Forest Management: are Double or Mixed Rotations Desirable?

In this paper, we study a particular uneven-aged forest stand management pattern that is often advocated in practice. The forest structure under consideration is similar to a normalized forest à la Faustmann, with the following difference: rather than being single aged, each forest tract contains trees of two age classes so that it is submitted to a form of selective cutting. Each harvest involves all of the older trees and only a fraction of the younger ones; hence the name mixed rotation. Trees left standing at harvest help stimulate natural regeneration and improve various environmental and amenity characteristics of the forest. We model this effect by using a cost function that varies with respect to the harvest rate of younger trees. We derive the properties that this cost function must exhibit in order some form of mixed rotation to be superior to the conventional single rotation à la Faustmann; we also characterize the mixed rotation in terms of duration and the harvest rate of younger trees, and we compare its properties with Faustman’s rule. Nous étudions un cas particulier d’aménagement forestier inéquien qui est recommandé dans la pratique actuelle. La structure de la forêt est similaire à une forêt normalisée à la Faustmann avec la différence suivante: au lieu d’être équien, chaque lot comporte deux classes d’âge; il est soumis à une forme de coupe sélective. À chaque récolte, on coupe tous les arbres les plus vieux ainsi qu’une fraction des arbres les plus jeunes; d’où le nom de rotation mixte. Les arbres non coupés aident la régénération naturelle et améliorent diverses caractéristiques environnementales et esthétiques de la forêt. Nous modélisons cet effet en utilisant une fonction de coût qui varie avec le taux de récolte des arbres jeunes. Nous dérivons les propriétés que cette fonction de coût doit satisfaire pour que la rotation mixte soit préférable à la rotation standard à la Faustmann; nous caractérisons la rotation mixte en termes de durée et de taux de récolte des jeunes arbres, que nous comparons avec le cas de Faustmann.forest management, Faustmann’s rule, normal forest, synchronized forest, uneven-aged lots, amenity value, mixed rotation, selective cutting, aménagement forestier, règle de Faustmann, forêt normalisée, forêt synchronisée, forêt inéquienne, aménités, rotation mixte, coupe sélective

Labour and the Environment: A Natural Synergy

This report presents examples of tools and practices that promote workers' health and safety as well as environmental protection, public health, and corporate responsibility. Issues include climate change, hazardous materials

Forest Management : Are Double or Mixed Rotations Desirable?

In this paper, we study a particular uneven-aged forest stand management pattern that is often advocated in practice. The forest structure under consideration is similar to a normalized forest à la Faustmann, with the following difference: rather than being single aged, each forest tract contains trees of two age classes so that it is submitted to a form of selective cutting. Each harvest involves all of the older trees and only a fraction of the younger ones; hence the name mixed rotation. Trees left standing at harvest help stimulate natural regeneration and improve various environmental and amenity characteristics of the forest. We model this effect by using a cost function that varies with respect to the harvest rate of younger trees. We derive the properties that this cost function must exhibit in order some form of mixed rotation to be superior to the conventional single rotation à la Faustmann; we also characterize the mixed rotation in terms of duration and the harvest rate of younger trees, and we compare its properties with Faustman's rule.forest management, Faustmann's rule, normal forest, synchronized forest, uneven-aged lots, amenity value, mixed rotation, selective cutting

Neuroprotective Activity of Grape Seed and Skin Extract Against Lithium Exposure Using Proteomic Research

International audienceLithium (Li) has raised scientific concern because it represents a serious problem threatening human health. This study aimed firstly at analyzing and potentially quantifying the impact of Li and grape seed and skin extract (GSSE) separately and, secondly, describing the possible neuroprotective activity of GSSE against Li toxicity. To this end, rats were exposed for 30 days to different Li concentrations (0, 2, and 100 mg/kg bw), to GSSE (4000 mg/kg bw), and to binary mixture of Li and GSSE. Liquid chromatography (HPLC–MS/MS) analysis used for GSSE showed that 15 phenolic compounds are present in the extract. Significant modifications of proteins were detected in the brain using proteomics research after treatment. Proteins were successfully identified by a linear ion trap–Orbitrap mass spectrometer. These proteins can be roughly related to oxidative stress, glycolysis, signaling pathway, and inflammation. Additionally, proteins involved in cell junction such as myosin, spectrin, tubulin, ERM-binding phosphoprotein, and dynein were also affected by Li exposure. Dose response was detected for most expressed proteins after Li treatment. In contrast, GSSE induced the expression and/or the stabilization of some proteins changed after Li treatment in the brain showing its neuroprotective activity. These data demonstrate that proteomic analysis is a powerful tool to provide valuable insights into mechanisms of toxicity of Li in the nervous system of Wistar rats. To our knowledge, this is the first evidence of using GSSE as neuroprotective model against Li toxicity. These findings provide impetus for future investigation on GSSE against other toxic chemicals

Hepatoprotective effect of grape seed and skin extract against lithium exposure examined by the window of proteomics

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Neuroprotective Activity of Grape Seed and Skin Extract Against Lithium Exposure Using Proteomic Research

International audienceLithium (Li) has raised scientific concern because it represents a serious problem threatening human health. This study aimed firstly at analyzing and potentially quantifying the impact of Li and grape seed and skin extract (GSSE) separately and, secondly, describing the possible neuroprotective activity of GSSE against Li toxicity. To this end, rats were exposed for 30 days to different Li concentrations (0, 2, and 100 mg/kg bw), to GSSE (4000 mg/kg bw), and to binary mixture of Li and GSSE. Liquid chromatography (HPLC–MS/MS) analysis used for GSSE showed that 15 phenolic compounds are present in the extract. Significant modifications of proteins were detected in the brain using proteomics research after treatment. Proteins were successfully identified by a linear ion trap–Orbitrap mass spectrometer. These proteins can be roughly related to oxidative stress, glycolysis, signaling pathway, and inflammation. Additionally, proteins involved in cell junction such as myosin, spectrin, tubulin, ERM-binding phosphoprotein, and dynein were also affected by Li exposure. Dose response was detected for most expressed proteins after Li treatment. In contrast, GSSE induced the expression and/or the stabilization of some proteins changed after Li treatment in the brain showing its neuroprotective activity. These data demonstrate that proteomic analysis is a powerful tool to provide valuable insights into mechanisms of toxicity of Li in the nervous system of Wistar rats. To our knowledge, this is the first evidence of using GSSE as neuroprotective model against Li toxicity. These findings provide impetus for future investigation on GSSE against other toxic chemicals