Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The conservation of cocoa agroforestry systems (SAFC) in Tabasco, Mexico, requires the revaluation of their environmental functions, since they represent relicts of arboreal vegetation in a landscape dominated by cultivated areas. For this reason, a research was developed to evaluate the diversity, arboreal structure and carbon stored in the SAFC, according to age, soils and municipalities. For that, the SAFC were inventoried to determinate the diversity through the indexes Shannon-Wienner and Sorenson respectively, arboreal structure through the importance value index, diametric classes and height, as well as the aerial biomass estimated through allometric equations, with which the carbon contents were calculated. We identified 24 families, 37 genera and 39 species. The SAFC > 40 years have slightly more diversity and arboreal density. Based in the age of the SAFC, the arboreal diversity and structure is highest in the SAFC ≥ 40 years with respect to SAFC > 10 years - 15 years and SAFC > 20 years - 35 years; while as with respect to soil group, the aforementioned indicators are higher in the Gleysols, followed by the Fluvisols, Cambisols and Vertisols. The age and soil type determine the carbon stored in the aerial biomass. 75% and 25% of the C of aerial biomass is stored in shade trees and cocoa, respectively. It is concluded that the SAFCs in Tabasco are similar in diversity and tree structure. The older ones established in Fluvisols are slightly more diverse and register a larger basal area, so they store more C in the aerial biomass.

In this paper, procedures are proposed for determining the technical, economic and technical-economic rotations in forest plantations. The classical criteria of maximum productivity were determined: annual average increase and maximum land expected value. For the determination of the rotations, in addition to using the analytical tools (by adjusting forest growth models) and graphical tools conventionally used, mathematical programming models were proposed: model R-01 based on integer linear programming for the determination of the mono-criteria rotations and the models R-02 and R-03 based on weighted integer goal programming and lexicographic integer goal programming, respectively, for multi-criteria rotation determination. The validity of the proposed models was verified through the consistency of the technical, economic and technical-economic rotation ages determined by diverse site index in Pinus caribaea Morelet var. caribaea Barr. & Golf. plantations. The technically optimal rotations varied between 31 years and 35 years according to the site index and the economically optimal rotations between 18 years and 21 years. It was noticed that the technical-economic rotations are highly influenced by the criterion of greater importance in both approaches. The results found for Pinus caribaea var. caribaea with these approaches indicated intermediate rotations between the technical and the economic ones, these varying between 23 years and 25 years.

The productivity of forest systems in the Mexican tropics has been severely constrained by the lack of silvicultural practices that promote their competitiveness. Red cedar wood is an economically important specie in the Mexican tropics, and little is known about yields and how to improve its productivity. The 3-PG model (Physiological Processes Predicting Growth) allows to predict the growth of a stand even in areas where the species has not grown, estimating the productivity of the site. The present study estimated the growth and effect of nutrition on the species through the 3-PG model from the physiological variables of the species and similar one. Foliage biomass mean diameter at breast height, in the fertilized condition increased when fertilization was considered in the stand. The year five was the one that registered the highest volume in the condition with fertilization (FR = 0.6) of 66.9 m3 ha-1 vs without fertilization (FR = 0.3), 51.9 m3 ha-1. In addition, the stem volume (m3 ha-1), trunk biomass (Mg ha-1) and height (cm) also increased with the age of the stand in the fertilization treatment. The 3-PG model is applied for the first time in this species and in Mexico, so it is necessary to continue with ecophysiological studies of the species and aspects of nutrition, to achieve a better prediction of growth and to be a useful tool in decision making of forest management.

Dry forests are considered one of the most threatened ecosystems in the tropics due to anthropogenic activities that cause fragmentation and habitat loss. Structural and plant composition data were collected from 265 plots in 35 sites, resulting in the identification of 316 species distributed in 76 families and 222 genera, including 79% eudicot, 15% monocot, 8% monilophytes, and 1% gymnosperms. The vertical and horizontal distribution indicated that the forest is dominated by young individuals. Acacia picachensis (Fabaceae), Eugenia hondurensis (Myrtaceae), and Lysiloma acapulcense (Fabaceae) were identified as the most dominant plant species based on the importance value index. The remaining Agalta Valley’s dry forest represents a unique habitat and is the refuge of many native, rare, and endemic species, including some considered high conservation priority.

In Mexico the commercial substrates more utilized for the forest seedlings production are Peat Moss, agrolite and vermiculite, however, their costs are high which makes the utility margins decrease; therefore, alternative substrates capable of promoting good quality seedlings are sought. The residues from the production of Shiitake mushroom (Lentinula edodes) have not yet been characterized for their utilization in forestry-related uses. In the present research, a physical-chemical and bacteriological characterization of the compost obtained from the residues of Shiitake mushroom production was performed to evaluate seedling nursery production of Pinus pseudostrobus. Compost showed a N content of 1.14 mg kg-1 (1.14 ppm), 0.80 mg kg-1 (0.80 ppm) of K, P 0.18 mg kg-1 (0.18 ppm), 93.60% of MO and an electrical conductivity of 3.82 mS / cm. Additionally, it presented 3.6x104 of CFU/g, being Pseudomonas and Klebsiella the most abundant genus, with 1.08 × 104, representing 60% of the total bacterial load. The Dickson quality index for treatment 3 (Shiitake residue compost 50%+ vermiculite 33% + 33% perlite) was 0.27, exceeding the control treatment (0.24). According to the obtained data, compost made from residues of Shiitake mushroom production, can contribute to the forestry sector for the production of quality seedlings of Pinus pseudostrobus in nursery.

Teponaztlis exhibited in Mexico’s Anthropology Museum are the most emblematic items among Aztec musical instruments. The purpose of this research was twofold: to correctly identify the wood used to manufacture three of the most important instruments of their kind and to perform an acoustic analysis to determine relevant acoustic and musical parameters of these instruments. Wood identification consisted in comparing some anatomical features of teponaztlis to those of known species from a wood collection and other sources. Multivariate analysis shows that species are separated by the percentage of uniseriate and partially biseriate rays at one hand and by fibre wall thickness at the other hand. The results show that the genus Dalbergia was used for these instruments, and the analysis suggests proximity of teponaztlis to Dalbergia palo-escrito, and to D. granadillo. The acoustic analysis was based on digital sound recordings of the instruments played with the under-side cavity closed or open. Results show that musical intervals between the two low and high pitch tones of the instruments are from slightly below a major third, to slightly above a fifth. Tones produced with the under-side cavity closed are slightly shorter in duration, and stronger, in comparison when it is open. Playing one of the two tones faintly produces sound from the other, and also from the sides of the instrument, especially with the under-side cavity open. The musical intervals that are observed in these instruments do not correspond exactly to conventional Western tunings.

Mangrove structure is influenced not only by the magnitude and periodicity of favorable energy inputs (temperature, hydroperiod, tides, sunlight, and nutrients), but also by stressors (salinity, drought, storms, and frost), which may have a diminishing effect on forest structure. In worldwide characterization of mangrove forests, researchers use several structural parameters to inform, compare, classify, and evaluate mangrove communities for both research and management. However, the calculation of these structural parameters involves a multi-step series of protocols and formula applications that are error-prone and time consuming. Using standard mangrove structure methodologies found in the literature, the mangroveStructure package for R was developed to deliver a simple tool to quickly calculate mangrove forest structure based on either plot or plotless methods. Outputs of the package include density, diameter, basal area, height, as well as relative values of density, dominance, frequency, and importance value. Output also includes common structural indices (complexity index and mean stand diameter) and visual representations of relative values, diameter and height histograms, and canopy height distributions along the transect line. This package will be useful to scientists interested in mangrove field surveys and those seeking a better understanding of mangrove ecosystems structural variability. To familiarize users with its many features, the package includes example data sets collected in the mangroves of Darién, Panama, and south Florida, USA.

Some relationships between ray proportions, strength and shrinkage properties and basic density in hardwood species were highlighted. A better understanding of their relationships caused by the variation in moisture content in the hygroscopic domain could be a key factor in determining of wood stability properties and to determine the choice of a specific wood species according to its service life condition. The objectives of this study were (i) to determine the physical properties of various ring porous wood species (ii) and to evaluate the influence of wood rays (according to their proportions and volume) on physical properties of wood and more particularly on the Transverse Anisotropy Ratio for Shrinkage (TARS). This study focused on four ring-porous hardwood species; Castanea sativa, Quercus canariensis, Quercus petraea and Quercus robur, differing by the presence and abundance of their multiseriate wood rays. Basic densities, tangential shrinkages, radial shrinkages and the TARS of heartwood and sapwood from each wood species were determined. Wood-rays’ proportions and volume were measured by the image analysis method, and their influence on the last three shrinkages was investigated. A significant correlation between wood ray proportions, wood shrinkage values and basic density was observed.

Attributes of the shrub and tree species components of the tropical deciduous forest within the Municipality of Querétaro, Querétaro are described. We used a random sampling of 36 sites of natural vegetation with exclusion criteria. Sites were delimited to a 25 m × 25 m quadrant. Within the quadrant, the species of all individuals of the tree and shrub species greater than 150 cm were identified, not taking into account the Cactaceae and Succulents. Measurements were made of the trees: basal diameter, diameter at breast height, total tree height, canopy height and diameter; carbon capture by species was estimated taking into account the climatic site variables, where they grow. Twenty-two species of shrubs and trees were observed, with Acacia schaffneri, Bursera fagaroides, Forestiera phillyreoides, Karwinskia humboldtiana, Dodonaea viscosa and Ipomea murucoides being the most abundant, while the ones with the highest carbon content are species such as: Prosopis laevigata and Leucaena leucocephala and the less abundant were Randia thurberi and Erytrina coralloides. These results are indispensable for developing and designing proposals for reforestation and conservation of the tropical deciduous forest.

México is the country with the highest number of Pinus species in the world, with around 49, of which in Durango there are registered 20. Despite being the genus most used as timber, the information about its leaf characteristics is scarce. Studies about foliar anatomy of Pinus, have shown that some features are useful for their classification, therefore in this paper the morphological and anatomical description of the leaves of six species collected in two municipalities in the state of Durango is presented, in order to determine if there are differences between them that may be useful in this sense. Samples were obtained from herborized material, which was hydrated and processed through the paraffin embedding protocol, to obtain permanent slides. The morphological characters studied were: presence-absence, color and length of the sheath; margin, length and diameter of the needles, number of needles per fascicle. The anatomical characters were: shape of the leaf in cross section, number of stomata rows in superficial view and characteristics of epidermis, mesophyll and vascular system. P. leiophyla was the only species with deciduous sheath. Although in all taxa the shape of the leaf was triangular in cross section, there was variation in the opening of the angles and the position on the resin ducts, however no differences were observed between the representatives of the Ponderosae and Australes subsections, which may have taxonomic utility.