Aplicación de técnicas dendrocronológicas en pinus pseudostrobus lindl. y quercus canbyi trel. Para analizar la influencia climática y el cambio de uso de suelo

El presente estudio se realizó en el municipio de Iturbide, Nuevo León, con el objetivo de evaluar el potencial dendroclimático de las especies P. pseudostrobus Lindl. (Pino) y Q. canbyi Trel. (Encino). Las cronologías realizadas para el pino y el encino, presentan una correlación entre series de 0.702, 0.62, una sensibilidad media de 0.408, 0.478 y una autocorrelación de primer orden de 0.729 y 0.126, respectivamente; el análisis climático indica que las dos especies tiene una respuesta significativa a la precipitación estacional de enero-julio, con una influencia sobre el crecimiento de la madera tardía del encino y en la madera temprana del pino

Effect of organic and conventional systems used to grow pecan trees on diversity of soil microbiota

Agronomic management modifies the soil bacterial communities and may alter the carbon fractions. Here, we identify differences in several chemical and biological soil variables, as well as bacterial composition between organic (Org) and conventional (Conv) agronomic management in pecan (Carya illinoinensis) orchards located in Coahuila, Mexico. The analyzed variables were pH, N, P, K, soil organic matter, organic matter quality, soil organic carbon, C/N ratio, carbon fractions, microbial biomass carbon, easily extractable Glomalin, colony-forming units, CO2 emissions, and the enzyme activity. The DNA of soil bacteria was extracted, amplified (V3-V4 16S rRNA), and sequenced using Illumina. To compare variables between agronomic managements, t tests were used. Sequences were analyzed in QIIME (Quantitative Insights Into Microbial Ecology). A canonical correspondence analysis (CCA) was used to observe associations between the ten most abundant phyla and soil variables in both types of agronomic managements. In Org management, variables related to the capture of recalcitrant carbon compounds were significant, and there was a greater diversity of bacterial communities capable of promoting organic carbon sequestration. In Conv management, variables related to the increase in carbon mineralization, as well as the enzymatic activity related to the metabolism of labile compounds, were significant. The CCA suggested a separation between phyla associated with some variables. Agronomic management impacted soil chemical and biological parameters related to carbon dynamics, including bacterial communities associated with carbon sequestration. Further research is still necessary to understand the plasticity of some bacterial communities, as well as the soil–plant dynamics.Fil: Cabrera Rodríguez, Alejandra. Universidad Autónoma de Chapingo; MéxicoFil: Nava Reyna, Erika. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias; MéxicoFil: Trejo Calzada, Ricardo. Universidad Autónoma de Chapingo; MéxicoFil: García de la Peña, Cristina. Universidad Juárez del Estado de Durango; MéxicoFil: Arreola Avila, Jesús G.. Universidad Autónoma de Chapingo; MéxicoFil: Collavino, Mónica Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Vaca Paniagua, Felipe. Universidad Nacional Autónoma de México; MéxicoFil: Díaz Velásquez, Clara. Universidad Nacional Autónoma de México; MéxicoFil: Constante García, Vicenta. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias; Méxic

Variabilidad hidroclimática reconstruida con anillos de árboles para la cuenca Lerma Chapala en Guanajuato, México

El conocimiento histórico del clima es básico para entender sus variaciones y tendencias en el tiempo. En este estudio se desarrollaron seis cronologías de anillos de árboles, con una extensión cercana a 250 años, en el área de Guanajuato, Jalisco y Querétaro, dentro de la cuenca Lerma Chapala. Se utilizaron dos especies para este propósito: Taxodium mucronatum y Pinus cembroides. Se desarrolló una reconstrucción estacional de precipitación invierno-primavera (enero-mayo) del periodo 1770-2007, para la región centro-sur de Guanajuato; mientras que para el noroeste del estado, se generaron dos reconstrucciones de precipitación estacional, una para el periodo marzo-septiembre y la otra anual (enero-diciembre), con una extensión de 208 años (1790-2007) y 158 años (1850-2007), respectivamente. En las reconstrucciones estuvieron presentes eventos hidroclimáticos severos reportados en archivos históricos por producir carestía de alimentos, hambrunas, brotes epidémicos, migraciones y otras calamidades, como las sequías de las décadas de 1860, 1890, 1920, 1950, 1970 y 1990, lo que corrobora la veracidad de las mismas. Un análisis del efecto histórico de ENSO en la disponibilidad de lluvia, índice de ancho de anillos y producción de cultivos de temporal, mostró alta inconsistencia en su impacto y sólo aquellos eventos de alta intensidad tuvieron influencia en la variabilidad de la precipitación. Dicho comportamiento enfatiza la necesidad de investigar con más detalle otras variables climáticas que, aunadas al fenómeno ENSO, pudieran explicar la variabilidad hidroclimática en esta región

An intensive tree-ring experience: Connecting education and research during the 25th European Dendroecological Fieldweek (Asturias, Spain).

The European Dendroecologial Fieldweek (EDF) provides an intensive learning experience in tree-ring research that challenges any participant to explore new multidisciplinary dendro-sciences approaches within the context of field and laboratory settings. Here we present the 25th EDF, held in Asturias, NW Spain, in summer 2014. The course, with 33 participants and 10 instructors from 18 countries included advanced training in dendrochronology skills, an overview of tree-ring broad fields and methodological basics to deal with specific research questions as well as applied advanced micro-projects in dendroarchaeology (DAR), dendroclimatology (DCL), dendrogeomorphology (DGM), forest dynamic (FD) and plant anatomy (PA). The results demonstrated the potential of tree-ring research in the Asturias region. The DAR group researched archaeological samples from different contexts (Oviedo cathedral choir stalls, Segovia cathedral roof timbers, Ribadeo shipwreck ship timbers and Bronze Age site charcoal) and explored the supply of wood in different periods. The DCL group established that the Quercus robur and Castanea sativa ring-width measurements show weak climate-growth correlations, where for many trees this is likely caused by management. The strength of the climatic signal could be enhanced using undisturbed settings. The DGM group found that Corylus avellana and Salix spp. are challenging species for dendrogeomorphological studies. Debris-flow events were detected by the presence of tension wood, growth reduction and scars, and their incidences were also supported by local meteorological data. The FD group found that tree growth decreases with increasing competition, a pattern more pronounced in C. sativa than in Pinus sylvestris forest plantations. The results indicate that wood production could be increased by applying thinning treatments on C. sativa. The PA group showed that xylem conduits and phloem area are organized according to the common needs for water supply to leaves and obtain photosynthetic products, regardless site growing conditions for P. sylvestris and Tusilago farfara. In conclusion, this EDF has been a model for interdisciplinary research and international collaboration that has demonstrated that high-quality research and education can be conducted within one week. The EDFs provide an important service to the dendrochronological community and demonstrate the usefulness of this educational-scientific and multi-cultural experience