An evaluation the transformation of vegetation that occurred between 1974 and 2000, at river Pilon sub-basin was evaluated through satellite imagery (Landsat MSS and ETM). Interpretation was disregardad into two physiographic provinces and was supervised using digital maps of vegetation and field check. The types of vegetation were mapped and measured in both images in order to compare them. At the coast plains, the most affected communities lost quite much surface: torn scrub (86 %), mesquite scrub (73 %) and sub mountain scrub (32 %). Agricultural lands advanced notoriously over scrubs. At the Sierra Madre, sub mountain scrub lost 73 %, oak forest 43 % and fir forests 35 %. These changes could be related to social and economical dynamics of studied regions.

Because of the purpose of determining the species of mushrooms associated with oaks in areas of natural distribution in the Sierra de Pachuca, Hgo., three sites with oaks as an important structural element in the vegetation of the Northwest part of the region were selected. In each site several plots were marked out for observation, where fructiferous bodies from mushrooms were collected and botanical samples of oak species in Quercus mexicana forest (QMF), fir-oak forest (FOF) and Quercus obtusata forest (QOF), since July to November 2002. Subsequently, species of the collected samples were identified. Registered field data was analyzed through value importance (I. V.) and the species association coefficient, besides the consult of specialists and appropriate literature to identify mushrooms species. Six oak species and 37 species of mycorrhizical mushrooms were registered The FOF presented the smallest mycorrhizical mushrooms species number, but it had the best soil fertility characteristics than others. mycorrhizical mushrooms species with greater I. V. were Lactarius thyinos, Inocybe sororia, Russula paludosa, R. xerampelina, Lycoperdum perlatum, Psathyrella spadicea, Russula aff. olivacea and Lactarius croceus. However, Amanita flavoconia, Clitocibe gibba, Inocybe sororia, Lactarius piperatus, Russula emetica, R. densifolia and R. decolorans showed positive coefficients of association with several oak species.

The present work was carried out in the forest unit of San Andrés, in the area that corresponds to the slates heights and the objective of this work was to make a valuation of different aspects of its morphology and the endemism of in species in woody plants companions in the ecosystems of natural pine groves found in the studied area. To make this valuation they had considered aspects like biological type, the texture of the leaves, the size of the plant, the distribution of species, and the family of the species gathered in the sampling areas. Leaning to the conclusion that the accompanying vegetation is characterized for being species of small to medium size, with fairly small leaf and that there is no endemic in this species at a district level or a local one.

In response to the attempted invasion by pathogens, plants present a broad range of defense responses, including the generation of reactive oxygen species. The most spectacular and one of the earliest observable aspects of this mechanism is the oxidative burst- a rapid and transient production of large amounts of reactive oxygen species.

Dragonflies’ flight, characterized by its peculiar pace and strength, has developed a particular interest in the study of their thoracic muscular structure and it’s wings’ constitution and shape. Due to these features, the advances in the analysis of their flight have significantly contributed to aeronautical and robotic technology.

The objective of this work was to evaluate a group of twelve competition indexes through mathematical models adjusted with the minimum square procedure to estimate each distance independent index of competition to know the competitive status of the trees and forest stand; being this was a numeric relationship that shows in an indirect way the competition for limited resources in that site like: light, water and nutritious and also that both resources have a direct relationship with the growth and yield of the forest species, allowing us to obtain the best index for mixed species and to evaluate them based on their adjustment statistics and the efficiency of the estimators according to the hypothesis test practiced in the mathematical models. Of all evaluated indexes it was shown that the best index which was included in a model of prediction of the increment in diameter, was the index of crown width for density (IACD) because it presented the highest values in the test of ITI, with T = -6.637, also in the hypothesis test its level of accuracy, was highly significant Prob. > ITI = 0.0001.

Systematizing experiences is a process of critical reflection, guided to reconstitute and to organize the results of a project, to understand the factors that have intervened and to extract lessons that allow improving a similar future experience. In this work a systematizing model is adapted to a forest development project with small rural owners in the commune of Litueche, Chile, where the methodological key element is the perception of the involved actors. The perception on the results of the project was much favorable between the direct beneficiaries and the communal authorities, especially on the conservation and management of water, farm management and community organization. However the experience from the project also showed several things that should be improved in future interventions. Although the project used a highly participative focus, the need for a stronger communication among the actors was evident, in order to avoid the non satisfied expectations among the small rural owners, and to obtain the best understanding of the strategy of shared contributions.

Many species of plants have strong attachments with the riparian zones, since they grow throughout the margins of the water. The humid microclimate of the riparian zone and the humidity of the ground, originated by the water outcropping and by the water of the land near the surface, makes them suitable habitats for many small amphibians and some small mammals. From the edge of the water and progressively towards the inside forest, frequently successive bands of vegetation are defined, by means of very small changes in the topography. These ecosystems have many attributes that creates more biological diversity: sequential limits, successional patterns, vertical disposition in layers, special microhabitats defined by their physical characteristics. River minnows, frogs and squirrels, algae, platanus, willows, pines and oaks; all of them thrive the beaches a long the streams.

The present work was carried out with the purpose of knowing the capacity of absorption of wood preservers of Pinus arizonica(white pine), Pinus engelmanni (real pine), Pinus patula (red pine), Ceiba pentandra (ceiba), Manilkara zapota (chicozapote), Spondias mombin (jobo), Quercus oleoides (tesmol), by applying the processes of vacuum-pressure impregnation and immersion with CCA salts type C at 2.5 %, pentachlorophenol (PCP) at 5 % and creosote at a concentration of 5 %. The levels of absorption were analyzed with invariable techniques. According to the levels of absorption reached with the vacuum-pressure method, with the CCA salts, the pines the ceiba and the jobo were easy to impregnate, with pentachlorophenol and creosote only the pines were easy to impregnate. As for the immersion method, with CCA salts the red pine, the ceiba and the tesmol were easy to impregnate; with pentachlorophenol and creosote the oaks chicozapote and jobo were difficult to impregnate. The biggest absorption with CCA salts for the pines, the ceiba and the jobo was reached with the method of vacuum-pressure impregnation and for the oaks and the chicozapote the biggest absorption with CCA salts was reached with the lingering immersion.

Firefighting is a hard and risky work. However, the physical and professional profile of these valuable personal is not accurately known in Mexico. This work presents such a profile, and an index to valuate it. This valuation is based in the age, experience, training and physical characteristics. This work also describes other characteristics of the personal, such as education level, and the most common injures they suffer. For this purpose a survey was carried out on 35.4 % of CONAFOR’s permanent crew bosses, and 10.4 % of firefighters, in all of the 32 states of Mexico. The average values for the firefighter’s population were: 42 years old, 1.69m height, and 79 kg weight (21.9 % is obese), 15 fire seasons of experience, and 1.4 training courses. This proposed index has a maximum value of 100. 98.3 % of the firefighters had scores >60. The most common injuries include fractures, twisting, cuts and knocks. The selection of this personal should follow professional criteria and not labor union decisions, as it currently happens.