Structure and phenology characterization of four tree species of tropical deciduous forests: Characterization, structure and phenology of tree species of the Selva Baja Caducifolia in Morelos

Objective: Determine structural and phenological characteristics of four important tree species in the Low Deciduous Forest Design/Methodology/Approach: To determine the structure, trees ≥ 10 cm in diameter at a height of 1.30 m were censused in 30 sites of 500 m2. For phenology, seven sites were selected. The phenological states evaluated were: rest, vegetative, flowering, fruiting and seeding. Results: 405 individuals were found, belonging to the four species under study Copal ancho (Bursera copallifera (Sessé & Moc.) ex DC. Bullock), Palo dulce (Eysenhardtia polystachya (Ortega) Sarg.,) Tecolhuixtle (Mimosa benthamii (J.F. Macbr. var. benthamii)), Tepemezquite (Lysiloma divaricatum (Jacq.) Macbride), regarding the Relative Importance Value Index, Tepemezquite ranked first, in the phenological aspects observed, three species lost foliage at some time of the year. Only Tecolhuixtle presented it continuously. Limitations on study/implications: The results and conclusions are limited to the sample used in the present study. Since data was only taken from individuals with DAP ≥ 10 cm, but they can be extrapolating exercising care Findings/conclusions: The structural and phenological aspects of the four woody species, in the Ejido El Limón, confirm that they are similar to what has been described for this type of vegetation in other locations in Mexico.Objective: To determine the structural and phenological characteristics of four major tree species in the tropical deciduous forests. Design/Methodology/Approach: To determine their structure, ≥ 10 cm wide trees were registered at a height of 1.30 m in 30 sites of 500 m2. For phenological purposes, seven sites were selected. The following phenological stages were evaluated: dormancy, vegetative, flowering, fruiting, and seeding. Results: Four hundred and five individuals belonging to the four species under study were found: copal ancho (Bursera copallifera (Sessé & Moc.) ex DC. Bullock), Mexican kidneywood (Eysenhardtia polystachya (Ortega) Sarg.), tecolhuixtle (Mimosa benthamii (J.F. Macbr. var. bentha-mii)), and tepemezquite (Lysiloma divaricatum (Jacq.) Macbride). Tepemezquite ranked first according to the Relative Importance Value Index. Based on the phenological characteristics observed, three species lost foliage at some time of the year and only tecolhuixtle was evergreen. Study Limitations/Implications: The results and conclusions are limited only to individuals with ≥ 10 cm in diameter. Further results can be extrapolated from this data. Findings/Conclusions: The structural and phenological features of the four species evaluated in ejido El Limón have similar characteristics to those that have been described for this type of vegetation in other locations in Mexico

Estructura, riqueza y diversidad de especies de árboles en un bosque tropical caducifolio de Morelos

Por su vecindad con la Ciudad de México, que es el núcleo con mayor población del país, el estado de Morelos ha recibido una considerable presión sobre sus recursos forestales; el bosque tropical caducifolio es uno de los tipos de vegetación más impactados. A fin de conocer el estado de conservación de esta asociación, se realizó un estudio en el que se describe la estructura, riqueza y diversidad de especies de árboles en el municipio Tepalcingo de dicha entidad. Se censaron todos los árboles con un diámetro normal ≥ 10 cm en 34 sitios de muestreo de 500 m2 con una separación mínima entre ellos de 200 m, los cuales se ubicaron mediante un plano georreferenciado, que se cotejó en campo; cada uno de ellos fue identificado con estacas y una zanja en cruz en el centro, para facilitar su localización y remedición posterior. Los resultados indican la presencia de 883 individuos, pertenecientes a 50 especies y 20 familias, entre las cuales sobresale Fabaceae. Respecto al Índice de Valor de Importancia (IVI) destacan como taxa principales Lysiloma divaricatum (61.1), Amphipterygium adstringens (28.5), Conzattia multiflora (27.1), Mimosa benthami (21.5), Bursera copallifera (18.03); los valores de los índices de diversidad indican tendencias similares a las descritas para el número de especies

Volcàn de Colima dome collapse of July, 2015 and associated pyroclastic density currents

During July 10th–11th 2015, Volcán de Colima, Mexico, underwent its most intense eruptive phase since its Subplinian–Plinian 1913 AD eruption. Production of scoria coincident with elevated fumarolic activity and SO2 flux indicate a significant switch of upper-conduit dynamics compared with the preceding decades of dome building and vulcanian explosions. A marked increase in rockfall events and degassing activity was observed on the 8th and 9th of July. On the 10th at 20:16 h (Local time = UTM − 6 h) a partial collapse of the dome generated a series of pyroclastic density currents (PDCs) that lasted 52 min and reached 9.1 km to the south of the volcano. The PDCs were mostly channelized by the Montegrande and San Antonio ravines, and produced a deposit with an estimated volume of 2.4 × 106 m3. Nearly 16 h after the first collapse, a second and larger collapse occurred which last 1 h 47 min. This second collapse produced a series of PDCs along the same ravines, reaching a distance of 10.3 km. The total volume calculated for the PDCs of the second event is 8.0 × 106 m3. Including associated ashfall deposits, the two episodes produced a total of 14.2 × 106 m3 of fragmentary material. The collapses formed an amphitheater-shaped crater open towards the south. We propose that the dome collapse was triggered by arrival of gas-rich magma to the upper conduit, which then boiled-over and sustained the PDCs. A juvenile scoria sample selected from the second partial dome collapse contains hornblende, yet at an order of magnitude less abundant (0.2%) than that of 1913, and exhibits reaction rims, whereas the 1913 hornblende is unreacted. At present there is no compelling petrologic evidence for imminent end-cycle activity observed at Volcán de Colima