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

An explicit growth and yield system (GYS) was fitted to data from re-measured plots of Cedrela odorata (spanish cedar) and Tabebuia donnell-smithii planted at the Oaxaca’s coastal region. As a first stage, a total and merchantable volume system at tree level was fitted based on non-destructive sampling scheme. Afterwards a GYS was fitted using seemingly unrelated regression to achieve full compatibility among prediction and projection models. 

Forest nursery production in containers in México mainly uses peat moss, vermiculite and agrolite (standard mixture). Sawdust and pine bark are subproducts of the forest industry which can be used as substrates. The objective of this work was the characterization of five mixtures using pine bark, sawdust, peat moss, vermiculite. Evaluation included physical (bulk density, total porosity, air porosity and easily available water) and chemical (pH, electrical conductivity and cation exchange capacity) characterization. Bulk density varied from 0,31 to 0,51 g m- 3 while the standard mixture was 0,15 g m- 3. Total porosity varied from 77 to 91% compared to the standard mixture with 84%. Air porosity varied from 8 to 20% compared to the standard mixture with 8%. Easily available water varied from 4,8 to 9,9% compared to the standard mixture with 17,7%. pH of the mixtures with bark and sawdust varied from 4,52 to 7,70 while the standard mixture was 3,87. Electrical conductivity varied from 1,84 to 2,69 ds m- 1 while the standard mixture was 1,13 ds m- 1. Cation exchange capacity varied from 43,6 to 89,4 meq/100 g while the standard mixture was 60,4 meq/100 g. Physical properties of mixture 4 (20% of bark + 80% of sawdust) are similar to standard mixture, but not the chemical properties. This mixture is a promising substrate for forest nursery production.

The proportion of Ips galleries with respect to other bark beetles (Pityophthorus, Hylastes, Hylur gops) and larvae of Cerambycidae was analyzed through logistic regression in its interaction with tree diameter and three variables of damage by fire (crown scorch classes, bole char height and live crown length). Ips gallery proportion diminishes as tree diameter and bole char height increase, whereas that proportion grows with the increment in live crown length. In trees with totally scorched crown, but with live terminal buds, the proportion of galleries of woodborer insects increases and the same happens at increasing bole char height in trees with diameter superior to 30 cm.

The effect of interspecific competition on the dynamics of temperate forests in Mexico has rarely been investigated. In this study, the dynamics of an oak forest in the Sierra Madre Oriental are described using techniques involving strong inference. In particular, methods are presented to determine which species are important in the tree community, the sequence of establishment of these species, the competitive replacement of one species by another and, finally, how each species’biology affects their succesional status. The results show a sequence of three species of red oaks (Quercus coccolobifolia, Q. cras sifolia and Q. affinis) replacing one another over time with a fourth species, a white oak Q. obtusata, f u n ctioning as a subdominant to Q. affinis in the late succesional stage of the forest.

This research investigated the usefulness of the Recreation Opportunity Spectrum (ROS) for managing forest recreation in two natural protected areas of southern Durango, Mexico. We used onsite interviews to document the recreation activities visitors participated in, the characteristics of their preferred recreation sites, and socio-demographic information. A cluster analysis identified visitor groups based on the characteristics of preferred recreation sites and the resulting clusters were compared to the recreation activities and socio-demographic data to create a typology of visitors. We used the ROS framework to identify three classes in each natural protected area including (1) zones with easy access and basic facilities (ROS rural class), (2) natural-appearing zones with few facilities (ROS roaded class), and (3) reserve zones (ROS semiprimitive non-motorized or primitive class). Overall, the ROS framework appears to fit appropriately in these two case studies and could be used for recreation planning purposes in other forest areas of the country.

The development of equations to predict yield and production of Pinus rudis Endl. is described. The data for model development were obtained from two measurements of a set of permanent plots located in Aloapan, Oaxaca. The prediction model is a whole stand model with a projection of diameter classes through the Weibull distribution. Stand´s attributes are predicted with both, explicit and implicit predictions. The explicit prediction is based on modifications to the basal area and volume compatible growth models. The implicit prediction is made by recovering the diameter distribution predicted through the parameter prediction method. All growth models, even those related to the Weibull distribution parameter prediction showed an excellent goodness to fit.

The wood anatomy of Oecopetalum mexicanum Greenm. & C. H. Thomps. is described for the first time. This species grows in the forest and coffee ecosystem of the sierra de Misantla, Veracruz, Mexico. In order to recommend possible uses, mechanical properties essays of different types were carried out. These were: bending, like stress at proportional limit, unit work to proportional limit, modulus of elasticity, modulus of rupture, and unit work to maximum load in bending; parallel compression to grain, like maximum strength, stress at proportional limit and modulus of elasticity. All these essays were performed in green wood condition. For each sample, specific gravity was obtained. Vessel diameter, density and distribution, and estimation of abundance and distribution of axial and radial parenchyma were measured from permanent slides. Fiber and vessel elements length, as well as cell contents, were determined from macerated wood samples. Anatomical descriptions were made according to the IAWA List of microscopic features for hardwood identification ( IAWA 1989). The results so far obtained suggest that el cachichín wood is as resistant as pine wood and, for some mechanical properties, this is better than pine wood. Therefore, it is apt as building material, provided the whole bole is used; only if dimensions allowed, it could be saw for making prismatic pieces.

The potential climatic areas for the distribution of red cedar (Cedrela odorata L.) were obtained in the state of Hidalgo under actual conditions, with meteorological information of 1961-1990 as base line, and under climate change conditions wich were obtained with two models: GFDL-R30 and HadCM3 for two time scenarios (2020 and 2050). The adjustment rates in temperature and rainfall obtained for each model were applied on climatic influence areas delimitated according to Gómez et al. (2006). Asoil moisture balance in the state’s surface was calculated under current and climate change conditions using the Thornthwaite, modified version III methodology (Monterroso and Gómez, 2003). The present percentage of the state surface with the vegetation types associated with red cedar is of 9,8% and the surface percentage estimated with some degree of suitability for this specie, using the climatic characteristics of the baseline scenario, is of 30,4%. The results of applied GFDL-R30 model shows an increment on the total surface with some degree of suitability with respect of the baseline scenario of 3,1% and 4,4% for the years 2020 and 2050, respectively, with a differential increment within the suitability classes. The surface estimated with some degree of suitability applying the HadCM3 model shows a decrement of 0,9% for the year 2020 and 0,2% for 2050. However, the class of Moderate suitable, change from 10,5% on the baseline scenario to 0% and 1,3% for the years 2020 and 2050, respectively, with almost all the areas in the lowest level of suitability. 

An experiment was made to know the abiotic factors effect on the development of primary roots, growth and survival of red mangrove propagules (Rhizophora mangle L.). 180 propagules were collected at the Santa Clara swamp, in the North coast of Yucatan, Mexico, forming 6 groups of 30 individuals. Propagules were placed in orifices of a white exponded polyestirene sheet, maintaining them during 48 days in plastic containers, with a vertical position and with hipocotil immersed in water. There were considered three salinities: freshwater (5-7 ups), sea water (30-40 ups) and hypersaline water (70-75  ups), and two conditions of illumination (shade and direct solar radiation) with a maximum Albedo, representing a total of six treatments. Plants under shade conditions (SD, SM and SH) presented a survival of 100%, whereas the treatments exposed directly to solar radiation (LD, LM and LH) presented an inverse survival to the water salinity. Roots development was gradually less when increasing the salinity, intensifying when the propagules were exposed to direct radiation and a greater temperature of the water. The propagules at the shade-freshwater treatment (SD), presented a greater gain of weight due to the development of roots and leaves (only in this treatment leaves were developed). Salinity is the factor that controls the roots production in the R. mangle propagules at the establishment stage. Insolation and temperature cause an increase of physiological stress in the propagules, diminishing the production of roots and increasing mortality.

Forest fires have had a remarkable relevance since the extraordinary fire season in 1998, due to their direct contribution to deforestation, changes in forest structure, species composition, and recently to their impact on the increment of carbon dioxide in the atmosphere. Nevertheless, there is a lack of detailed information about fire impact on forest structure, species composition, and forest dynamics in the Sierra Madre Oriental (SMO). In order to explain possible changes in those factors, this study has examined a chronosequence (134 years), which was determined by analysing tree ring samples in post-fire cohorts of different ages. The objectives of this study were to: (1) determine forest fire historical range of occurrence, (2) quantify present forest structure and tree species composition along a fire chronosequence in order to determinate reference areas to assist restoration programs, and (3) increase the understanding of disturbance patterns in mixed pine-oak forest in this region. The study revealed significant differences between post-fire cohorts in terms of woody species richness, stand composition, and structure. High tree diversity was generally found in young stands, while the intermediate and major ones showed the lowest diversity. In old stands, tree diversity was increased again.