The chemical composition of the wood of Eucalyptus saligna Smith was studied, to three heights of the commercial bole. The samples come from the Forestry Company of Macurijes, of Pinar del Río, province of Cuba. It was, determined the contents of cellulose, lignin, hemicelluloses, ashes, as well as the extractives substances in different solvents systems, using TAPPI Norms The Cellulose was studied by means Differential Scanning Calorimetric (DSC). Lignin was studied by means IR spectroscopy. The results showed great differences in the content of extractives substances increasing with the height of the bole, although the lignin increases apparently towards 85% of height of the commercial bole, the values of the standardized intensities of the IR absorptions less diminish with the height, suggesting a crosslinked structure in more accessible the upper part of the tree, due to the influence of the phenolic extractives in the lignin contents. The cellulose showed structural differences with the height of the bole.

The comparative study, by means of statistical analysis the chemical composition of the wood of E. saligna Smith, Corymbia citriodora and E. pellita F. Muell to three heights of commercial bole (25, 55 y 85 %) in samples coming from Forestry Companies of Macurije and Guanahacabibes in Pinar del Río province of Cuba. The results obtained of the chemical composition, treated by means of for a statistical program SPSS for Window, where all the analyzed variables do not have statistical influences in the chemical characterization of the species. The results show one better grouping with to the species that to the height of the commercial bole between the species. The wood of Corymbia citriodora presents the greater contents of cellulose, minors contained of lignin and extractives substances, being the most attractive species from the chemical point of view to be used in the Industry of cellulose and paper

Eucalyptus leaf explants were used to induce callus and embryos. Gamborg B5 culture medium was used with different concentrations of dichlorofenoxiacetic acid (2,4-D) 0.0, 0.1, 0.3, 1.0 and 3.0 mg·L-1 and Thydiazuron (TDZ) 0.0, 0.1, 0.3, 1.0 and 3.0 mg·L-1 which produced calluses. Thereafter the calluses were subcultured to other medium with different concentrations of glutamine (0.0, 50, 150 and 250 mg·L-1), l-prolina (0.0, 100, 200 and 300 mg·L-1), nitrates (at 25, 50, and 75 %), hydrolyzed casein, (100 and 200 mg·L-1), kinetin (0.1 and 2.0 mg·L-1), indolacetic acid (AIA) at 0.1 mg·L-1 and giberelic acid (GA3) at 1.0 mg·L-1. Differentiation of globular structures or proembryos was assessed using a microscopic stereoscopic WILD TYPE 38700 Heerbrugg, Switzerland with plan lens1X and 10X21 Frequency on calluses appearance was also evaluated. Embryos structure were obtained on Gamborg B5 medium supplemented with thydiazuron at 0.1 mg·L-1on solid medium.

The objective of this research was to establish the symbiotic capacity of ectomycorrhizal fungi with Pinus patula and Pinus greggii. These eight ectomycorrhizal fungi were chosen due to their wide distribution and edibility. The percentages of mycorrhizal short roots varied among species from 9 to 66 %. P. patula and P. greggii seedlings inoculated with Laccaria laccata and Suillus pseudobrevipes respectively exhibited a higher degree of infection, bore more mycorrhiza and developed more abundant external mycelium. The highest mean values of height, dry weight and caliper stem were obtained with seedlings inoculated with Laccaria laccata, Suillus pseudobrevipes and Boletus clavipes which showed better growth compared with the control. Histological examination of these pine mycorrhizas showed an ectomycorrhizal association typical of gymnosperms with an intercellular Hartig net penetrating between several layers of cortical cells.

A research was conducted in order to find out the effects of disturbance gradients as given by different pine regeneration cuttings methods and treatments to the forest floor in phytoparasitic fungi populations in pine/oak forest belonging to communal forests at Ixtlan de Juarez in Oaxaca, Mexico. Three conditions were taken into account: Seed Tree treatment, Seed Tree plus Fire and a Control plot without any treatment. High presence of tree parasitic fungi Armillaria mellea (Vahl.:Fr.) Karsten was detected in treated plots and none in the control ones. Number of A. mellea harvests were more than twice higher in the burned plots than in seed tree method with no fire treatment. This finding is very important because we have to be aware that we can cause problems in seedling survival as we can increase disturbances in the forests.

The objective of this work is guided to offer some considerations to improve the levels of efficiency of wooden conversion of Pinus caribaea var. caribaea in bandsaw to use of a strategy to increase the dimensional quality of the sawn wood starting from the analysis of the behavior of the current dimensions of the same and the variation of the one sawed. We built “Control” software witch allows the determining the good dimensions of having sawed as well as the determination of the variation of having sawed. It has observed that in the sawmills 9exists an undersizing fundamentally in the selections 50, 75, 100 mm; as well as an excessive variation of having sawed. It is necessary to eliminate these deficiencies of the actions correctives witch are directed fundamentally to those parts of machines responsible with the variation of having sawed controlling the court outlines selected by the sawyer.

Was carried out a study on the wildlife of the Sierra del AjusDivisico and Sierra Nevada, localized into the Transmexican Volcanic Belt, in the eastern portion of the Southern limit of the Cuenca de Mexico. The high biological richness of this area, that surrounds the Mexico City, one of the largest metropolis in the world, has survived during decades the urbanization impacts on the forest areas, the forest resources use, pollution, hunting, forest fires, ad cattle raising. Despite this, are unknown many of the factors that regulate the dynamics of the ecosystems in this region In relation to the wildlife, the lack of information is by far more evident. Topics such as species diversity, ecological interactions, organism’s ecosystem function, and stress conditions, have received scarce attention. This research included field work and also bibliographic review, in order of estimating the species richness of mammals, birds, reptiles, and amphibians, their ecological relationships, and the consequences of habitat modification, because of the human activities.

Given the importance of the study of the reactivity of the coal with the purpose of studying their activation; CO2-gasification of to char prepared from slow pyrolysis of Pinus caribaea (Pc) sawdust at temperatures of 750, 775, 800 and 825 °C have been studied by isothermal thermogravimetrics experiments and they were carried out in to system to you modulates you yourself of CI Electronics. From the gasification with CO2 was represented the reactivity graphically in front of values of conversion of the char, indicating an increase of the reactivity with the increase of the gasification temperature, what is explained by the development of the surface area with the advance of the reaction and the catalytic effect from the mineral when increasing their concentration in the substrate. The graphic representation of the of Arrhenius‘s equation for the reactivity, indicates that under the conditions studied an electrobalance, the gasification process happens controlled by the chemical stage, where the apparent activation energy value is of + 234 kJ/mol.

In Mexico, fire is the major cause of loss of forest lands. This is particularly true in the State of Chihuahua where fire is the first cause of deforestation. The time to detection plays a major roll in mitigating these disasters. As a support tool, a rational visibility analysis makes possible the distribution of lookout sites that maximizes the area over which the forest lands can be viewed. In this work, a view shed analysis of the area of sight of lookout tower for detection forest fires in the State of Chihuahua is presented. For this procedure, field data was collected from 32 towers using a mobile map system. After digitizing this data, it was overlaid on a digital elevation model and a map of the national forest inventory of the 2000 year, generating the corresponding coverages. The result of this procedure is the distribution of new strategic sites that will increase the visualization cover.

This work presents with detail the development to estimate a population that change with time (dynamics of populations), complicated with the estimation of the characteristic under study. The involved ideas are more complex than they appear, making them difficult in their use to whom need and study this topic in undergraduate and graduate programs, besides the problems of teaching to explain the essential knowledge to the student which allow him to figure it out how to use it in similar situations whose analysis could be with this technique.