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21.
Guillaume Lescuyer 《Small-Scale Forestry》2013,12(1):51-66
In Cameroon, community forests are frequently presented as a relevant option to increase the welfare of rural populations and simultaneously improve local governance and forest resources conservation. But apart from community forests, rural livelihoods also depend on forest areas, designated as ‘domestic forests’ in this article, where local users enjoy informal customary rights. The specific contributions of community and domestic forests to the evolution of the prevailing socio-ecological system are assessed through a diachronic study of a village which is located in southern Cameroon. The Sustainable Livelihoods Framework is used to compare the progress of this social-ecological system between January 2008 and December 2009. The overall evolution of livelihoods was found to be positive during that period. In this case study, domestic forests and community forests are based on complementary models, which are often observed in southern Cameroon. Domestic forests constitute the basis of socio-economic development, while community forests might offer opportunities for a local-level carbon sequestration payment mechanism. 相似文献
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Valentine Lafond Guillaume Lagarrigues Thomas Cordonnier Benoît Courbaud 《Annals of Forest Science》2014,71(2):173-186
Context
Climate change is expected to increase forest vulnerability through disturbances such as windstorms and droughts. Forest managers are therefore investigating strategies to increase forest resistance and resilience, especially by promoting uneven-aged and mixed forests through group selection, and by reducing stand stocking and large trees proportion. However, there is little information on the long-term impacts of these two practices.Aims
The objectives of this study were (1) to develop an original silviculture algorithm designed for uneven-aged management and (2) to use it to assess the effects of the above-mentioned management methods in long-term simulations.Methods
We simulated individual and group selection techniques in order to study the effects of group size, harvesting intensity and their interactions on wood production, stand heterogeneity, and regeneration in mountain spruce–fir forests. We used the spatially explicit individual-based forest model Samsara2 to simulate forest dynamics.Results
Our simulation results confirmed the positive effect of group selection practices on structure diversity and regeneration but not on spruce maintenance. Increasing harvesting intensity enabled forest destocking but decreased structure diversity and led to non-sustained yields for the most intensive scenarios.Conclusion
As adaptation measure, we thus recommend moderate group selection harvesting creating 500 m2 gaps. 相似文献26.
Laurent J. Lamarque Déborah Corso José M. Torres-Ruiz Eric Badel Timothy J. Brodribb Régis Burlett Guillaume Charrier Brendan Choat Hervé Cochard Gregory A. Gambetta Steven Jansen Andrew King Nicolas Lenoir Nicolas Martin-StPaul Kathy Steppe Jan Van den Bulcke Ya Zhang Sylvain Delzon 《Annals of Forest Science》2018,75(3):88
Key message
Direct, non-invasive X-ray microtomography and optical technique observations applied in stems and leaves of intact seedlings revealed that laurel is highly resistant to drought-induced xylem embolism. Contrary to what has been brought forward, daily cycles of embolism formation and refilling are unlikely to occur in this species and to explain how it copes with drought.Context
There has been considerable controversy regarding xylem embolism resistance for long-vesselled angiosperm species and particularly for the model species for refilling (Laurus nobilis L.).Aims
The purpose of this study was to resolve the hydraulic properties of this species by documenting vulnerability curves of different organs in intact plants.Methods
Here, we applied a direct, non-invasive method to visualize xylem embolism in stems and leaves of intact laurel seedlings up to 2-m tall using X-ray microtomography (microCT) observations and the optical vulnerability technique. These approaches were coupled with complementary centrifugation measurements performed on 1-m long branches sampled from adult trees and compared with additional microCT analyses carried out on 80-cm cut branches.Results
Direct observations of embolism spread during desiccation of intact laurels revealed that 50% loss of xylem conductivity (Ψ50) was reached at ??7.9?±?0.5 and ??8.4?±?0.3 MPa in stems and leaves, respectively, while the minimum xylem water potentials measured in the field were ??4.2 MPa during a moderate drought season. Those findings reveal that embolism formation is not routine in Laurus nobilis contrary to what has been previously reported. These Ψ50 values were close to those based on the flow-centrifuge technique (??9.2?±?0.2 MPa), but at odds with microCT observations of cut branches (??4.0?±?0.5 MPa).Conclusion
In summary, independent methods converge toward the same conclusion that laurel is highly resistant to xylem embolism regardless its development stage. Under typical growth conditions without extreme drought events, this species maintains positive hydraulic safety margin, while daily cycles of embolism formation and refilling are unlikely to occur in this species.27.
28.
Cardozo Ernesto Gómez Celentano Danielle Rousseau Guillaume Xavier Silva Hulda Rocha e Muchavisoy Henry Mavisoy Gehring Christoph 《Agroforestry Systems》2022,96(5-6):941-956
Agroforestry Systems - The potential of agroforestry systems (AFS) for atmospheric carbon sequestration in degraded tropical lands is of key interest for climate change and rural development... 相似文献
29.
Guillaume Roblot Damien Coudegnat Laurent Bleron Robert Collet 《Annals of Forest Science》2008,65(8):812-812
30.
Analysis of amino acid uptake and translocation in Arabidopsis with a low‐cost hydroponic system 下载免费PDF全文
In soils, amino acids may be an important source of nitrogen for plants, at least in those where organic matter is not quickly degraded. The physiology of uptake of amino acids by roots was mainly studied in the 70's and 80's, before genes encoding amino acid importers were cloned in the 90's. While two families of amino acid transporters have been identified, yielding a total of about 100 genes, the role of each member is yet to be elucidated. As a tool for studying the role of amino acid transporters from Arabidopsis we set up a new hydroponic system suitable for radioisotope use. This system enables reproducible amino acid uptake by roots and estimation of the transport to the shoots of the amino acid taken up. We show that the rates of glutamine (Gln) uptake by wild‐type roots and transfer to the shoots were linear, and that other tested amino acids were translocated to the shoots with lower efficiency than Gln. A T‐DNA insertion mutant for a Gln exporter was compared to the wild‐type plants. Gln uptake and transfer were similar in both genotypes, showing that the suppression of the exporter did not affect uptake or transfer of amino acids to the shoots. The main advantage of the hydroponic system presented here is that all the materials used to grow Arabidopsis are virtually free and can therefore be discarded, a useful feature when working with radioactivity. 相似文献