Enjeux et solutions pour la sylviculture intensive de plantations dans un contexte d'aménagement écosystémique

Les plantations forestières représentent un outil sylvicole reconnu pour assurer un approvisionnement en matière ligneuse qui répond aux attentes de la société envers l'aménagement durable des forêts. Toutefois, elles font aussi partie du scénario sylvicole qui a le plus grand potentiel d'artificialisation de la forêt naturelle. Les objectifs de la sylviculture intensive de plantations peuvent alors paraître, de prime abord, en contradiction avec ceux de l'aménagement écosystémique. Nous décrivons le processus par lequel nous avons défini et documenté des enjeux associés aux plantations et proposé des pistes de solutions pour que la sylviculture intensive de plantations puisse s'intégrer à l'aménagement écosystémique. Nous avons identifié des enjeux relatifs à l'ampleur, à la localisation et à l'agencement spatial des plantations, aux attributs clés et à la résilience de la forêt naturelle, à l'acceptabilité sociale, ainsi qu’à la productivité et à la rentabilité des plantations. Nous avons également proposé des pistes de solutions qui permettraient de réaliser les plantations dans un contexte d'aménagement écosystémique, telles que la modulation des traitements sylvicoles pour augmenter la naturalité des plantations, la réalisation des traitements de manière à obtenir la production attendue, ainsi qu'un déploiement dans le paysage qui intègre les préoccupations des parties prenantes et qui considère la naturalité de la matrice forestière. Forest plantations are recognized as a silvicultural tool for ensuring a timber supply that meets public expectations regarding sustainable forest management. However, they are also part of the silvicultural scenario that shows the greatest potential for the artificialization of natural forests. From a firsthand perspective, intensive plantation silviculture objectives may appear antagonistic to those of ecosystem management. Here we describe the process through which we defined and documented plantation issues, then propose potential solutions to allow the integration of intensive plantation silviculture into ecosystem management. We identify issues related to the scale, localization and spatial arrangement of plantations, the key attributes and resilience of natural forests, social acceptability, and the productivity and profitability of plantations. We also propose potential solutions likely to help manage plantations within a context of ecosystem management. These include modulating silvicultural treatments to enhance the naturalness of plantations, conducting treatments to obtain expected production rates, and ensuring that plantations are deployed across the landscape in a manner that integrates stakeholder concerns and considers the naturalness of the forest matrix

A hemispherical retarding field energy analyzer to characterize spatially and angularly extended electron beams

International audienceWe have designed and built a hemispherical retarding field energy analyzer in order to facilitate characterization of large area electron emitters (typically field emitter arrays with active areas up to 1 cm2) with large angular aperture. A complete numerical model of the analyzer has been built, including perturbations due to secondary particles, in order to determine the analyzer performances. The analyzer energy resolution is better than 100 meV for an energy range up to 120 eV. The analyzer has a global field of view of 112° and allows measurements of the energy distribution of the beam as a function of the emission angle, as well as measurements of the beam intensity profile along any section of the beam. We have successfully used the analyzer to characterize the electron beam emitted by 1 cm2 Mo microtips-based field emitter arrays

Examination of Physicians' Perception of the Indications of Colorectal Stents in the Management of Malignant Large Bowel Obstruction: A Provincial Survey

Introduction. Data are conflicting when assessing indications for colorectal self-expandable metallic stents (SEMS) in managing acute malignant large bowel obstruction (MLO). In November 2014, European and American Societies published guidelines to aid in understanding which patients might benefit from colorectal stenting. Yet, there remain marked disparities in clinical practice. Methods. A web-based survey was sent to Gastroenterologists and Surgical Specialists across Quebec to assess physicians' knowledge and adherence to the indications for colonic SEMS placement in the management of MLO using eight clinical scenarios. Results. Out of 112 respondents, 74% preferred surgical intervention in young, healthy individuals with MLO. Advanced age and comorbidities motivated 56.3% (95% CI 47.1-65.5%) of participants to opt for SEMS placement. In palliative settings of patients undergoing chemotherapy including bevacizumab, a minority of respondents followed guidelines, 12.5% (95% CI 6.4-18.6%) for young patients and 25.0% for elderly patients (95% CI 17.0-33.0%). The pooled overall adherence to guidelines was 50.4% (95% CI 40.7-59.3%). Conclusion. This survey suggests that guidelines recommendations are not being implemented by at least half of specialists involved in the care of patients with MLO. Future studies should attempt to identify possible barriers responsible for this impaired knowledge translation and tailored educational initiatives planned accordingly

Examination of Physicians’ Perception of the Indications of Colorectal Stents in the Management of Malignant Large Bowel Obstruction: A Provincial Survey

Introduction. Data are conflicting when assessing indications for colorectal self-expandable metallic stents (SEMS) in managing acute malignant large bowel obstruction (MLO). In November 2014, European and American Societies published guidelines to aid in understanding which patients might benefit from colorectal stenting. Yet, there remain marked disparities in clinical practice. Methods. A web-based survey was sent to Gastroenterologists and Surgical Specialists across Quebec to assess physicians’ knowledge and adherence to the indications for colonic SEMS placement in the management of MLO using eight clinical scenarios. Results. Out of 112 respondents, 74% preferred surgical intervention in young, healthy individuals with MLO. Advanced age and comorbidities motivated 56.3% (95% CI 47.1–65.5%) of participants to opt for SEMS placement. In palliative settings of patients undergoing chemotherapy including bevacizumab, a minority of respondents followed guidelines, 12.5% (95% CI 6.4–18.6%) for young patients and 25.0% for elderly patients (95% CI 17.0–33.0%). The pooled overall adherence to guidelines was 50.4% (95% CI 40.7–59.3%). Conclusion. This survey suggests that guidelines recommendations are not being implemented by at least half of specialists involved in the care of patients with MLO. Future studies should attempt to identify possible barriers responsible for this impaired knowledge translation and tailored educational initiatives planned accordingly