Forests and poverty : how has our understanding of the relationship been changed by experience?

Understanding of the relationship between forests and the poor has grown enormously, especially in the last twenty years. Aid donors worked on poverty reduction in the forest sector in the 1990s and into the early 2000s, but thereafter broadened their attention to address climate change mitigation, better forest governance and timber legality, and payments for environmental services. There has so far been an incomplete integration of new insights into the nature of poor people's reliance on forests, of their own efforts to use that reliance to escape from poverty, and of current forestry aid concerns. Future projects need to choose interventions which make better use of the results now available about forestpoverty relationships, both for the better conservation of forests, and for better focus on the livelihoods of the forest-reliant poor as they continue to try to move out of poverty.Peer reviewe

Balance model for equatorial long waves

Geophysical fluid models often support both fast and slow motions. As the dynamics are often dominated by the slow motions, it is desirable to filter out the fast motions by constructing balance models. An example is the quasi geostrophic (QG) model, which is used widely in meteorology and oceanography for theoretical studies, in addition to practical applications such as model initialization and data assimilation. Although the QG model works quite well in the mid-latitudes, its usefulness diminishes as one approaches the equator. Thus far, attempts to derive similar balance models for the tropics have not been entirely successful as the models generally filter out Kelvin waves, which contribute significantly to tropical low-frequency variability. There is much theoretical interest in the dynamics of planetary-scale Kelvin waves, especially for atmospheric and oceanic data assimilation where observations are generally only of the mass field and thus do not constrain the wind field without some kind of diagnostic balance relation. As a result, estimates of Kelvin wave amplitudes can be poor. Our goal is to find a balance model that includes Kelvin waves for planetary-scale motions. Using asymptotic methods, we derive a balance model for the weakly nonlinear equatorial shallow-water equations. Specifically we adopt the ‘slaving’ method proposed by Warn et al. (Q. J. R. Meteorol. Soc., vol. 121, 1995, pp. 723–739), which avoids secular terms in the expansion and thus can in principle be carried out to any order. Different from previous approaches, our expansion is based on a long-wave scaling and the slow dynamics is described using the height field instead of potential vorticity. The leading-order model is equivalent to the truncated long-wave model considered previously (e.g. Heckley & Gill, Q. J. R. Meteorol. Soc., vol. 110, 1984, pp. 203–217), which retains Kelvin waves in addition to equatorial Rossby waves. Our method allows for the derivation of higher-order models which significantly improve the representation of Rossby waves in the isotropic limit. In addition, the ‘slaving’ method is applicable even when the weakly nonlinear assumption is relaxed, and the resulting nonlinear model encompasses the weakly nonlinear model. We also demonstrate that the method can be applied to more realistic stratified models, such as the Boussinesq model

Laser operation of an Nd:Gd₃Ga₅O₁₂ thin-film optical waveguide fabricated by pulsed laser deposition

We report the laser operation of a thin-film waveguide structure grown by the pulsed laser deposition technique. A 2.7-µm-thick crystalline film of neodymium doped Gd3Ga5O12 (Nd:GGG) lases at a wavelength centered at 1.06µm when pumped by a Ti:sapphire laser at 808 nm

Climate change and hydrology at the prairie margin : historic and prospective future flows of Canada's Red Deer and other Rocky Mountain river

This projected commenced with support from Alberta Agriculture and the Red Deer River Watershed Alliance, and subsequent funding was provided by Alberta Environment and Parks, Alberta Innovates, and the Natural Sciences and Engineering Research Council of Canada (NSERC), and Agriculture and Agri‐Food Canada provided some climate data. This paper follows from an MSc thesis chapter by the first author, and we extend thanks to faculty advisors Cam Goater, Stefan Kienzle, and Larry Flanagan and to two anonymous reviewers for very helpful recommendations.Peer reviewedPostprin

The environmental, socioeconomic, and health impacts of woodfuel value chains in Sub-Saharan Africa: A systematic map

Background: In Sub-Saharan Africa (SSA), the production and use of woodfuel remains an important socio-economic activity with more than 70% of the population relying on woodfuel as their primary household energy source. Despite their socio-economic significance, woodfuel value chains are often viewed negatively due to their association with detrimental health and environmental impacts. However, the lack of sound evidence and limited understanding of the role of contextual factors in influencing the various impacts of woodfuel value chains have prevented the formulation of properly guided policy interventions. Thus the objective of this systematic map is to provide a comprehensive review of the environmental, socio-economic, and health impacts of woodfuel value chains across SSA. Methods: The search strategy for this review map was defined in a peer-reviewed protocol and refined by iterative testing. Search strings were composed of population, intervention, and location terms and combined using Boolean operators. The bibliographic databases Web of Science, Scopus, and CAB Abstracts were used as the main sources of literature for this review, and a total of 4728 results were initially retrieved. Following title and abstract screening, 659 entered full text screening. Critical appraisal of 219 articles led to the exclusion of studies that did not set meet quality criteria for this map, resulting in a final total of 131 articles for inclusion in data extraction and analysis. Results: From the 131 included articles, 152 individual studies were identified during data extraction. Studies came from 26 of the 49 Sub Saharan African countries, with a particular preponderance of articles published in the last 10 years. Critical appraisal found significant weaknesses in the experimental design of woodfuel value chain studies with the exception of health impact studies, which frequently utilized controls or other relevant comparators. Findings suggest that woodfuel value chains have environmental, socioeconomic and health consequences with the frequent presence of trade-offs. The reporting of contextual factors in the studies challenge the widespread perception of deforestation as being directly caused by bush fires, overgrazing and woodcutting. Instead, agricultural expansion (which often includes forest clearing) and pre-existing biophysical factors were the most frequently cited factors in shaping environmental outcomes. Conclusions: This systematic map suggests that there are environmental, socioeconomic and health consequences associated with woodfuel value chains in Sub-Saharan Africa. However, the literature also shows a weak and geographically limited evidence base to justify the above claims. We argue that policy formulation processes targeting woodfuels in SSA require more solid, coherent and broad body of knowledge, especially for such a vital sector in rural economies. Thus, there is an urgent need to design and undertake research using robust methodologies, at appropriate scales that further takes into account the interrelationships between environmental and socio-economic outcomes in order to generate substantial and reliable evidence for informed policy formulation. (Résumé d'auteur

Formation of Jets and Equatorial Superrotation on Jupiter

The zonal flow in Jupiter's upper troposphere is organized into alternating retrograde and prograde jets, with a prograde (superrotating) jet at the equator. Existing models posit as the driver of the flow either differential radiative heating of the atmosphere or intrinsic heat fluxes emanating from the deep interior; however, they do not reproduce all large-scale features of Jupiter's jets and thermal structure. Here it is shown that the difficulties in accounting for Jupiter's jets and thermal structure resolve if the effects of differential radiative heating and intrinsic heat fluxes are considered together, and if upper-tropospheric dynamics are linked to a magnetohydrodynamic (MHD) drag that acts deep in the atmosphere. Baroclinic eddies generated by differential radiative heating can account for the off-equatorial jets; meridionally propagating equatorial Rossby waves generated by intrinsic convective heat fluxes can account for the equatorial superrotation. The zonal flow extends deeply into the atmosphere, with its speed changing with depth, up to depths at which the MHD drag acts. The theory is supported by simulations with an energetically consistent general circulation model of Jupiter's outer atmosphere. A simulation that incorporates differential radiative heating and intrinsic heat fluxes reproduces Jupiter's observed jets and thermal structure and makes testable predictions about as-yet unobserved aspects thereof. A control simulation that incorporates only differential radiative heating but not intrinsic heat fluxes produces off-equatorial jets but no equatorial superrotation; another control simulation that incorporates only intrinsic heat fluxes but not differential radiative heating produces equatorial superrotation but no off-equatorial jets.Comment: 23 pages, 10 figure