Potencial dendroclimático del encino rojo, Quercus sideroxyla (Fagaceae) en México / Dendroclimatic potential of red oak, Quercus sideroxyla (Fagaceae) in Mexico

Resumen Introducción: Los estudios dendrocronológicos en México se han basado principalmente en las coníferas, mientras que las especies de madera dura han sido poco estudiadas. Este ha sido el caso del género Quercus, con una alta diversidad taxonómica en el país pero que no ha sido estudiado con fines dendrocronológicos, a pesar de los valores ecológicos y económicos de sus especies. Objetivo: En la presente investigación se determinó el potencial dendroclimático de Quercus sideroxyla en el noroeste de México, y su relación con variables climáticas como precipitación y temperatura. Métodos: La investigación se desarrolló en el estado de Durango en el ejido Chavarría Viejo en las coordenadas (23º43' N & 105º33' W), se recolectaron muestras de 5 a 7 cm en dos sitios bajo aprovechamiento forestal y se procesaron mediante técnicas dendrocronológicas convencionales. Resultados: Se desarrolló una cronología de ancho de anillo total, la cual se compuso por 30 muestras de 16 árboles para el período de 1917 a 2018 (101 años). Se obtuvieron valores de intercorrelación entre series de 0.43, de sensibilidad media de 0.36, relación señal-ruido de 3.53 y autocorrelación de primer orden (0.58). En cuanto a la relación clima-crecimiento, los valores de índice de ancho de anillo se correlacionaron con datos de la estación climática más cercana al sitio de estudio; donde la precipitación invierno-primavera (enero-mayo) fue la variable de mayor influencia en el crecimiento de la especie. Conclusiones: Con base en los parámetros dendrocronológicos se demuestra el alto potencial de la especie para ser empleada en estudios dendroclimáticos en la región, la respuesta de la especie a la precipitación es similar al de las coníferas con las que cohabita.

Abstract Introduction: Dendrochronological studies in Mexico have been mainly based on conifers, while hardwood species have been little studied. This has been the case of the genus Quercus, which has a high taxonomic diversity in the country but has not been previously studied for dendrochronological issues, despite the ecological and economic values of oak species. Objective: In the present investigation, the dendroclimatic potential of Quercus sideroxyla in Northwestern Mexico was determined, as well as its relationship with climatic variables such as precipitation and temperature. Methods: The research was carried out in the state of Durango, Chavarría Viejo with coordinates (23º43' N & -105º33' W). Samples of 5 cm to 7cm were collected in two sites under forest exploitation and processed by conventional dendrochronological techniques. Results: A chronology of total ring width was developed, which was composed of 30 samples from 16 trees for the period from 1917 to 2018 (101 years). Inter-series intercorrelation values of 0.43, mean sensitivity of 0.36, signal-to-noise ratio of 3.53 and first-order autocorrelation (0.58) were obtained. Regarding the climate-growth relationship, the ring width index values were correlated with data from the climatic station nearest to the study site, where winter-spring precipitation (January-May) was the variable with the greatest influence on the growth of the species. Conclusions: Based on the dendrochronological parameters, the high potential of the species that were used in dendroclimatic studies in the region has demonstrated that the response of the species to precipitation is similar to that of the conifers with which the Quercus sideroxyla shares its habitat with.

Riqueza, distribución y estado de conservación de las especies de encino en Guatemala / Richness, distribution, and conservation status of the species of oak in Guatemala

Las especies del género Quercus son componentes estructurales de los bosques templados y semicálidos en Guatemala, así como la principal fuente energética en las zonas rurales del país. A pesar de su importancia aún se desconoce la riqueza, distribución y grado de vulnerabilidad de las especies. Por lo cual, se presenta una actualización del listado de especies para Guatemala, su distribución potencial y la evaluación del estado de conservación con base a los criterios utilizados para el listado nacional de especies amenazadas (LEA). Se registraron 29 especies de encinos, 12 corresponden a encinos blancos (Sect. Quercus) y 17 a encinos rojos (Sect. Lobatae), de los cuales Q. cortesii, Q. gulielmi-treleasei, Q. vicentensis, Q. xalapensis se citan por primera vez para Guatemala. Las especies con mayor número de registros son Q. sapotifolia (13%), Q. peduncularis (13%), Q. crassifolia (12%), Q. skinneri (7%) y Q. acutifolia (6.5%), correspondiendo a más del 50% de los registros. Los departamentos con mayor número de registros son Guatemala (177), Zacapa (155), Huehuetenango (134), Baja Verapaz (115) y Chiquimula (93); mientras que departamentos como Retalhuleu, Escuintla y Suchitepéquez presentan menos de 10 registros. En relación al estado de conservación, seis se ubicaron En Peligro Crítico, 22 en la categoría Amenazada y una en la categoría Vulnerable.

The species of the genus Quercus, commonly known as oaks, are important structural components of the forests in the region, as well as a primary source of energy in the rural areas of Guatemala. Despite their relevance, the richness, distribution and degree of vulnerability of the species, are still unknowing. Therefore, it presented an update of the list of species for Guatemala, its potential distribution and the assessment of the state of conservation based on the criteria used for the List of Threatened Species (LEA in Spanish). Twenty-nine species of oak were recorded, of which Q. cortesii, Q. gulielmi-treleasei, Q.vicentensis and Q. xalapensis are cited for the first time for Guatemala. The species with most number of records are Q. sapotifolia (13%), Q. peduncularis (13%), Q. crassifolia (12%), Q. skinneri. (7%) and Q. acutifolia (6.5%), that represent more than 50% of the records. The departments with the highest number of records are Guatemala (183), Zacapa (155), Huehuetenango (134) and Baja Verapaz (115), while departments such as Retalhuleu, Escuintla and Suchitepéquez present less than 10 records. Regarding the state of conservation, the species were evaluated using the methodology of the List of Threats Species of Guatemala, six species were Critically Endangered, 22 in the Threatened category and one in the Vulnerable category.

Cross-Reactivity between Oak and Birch Pollens in Korean Tree Pollinosis

Oak and birch trees belong to Fagales order. Specific IgE to pollen allergens of both trees are frequently found in Korea pollinosis patients. Oak trees which comprise 40% of forest area are common in Korea. However, birch trees are sparse. We compared the allergenicity of pollen extracts of white oak, sawtooth and Mongolian oaks which are prevalent species in Korea, with the pollen extract of birch. The cross-reactivity of four pollen extracts was examined with pooled sera of 12 patients by ELISA, immunoblotting and CAP inhibitions. A protein of 17 kDa, putatively homologous to a major birch allergen Bet v 1, displayed strong IgE reactivity from white oak and sawtooth oak pollen extract but not from Mongolian oak pollen. Notably, a 23-kDa protein from sawtooth and white oaks showed strong IgE reactivity and inhibited by Bet v 1. IgE binding to white oak was inhibited a maximum of 94.6% by white oak, 93.4% by sawtooth oak, 83.2% by Mongolian oak, and 68.8% by birch. Furthermore, sawtooth oak, white oak, and Mongolian oak extracts were able to inhibit up to 78.5%, 76.6% and 67.3% of IgE binding to birch extract, while birch extract itself inhibited up to 94.3%. Specific IgE to Bet v 1 was inhibited a maximum of 79.1% by sawtooth oak, 77.4% by white oak, and 72.7% by Mongolian oak, while 81.5% inhibition was shown by birch. Bet v 1 was able to partially inhibit its homologous molecules from sawtooth oak and white oak in immunoblotting. Birch pollen extract was found to be cross-reactive primarily with Bet v 1-homologous allergen from oak pollens in Korea pollinosis patients. Considering the sparseness of birch tree in Korea, oak, especially sawtooth oak may be the main cause of tree pollinosis in Korea, rather than birch.

Biogeography and conservation of the herpetofauna of the Upland Pine-Oak Forests of Honduras / Biodiversidad y conservación de la herpetofauna de los Bosques de Pino-Roble de la Altiplanicie de Honduras

The upland pine-oak forest herpetofauna constitutes the smallest segment distributed in the major habitat types in Honduras, due to its occurrence at moderate elevations in relatively inhospitable environments, compared to more mesic habitats in the country. This segment, however, is subject to considerable environmental threat as a consequence of annual burning and logging. Of the 356 herpetofaunal species known from Honduras, 105 are known from these habitats. These forests occur throughout much of the mountainous interior of Honduras. They are subject to the Intermediate Dry climate. Four salamanders, 27 anurans, four turtles, 29 lizards, and 41 snakes comprise the herpetofauna. These species are partitioned into restricted, widespread, and peripheral distributional categories. They can be allocated to eleven broad distributional categories, with most belonging to the category containing species whose ranges extend from somewhere in Mexico north of the Isthmus of Tehuantepec to somewhere in South America. The large majority are terrestrial forest inhabitants, arboreal forest inhabitants, terrestrial pondside species, or terrestrial forest pondside species. Most species are judged common, with the next largest group considered to be of infrequent occurrence, and the smallest group of rare occurrence. Upland pine-oak forest species are distributed among four ecophysiographic areas, with the greatest number of species being found in the Southeastern Uplands. Construction of a CBR diagram illustrates that the herpetofaunas of the Northwestern and Northeastern Uplands, the Northeastern Uplands and Southeastern Uplands, and the Southeastern Uplands and Southwestern Uplands are about equally related to one another. The greatest significance of the upland pine-oak forest herpetofauna lies in the relatively high percentage of members presently possessing stable populations, indicating their apparent greater ability to resist anthropogenic habitat...

La herpetofauna de los bosques de pino-roble del altiplano constituye el segmento más pequeño distribuido en los habitats principales de Honduras, debido a su ocurrencia a elevaciones moderadas en ambientes relativamente inhóspitos, especialmente comparados a los ambientes más húmedos de país. Este segmento, sin embargo, está sujeto a una amenaza ambiental considerable, debido a las quemas anuales y a la tala de árboles. De las 356 especies de herpetofauna conocidas en Honduras, 105 son de estos habitats. Esta clase de bosques es prevalente en gran parte del interior montañoso de Honduras. Están sujetos al clima Seco Intermedio. La herpetofauna consiste de 4 salamandras, 27 anuros, cuatro tortugas, 29 lagartijas, y 41 serpientes. Estas especies se clasifican en categorías de distribución restrictas, extensas, y periféricas. Es posible colocar estas especies en once categorías de distribución, con la mayoría encontrándose en la categoría que contiene las especies cuyos rangos se extienden desde alguna parte de México al norte del Istmo de Tehuantepec hasta alguna parte de Suramérica. La gran mayoría son habitantes terrestres del bosque, habitantes arbóreos del bosque, especies terrestres de la orilla de estanques de agua, o especies terrestres del bosque encontradas a la orilla de estanques de agua. La mayoría de las especies se consideran comunes, con el próximo grupo más grande considerado como de ocurrencia poco frecuente, y el grupo más pequeño de rara ocurrencia. Las especies de bosques de pino y roble del altiplano están distribuidas en cuatro áreas ecofisiográficas, con el mayor número de especies encontradas en los altiplanos del sureste. La creación de un diagrama de Coeficientes de Semejanza Biogeográfica (CBR por sus siglas en inglés) ilustra que la herpetofauna de los altiplanos del noroeste y del nordeste, la de los altiplanos del nordeste y del sureste, y la de los altiplanos del sureste y del suroeste, están relacionadas...