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Correa-Mendez F.,University Intercultural Indigena Of Michoacan | Carrillo-Parra A.,Autonomous University of Nuevo Leon | Rutiaga-Quinones J.G.,Universidad Michoacana de San Nicolas de Hidalgo | Marquez-Montesino F.,University of Pinar del Rio | And 3 more authors.
Revista Chapingo, Serie Ciencias Forestales y del Ambiente | Year: 2014

The forest industry in the municipal seat of Nuevo San Juan Parangaricutiro and the Indigenous Community of Nuevo San Juan Parangaricutiro, located in Michoacán state, Mexico, generates 1,232 m3•year-1 of underutilized pine sawdust and shavings. The sawdust and shavings of Pinus leiophylla Sch. Et Cham., P. montezumae Lamb. and P. pseudostrobus Lindl were subjected to physicochemical analyzes to determine if they meet the requirements for pellet and briquette production. The moisture, ash, and inorganic element contents in the byproducts were determined using international standards. Moisture content in ash was 51.5 ± 1.9 %, and 53.7 ± 0.1 % in shavings; these values exceeded the maximum allowable. Ash content in sawdust and shavings was 0.26 ± 0.03 % and 0.34 ± 0.03 %, respectively. For the three species evaluated, the average percentage of calcium, potassium, magnesium, phosphorus, sulfur, silicon, iron, aluminum and sodium in sawdust was 47.1 ± 2.8, 26.0 ± 2.5, 13.5 ± 0.4, 5.0 ± 0.4, 3.2 ± 0.4, 2.3 ± 0.8, 1.0 ± 0.1, 1.3 ± 0.4 and 1.4 ± 0.3, respectively, while the average percentage was 43.2 ± 7.0, 16.5 ± 3.0, 10.1 ± 4.8, 4.0 ± 0.6, 1.8 ± 0.2, 3.6 ± 0.3, 1.0 ± 0.6, 1.1 ± 0.1 and 1.0 ± 0.6 in shavings, respectively. Arsenic was only found in the shavings (17.1 ± 17.1). Based on the results, sawdust is the most suitable byproduct for pellet and briquette production. Source


Rendon-Carmona H.,University Intercultural Indigena Of Michoacan | Martinez-Yrizar A.,National Autonomous University of Mexico | Maass J.M.,National Autonomous University of Mexico | Perez-Salicrup D.R.,National Autonomous University of Mexico | Burquez A.,National Autonomous University of Mexico
Botanical Sciences | Year: 2013

We review published, unpublished, and self-generated information related to the selective extraction of varas (stakes or support poles), and identify some potential effects of the removal of this non-timber forest product on the plant diversity, structure and regeneration of the tropical deciduous forests in Mexico. The varas in highest demand belong to a group of species of Croton (Euphorbiaceae), commercially known as vara blanca, which are widely used as stakes to support plants in horticultural fields. Three economic sectors are involved in the extraction of the vara resource: cutters, contractors, and intermediaries. The intermediaries, who are responsible for marketing the stakes, earn the largest revenues. Technical regulations in Mexico govern the extraction of varas, but they lack sound guidelines that will lead to sustainable use of the resource. Our studies in the Chamela region in Jalisco show that repeated extraction reduces species richness, modifies the structure of the plant community, and increases the relative dominance of Croton septemnervius at the expense of other tree species. Furthermore, after the stakes are cut for harvesting, its vegetative regeneration is limited. The stumps and sprouts exhibit high mortality (> 70%), and the sprouts that survive grow slowly. In order to achieve long-term sustainable management of this forest product, the quality, specificity, and enforcement of the management guidelines require immediate improvement. Also, interdisciplinary studies of tropical deciduous forests management encompassing ecological and socio-economic interactions are urgently needed. Source


Marquez-Montesino F.,University of Pinar del Rio | Correa-Mendez F.,University Intercultural Indigena Of Michoacan | Glauco-Sanchez C.,University of Campinas | Zanzi-Vigouroux R.,KTH Royal Institute of Technology | And 2 more authors.
BioResources | Year: 2015

Pyrolytic degradation of Acacia mangium wood was studied. The chemical composition of biomass, immediate and elemental analyses and calorific value for biomass and char, were determined. The standard and the derivative curve thermogravimetric analysis (TGA and DTG) were obtained. Devolatilization maximum of values between 250±20 °C and 380±20 °C were observed, with completion after 2 h, which confirms the selection of 2 hours for pyrolysis. Kinetic study was performed at different heating rates for a conversion rate from 20% to 80%. Average values of activation energy for temperature in degrees K of 228.57 kJ/mol for Biomass 1 and 199.36 kJ/mol for Biomass 2 were obtained by the isoconversion method of FWO. The lower value of activation energy for Biomass 2 was related to the possible catalytic activity of ash. The values of correlation coefficient from 0.9418 to 0.9946 for Biomass 1 and from 0.8706 to 0.9918 for Biomass 2, indicate the reliability of the first-order reaction model. The caloric values obtained were: Biomass 1 (16962 kJ/kg), Biomass 2 (16974 kJ/kg), chars from Biomass 1 (between 23731 y 26 942 kJ/kg) and gas from Biomass 1 and Biomass 2 (3858.7 and 4859.4 kJ/m3, respectively). Source


Herrera-Arroyo M.L.,National Autonomous University of Mexico | Herrera-Arroyo M.L.,University Intercultural Indigena Of Michoacan | Sork V.L.,University of California at Los Angeles | Gonzalez-Rodriguez A.,National Autonomous University of Mexico | And 4 more authors.
American Journal of Botany | Year: 2013

Premise of study: Anthropogenic fragmentation is an ongoing process in many forested areas that may create loss of connectivity among tree populations and constitutes a serious threat to ecological and genetic processes. We tested the central hypothesis that seed dispersal mitigates the impact of fragmentation by comparing connectivity and genetic diversity of adult vs. seedling populations in recently fragmented populations of the Mexican red oak Quercus castanea. Methods: Adult individuals, established before fragmentation, and seedlings, established after fragmentation, were sampled at 33 forest fragments of variable size (0.2 to 294 ha) within the Cuitzeo basin, Michoacán state, and genotyped using seven highly polymorphic chloroplast microsatellite markers (cpSSRs). To test whether seed dispersal retains connectivity among fragmented populations, we compared genetic diversity and connectivity networks between adults and progeny and determined the effect of fragment size on these values. • Key results: Seventy haplotypes were identified, 63 in the adults and 60 in the seedlings, with average within-population diversity (h S) values of 0.624 in the adults and 0.630 in the seedlings. A positive correlation of genetic diversity values with fragment size was found in the seedling populations but not in the adult populations. The network connectivity analysis revealed lower connectivity among seedling populations than among adults. The number of connections (edges) as well as other network properties, such as betweenness centrality, node degree and closeness, were significantly lower in the seedlings network. • Conclusions: Habitat fragmentation in this landscape is disrupting seed-dispersal-mediated genetic connectivity among extant populations. © 2013 Botanical Society of America. Source


Arnes E.,Technical University of Madrid | Antonio J.,University Intercultural Indigena Of Michoacan | Del Val E.,National Autonomous University of Mexico | Astier M.,National Autonomous University of Mexico
Agriculture, Ecosystems and Environment | Year: 2013

One of the most important challenges for agriculture is addressing high climatic variability by creating productive, resilient and adaptable systems that are highly efficient in terms of water and energy use and having the aims of neither degrading nor contaminating the environment. In Mexico, these characteristics are fulfilled by many seasonal peasant agricultural systems. Systems utilizing native seeds produce an important portion of white maize for human consumption in addition to safeguarding key agricultural genetic resources. This article evaluates the sustainability of such systems and describes the current challenges and opportunities in a representative peasant community in the watershed of Lago de Pátzcuaro in Mexico. Community farming and livestock management practices were analyzed, and ecological, economic and social indicators were measured over a two-year period. During the first year, low-input systems, which are based on the use of organic fertilizers and crop rotation, provided better results in terms of ecological indicators and equal results in terms of economic and social indicators than those achieved using a high chemical input system. In the second year, which featured early frosts and a winter drought, productivity declined in all systems; however, the most diversified systems (in terms of the maize varieties grown and the sowing of other crops) more successfully resisted these climatic adversities. © 2013 Elsevier B.V. Source

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