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

Oreomunnea mexicana is relict and threatened species; it constitutes a dominant tree element in the foggy forest of the Sierra Juárez, Oaxaca. The species is emblematic and is incorporated into the worldview of the inhabitants of the region, where, in addition, it performs very important ecological functions and ecosystem services. The aim of the present work was to analyze the diversity and genetic structure, as well as to evaluate the spatial genetic structure on a fine scale using molecular markers for in situ conservation activities. Dominant markers called inter simple sequence repeat were used with which individuals from nine populations (25 per population) and 120 individuals from a plot of 400 m2 were analyzed. The results showed high levels of genetic diversity (He = 0.405 ± 0003) and moderate levels of gene flow (Nm = 2.25) and low genetic differentiation (P < 0.001; 8%). The fine spatial genetic structure showed a random distribution, while the kinship analysis exhibited high genetic similarity among the analyzed individuals. High levels of diversity suggest that the species is not genetically degraded, however, due to its fragmented distribution and high environmental vulnerability, it is suggested for its conservation in situ, priority should be given for immediate protection to the populations of El Relámpago (due to its great genetic diversity), the Panteon and the Orquidiario due to its low genetic diversity and the high vulnerability due to anthropic and environmental disturbance.

Leaf Area Index (LAI) is a parameter related to multiple physiological variables and growth in tree species. Its evaluation has been done through direct and indirect techniques; the first one is a destructive test with a higher level of precision, while the indirect technique, being one of rapid development, does not affect the growth of the individual but yields results with lesser precision. Among this group, the optical systems stand out, specifically LAI-2000 and the hemispheric digital photography (FDH), which yields the best results obtained in multiple plant species tests. This work evaluated the use of LAI-2000 and FDH taken with a mobile device, using a fisheye lens, a mobile application and comparing their results with the destructive method. Also, the assessment was made in two cloud covers and four wind speed ranges. The results showed that the best indirect method was the FDH-app with the model IAF = 0.88 IAP + 0.17 with an R2 of 0,83, followed by the IAF-2000 and FDH-Lent. It was found a tendency to underestimate the IAF in partially cloudy coverage between 8% and 60%, regardless of the indirect method, although the FDH-app was maintained as the best method. Finally, it was found that winds ranging bigger than 5 km/h generate variations of up to 60% in the IAF values due to changes in the structure of the treetop generating randomness of the movement of the leaves that infers in the increase of the IAF variability, therefore, decreasing its accuracy.

Populations of forest species with a wide distribution tend to differ in morphological traits across altitudinal gradients. This allows the provisional zoning for conducting seed movement that ensures the adaptation and the best growth of the plants. The pattern of morphological variation associated with altitudinal gradients is not known for many Mexican pine species. Therefore, the altitudinal morphological variation was explored based on the length and width of cones and seeds of 70 Pinus patula plus trees selected in eight populations of Huayacocotla, Veracruz, to establish provisional zones for seeds movement. Analysis of variance and association with geographical variables were performed. Significant variation was recorded between and within populations for all the evaluated characteristics and positive correlation of the altitude with the characters of the cones and the width of the seeds. Based on the variation of cone length and width as well as seed width, we suggest a provisional delineation of two altitudinal seed zones (zone I: 1850 m - 2350 m asl; zone II: 2350 m - 2850 m asl), for the movement of seed and reforestation. It is suggested that the seed collected in each zone is used provisionally in a range of ± 250 altitudinal m from the place of origin, without considering the effects climate change. Considering climatic change, it is suggested an altitudinal upward shift of seed sources of 250 m of altitude to realign to the climate projected for 2030, or 500 m for the one to 2060.

To characterize the spatial variation behavior of the tree attributes of tropical species in agroforestry systems is important for its management, and in this sense, geostatistics stands out for using techniques able of characterizing this variation. In this work, geostatistical methods were used to evaluate and map spatial variability of diameter (dbh) at 1.3 m from the ground level, commercial height (hc) and commercial volume (vc) of trees Swietenia macrophylla King, planted in an agroforestry system in the Brazilian Amazon. The field sampling was carried out based on a grid of 50 m × 50 m, which resulted in 36 systematics point. At each point, a circular plot of 500 m2 was installed to measure the variables dbh, hc. The vc of trees in the portions was estimated with the best equation adjusted to the 108 trees cubing data. Next, the spatial distribution standard of these variable were modeled with geostatistics and ordinary kriging was used to generate maps with predictions and uncertainties of the variables. The Schumacher-Hall’s model resulted in the best equation for the estimation of vc, and the systematic grid was efficient to detect the spatial patterns of these variables, because the adjusted semivariograms models demonstrated the strong spatial dependence on the dbh, hc and vc, being possible, make precise interpolations, generating cross-validation results without trend, mainly for vc that presented the best adjusted theoretical model.

To provide strategies to control an unusual pine sawfly outbreak in Oaxaca, the objective of this study was to identify the species and estimate cocoon density and life cycle of the defoliator. For species identification, we followed the taxonomic classification developed by David R. Smith and coworkers, using adult female and male sawflies. Density was evaluated in 10 sites; on each site, one tree was selected at random. From this tree we defined 1 m2 sampling units at 1 m, 2 m and 3 m from the tree stem. We also proposed a general life cycle based on field data and cocoons kept at laboratory conditions. We identified the presence of Zadiprion howdeni as the invasive sawfly in the region. In Ixtlán, the average density of the cocoons was 37.92 ± 8.63 per m2, with significant differences between plots. No significant differences were found in the average density of the cocoons per m2, regarding tree distance. However, significant differences in cocoon’s numbers were observed between males and females per m2. The sawfly´s longest life cycle stage is as a cocoon and the most sensitive stage of life was the adult. Management strategies are provided for the different stages of sawflies. To consolidate these strategies, it is important to continue gathering basic knowledge of the biology and ecology of this defoliating species.

Wave effect and the shyness phenomenon in Alnus acuminata (Kunth) are canopy parameters rarely studied, but they are important in wood quality for standing trees, therefore, a morphometric modeling of crowns for A. acuminata was carried out in homogeneous forests in the Northern Sierra of Puebla. In 20 rectangular areas of 1000 m2, it was evaluated: total height (TH), diameter at breast height (DBH), crown diameter (CD) and canopy coverage (CC). To the data that did not meet the normality assumption, the Kruskal Wallis test was applied; for those who did, the analysis of variance (ANOVA) was used, with tests of mean comparison by Tukey (α ≤ 0.05). The forest value index was 14.99, whereby its two-dimensional structure is normal, based on the DBH, TH and CC. The average slenderness index was 93.52, making the trees not stable to mechanical damage. The vital space index was 38.92, which is high and shows a better development of the trees with low intraspecific competition. At the canopy level, we observed a pattern that follows a rising wave effect, oscillatory and constant in groups of 10 trees. The shyness phenomenon showed an average crack opening of 27.39 cm between crowns whereby this phenomenon is well-defined for the species. It is concluded that in the cups of A. acuminata, the wave effect occurs because of the inequality in the acquisition of resources, and one way to minimize this inequality is through the phenomenon of botanical shyness.

The evaluation of the complex of forest fuels in forests and jungles constitutes an extremely important advance for the prediction, analysis and control of forest fires. With the objective of characterizing the fuel beds in mangroves of the El Castaño wetland system, La Encrucijada, Chiapas, field measurements were applied and relational data analysis techniques. With this, some indices were calculated for the structure and composition of the forest fuel beds. The biomass of live fuels was quantified using allometric equations; the dead fuels were evaluated applying the planar intersection technique. In this study beds of forest fuels were defined in four types of mangrove, with Rhizophora mangle and Laguncularia racemosa being the most important species in terms of dominance. Canopy fuels in the mangrove of R. mangle presented the highest loads, of biomass (266.67 t ha-1 + 39.58 t ha-1). For dead fuels, there were significant differences in the fuel load of 10 h, being greater in the L. racemosa mangrove swamp (17.21 t ha-1 + 1.11 t ha-1), which represent the greatest potential for the propagation of fire in periods of drought and high temperature. There were no differences in the total load of dead fuels; therefore, the four types of mangrove evaluated have the same capacity to accumulate dead biomass. The results obtained are essential to define the danger of fires.

Ecological niche models allow determination of the habitat suitability of species. The objective of the present study was to determine habitat suitability for Swietenia macrophylla King (mahogany) under two scenarios of climate change in Mexico. For the modeling, the MaxEnt 3.3.3 algorithm was used. The species records of the 2009-2014 National Forest and the Soils Inventory were used as the primary source of information. The predictors were the raster of the observed and representative data interpolations for 19 bioclimatic variables, from 1960-1990, 2050 (average from 2041 to 2060), and 2070 (average from 2061-2080), RCP 4.5, the general circulation model MRI-Worldclim CGCM3 with a spatial resolution of approximately 1 km2, and the Comisión Nacional para el Conocimiento y Uso de la Biodiversidad edaphology raster with a spatial resolution of 90 m2. For the 2050 scenario, a loss of suitable habitat of 39.8% is projected, while for the 2070 scenario this loss is 47.6% compared to the 1960-1990 scenario. It is concluded that under both future scenarios, suitable habitat conditions will remain mainly in the states of Campeche and Quintana Roo, the latter of which will conserve about 50% of the suitable habitat. These results permit the development of strategies for the conservation, use and mitigation of the impact of climate change to ensure the survival and use of mahogany and the ecosystems in which it inhabits.

Decentralization within the forestry sector has relied on Regional Forestry Associations (ARS) and independent Forestry Technicians (PSTF) to implement government policies in Forest Management Units (Umafor). The goal of this study was to describe and analyze the roles played by the National Forestry Commission (Conafor), the Miramar Region Forestry Association (Asirmi) and the associated Forestry Technician in the implementation of the Special Programme for the Conservation, Restauration and Sustainable Use of the Lacandon Rainforest (PESL) in Chiapas between 2010 and 2015. The sample method used was the snowball technique and 49 semi-structured interviews were carried out. This was complemented with participant observation and field trips. Conafor’s participation was increasingly limited to approving (or not) applications for the financing of forestry projects due to budget cuts. The participation of the forestry association was enlisted as a requirement for the approval of projects. The Forestry Technician participated in the promotion, management and operation of the projects. Therefore, his actions were key to the approval of projects for the association and the ways in which these different projects were developed on the ground.

In Mexico, shade-grown coffee agroecosystems form part of the agroforestry landscape and provide shelter for a wide range of biological diversity. However, they are subject to transformation processes derived from the needs of producers and market demands, which affects the configuration of the agroecosystem. The present study aimed to quantify the transformations of land use cover related to coffee plantations in the upper La Antigua river basin, that has occurred over a period of 24 years. The dynamics of change in the coverage of land use and vegetation was analyzed, by generating cartography with the supervised classification technique of the LANDSAT images (TM, ETM, and OLI) of the years of 1993, 2003 and 2017 and the analysis of the factors that have promoted the changes that determine the current configuration of the agroforestry landscape, based on interviews with key stakeholders in the region. The results show that the transformation of the agroforestry systems in shade-grown coffee plantations is caused by land use changes and the government programs implemented in the region. Coffee growing represents one of the main sources of income in the Ecological Corridor of the Sierra Madre Oriental of the state of Veracruz, which requires the development of strategies that guarantee the maintenance and sustainability of this economic activity in the zone to avoid the potential impacts to the local development of the communities, as well as the affectation or loss of the natural ecosystems remaining in the region.