mélanges (HAI) ? ; (3) est-ce que la variabilité des taux entre mélanges diminue quand les conditions abiotiques du site deviennent plus limitantes ? ; (4) considérant que les mélanges plus contrastés fonctionnellement sont susceptibles de développer plus d’interactions, est-ce que la déviation à la prédiction augmente avec la dispersion fonctionnelle des mélanges (« FDis », Laliberté & Legendre 2010) ? Cette thèse inclut deux expériences de décomposition en sachets à litières : (1) à Sherbrooke (QC, Canada) avec des microcosmes, impliquant des litières de six espèces d’arbres, décomposant seules et en mélanges et (2) sur trois sites au climat contrasté dans la région de Clermont-Ferrand (France) avec des litières de quatre espèces d’herbacées, décomposant seules et en mélanges. Les résultats montrent des déviations positives et négatives par rapport aux taux prédits, mais l’HBMR décrit bien la réponse moyenne des litières plurispécifiques. Bien que l’HAI ait été rejetée, les résultats montrent une convergence des taux observés vers les taux prédits quand (1) la RS des mélanges augmente, (2) l’échelle spatiale augmente et (3) le climat est plus limitant pour la décomposition. Enfin, malgré des corrélations entre FDis et interactions entre espèces dans les litières, cette relation n’est pas généralisable et l’hypothèse de corrélation positive entre FDis et déviation à l’HBMR a été rejetée. // Abstract : Understanding ecosystem functioning is a key goal in ecology, especially in the context of global changes. To better predict ecosystem processes, I tested the accuracy and the limits of Grime’s biomass-ratio (BMRH) hypothesis and a novel idiosyncratic annulment (IAH) hypothesis. I applied the biomass-ratio to functional traits, using the community-weighted means (CWM) to estimate the global response of species in mixtures. I studied the decomposition of litter species mixtures as a biological model and asked the following questions : (1) does the BMRH predict well the decomposition rates of mixed species litters? ; (2) does the degree of variability of these rates decrease with increasing species richness (SR) beyond that expected from purely mathematical causes (IAH)? ; (3) does the variability of rates between mixtures decrease with less favourable abiotic conditions for decomposition? ; (4) as more functionally contrasted mixtures are expected to develop more interactions, does the deviation from prediction increase with increasing functional dispersion in mixtures (« FDis », Laliberté & Legendre 2010)? This study involves two decomposition experiments using litterbags: (1) at Sherbrooke (QC, Canada), in microcosms, involving litters from six tree species, decomposed alone and in mixtures and (2) in three climatically contrasted sites in the region of Clermont-Ferrand (France) with litters from four herbaceous species, decomposed alone and in mixtures. Despite both positive and negative deviations from expectation occurring at all levels of SR, the BMRH well described the average response of mixed species litters. Although I rejected the IAH, the results showed a convergence to the predicted values based on CWM with (1) increasing the SR in mixtures, (2) increasing the spatial scale of the study and (3) a less favourable climate to decomposition. Finally, although there was a correlation between litter interactions and functional divergence, this relationship was not generalizable and I rejected the hypothesis of a positive correlation between FDis and the deviations from BMRH.