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Eleven populations of Taxus globosa were located and evaluated along of the Sierra Madre Oriental in the States of Nuevo Leon and Tamaulipas, Mexico. A complete inventory of the individuals in all Taxus globosa populations was recorded; data of height, diameter, canopy cover and density were also evaluated. The population data were organized in databases on rank classes into six height categories, seven canopies cover categories and seven diameter categories. A χ² test indicates that all the populations showed a normal distribution. The canopy cover and diameter variables showed higher values in correlation analysis (r = 0.9). The population curve tendency on height, canopy cover and diameter shows that isolated or inaccessible populations of Taxus globosa Las Tinajas, Julilo and La Camotera are the populations with more young individuals than the rest of the northeastern populations. [ABSTRACT FROM AUTHOR]

The tropical dry forest is an ecosystem under strong human pressure. It is found both inland and on coastal dunes. The objective of this research is to identify native tree and palm species growing on dunes that are used by local communities. In this research we carried out surveys and interviews among residents of San Isidro and Colonia La Mancha, in the coast of Veracruz on the use of trees of the tropical dry forest on dunes. Among the 55 registered species, Cedrela odorata, Diphysa robinioides, Enterolobium cyclocarpum, Bursera simaruba, Gliricidia sepium, Tabebuia rosea, Chrysobalanus icaco, Guazuma ulmifolia, Acacia cochliacantha, Brosimum alicastrum, Bumelia celastrina, Cocos nucifera, Maclura tinctoria, Piscidia piscipula, Spondias mombin and Ficus spp. were mentioned by more people. Eighteen uses were recorded, being the most frequent construction of houses (119 mentions), posts for fences and live fences (99), firewood (72) and food (48). Four of the uses mentioned refer to environmental services provided by these plants in the dunes. The species with higher number of uses is Gliricidia sepium and Bursera simaruba is the species in which more parts are used, followed by Gliricidia sepium, Guazuma ulmifolia and Brosimum alicastrum. We also inquired about the parts of the tree being used, the frequency, their sale and local price. Based on the results we suggest a group of species that can be used to increase species tree richness in the secondary growths and grassland on dunes, which will provide wood, forage, etc., to the local inhabitants and help maintain the tree cover of the dunes. [ABSTRACT FROM AUTHOR]

The effect of land use on the structural diversity of Tamaulipan thornscrub in northeastern Mexico was examined. The objective was to determine whether land use modified diversity, ecological indicators, structural and vertical distribution of trees and shrubs. The analysis was performed by comparing three ecosystems with different land use history: extensive cattle grazing, traditional agriculture and clear cutting with 21 year of abandonment. The methodology used was a combination of rectangular sites and a sampling analysis called "structural group of four trees". Results showed differences in diversity, ecological indicators, vertical distribution and dimensional structure. [ABSTRACT FROM AUTHOR]

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). A soil 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. [ABSTRACT FROM AUTHOR]

Se presentan los temas abordados en este número de la revista incluyendo la disponibilidad de agua en zonas desérticas, plantas usadas en los programas de forestación en México y la familia de plantas Myrtaceae y su distribución en México.