The genus Cladocolea, commonly called “muerdago verdadero” or “injerto”, is an hemiparasitic plant of trees for a long time unnoticed to Mexican foresters and arborists, in comparison with another true mistletoes. To get an idea on the current importance, species, hosts, distribution, biology and management, this paper was written based on literature review and author’s Experiences. Among the presented information, the effects of some species on vigor and aesthetics of their hosts are emphasized, mainly at the urban areas like Mexico City. It was found that the genus has at least 19 species parasitizing hardwoods mostly, however, conifers can also be infected; the genus Salix is one of the most severely damaged. It was found also that the genus is distributed in at least 11 states of the Mexican Republic. Based on artificial inoculations, it was found that bud flowers can be observed 280 days after inoculation. Finally, results of thousands of pruned Salix bonplandiana trees infected by C. loniceroides are presented, as the first experience in an urban area.

Several aspects on biology of Psyllaephagus bliteus were studied in Chapingo, Mexico. Descriptions of eggs, larvae, pupae and adults are provided. Eggs are deposited inside the abdomen of second or third instar of the host, Glycaspis brimblecombei. Both larvae and pupae of the parasitoid develop inside the nymph body. Sexual dimorphism between male and female are obvious, antennae are strongly different in both sexes. Life cycle of parasitoid requires from 16.3 to 41.6 days to be completed and it is highly influenced by environmental conditions. In rearing cages with Eucalyptus camaldulensis infested with Glycaspis brimblecombei, the average number of parasitoid progeny was 17 new adult per female (minimum 4 and maximum 46) sex rate was lightly favored to female (1.1  :1  ).

The work was developed in the coastal sector of Cortés to the south of Pinar del Rio, Cuba. The objective of this work is to determine the relationship between the dendrometric variables like volume of wood in cubic meters, mean diameter measured at a height of 1:30m, average height and especially the tree density according to Edgar (1994), in number of trees per hectares with the oviposition of the coastal mosquitoes. Twenty-one parcels/blocks were made according to FAO and the Technical Department of the Ministry of the Agriculture (MINAGRI), where, they also took samples of the substratum of the mangrove for the extraction of mosquito eggs according to the methodology of Ritchie and Addison. The correlations patrons between the analyzed variables were determinated through the analysis of the principal components that demostrated the high relation between the oviposition sites and de mangrove structure. The mathematical models Y= e (3.53 +(-5449.12/ number of trees/ha)) was defined to estimate to the quantity of mosquito eggs in function to the number of trees/ha in an adjusted regression coefficient of 0.91.

Biomass production and its association to diversity is an indicator of the health of forest ecosystems, it provides the basis for sustainable management of natural resources. In this research the diversity and production was measured in 15 plots placed in the Tamaulipan thornscrub. Plots were placed in a productivity gradient at five sites with three replicates. In each site three plots were randomly established with dimensions of 5x5 m. All plant cover was harvested for biomass measurements. Shrub and tree diversity was estimated by fitting several diversity indexes. The relationships between production and diversity was established and finally the multivariate statistic detrended canonical correspondace analysis was carried out to observe clusters and patterns in diversity and production. Sites with highest production had the least diversity. This appears to be explained by the presence of the largest number of species of smaller dimensions, by the potential lower nutritional requirements, compartments of usage of resources in time and space, and differential physiological patterns. Indeed the broken stick model of McArthur fitted better the abundance diversity of most plots indicating the late succesional stages of this plant community. The multivariate analysis showed clusters and gradients according to the productivity gradient and geomorphology.

Direct sowing is an economic method to establish programs of forage production with shrub leguminous. Leucaena leucocephala (Lam.) de Wit. is a legume shrub, it has been used in agriculture, cattle feeding and land reforestation, it has great adaptability and has a high forage value, and its employ in agroforestry is commonly. The objective was to establish a direct sowing essay using the systems broadcast, holes and furrows with Leucaena leucocephala, in order to prove its efficiency for to establish fodder banks. The experimental work was carried at Botanical Garden of Forest and Environmental Faculty of Andes University. A completely randomized design with four repetitions and a factorial arrangement (2x3) were used. The experimental factors were Factor A: 1) plowed and 2) no plowed land, Factor B: 1) broadcast sowing, 2) holes sowing and 3) furrows sowing. In this experiment the most successful method was sowing in furrows, as much in plowed as not plowed land. The emergency of Leucaena is between 4th and 18th day after sowed. Three months later the experiment was evaluated, and the greater abundance of plants appeared in the blocks plowed with broadcast sowing system, although the best averages of height growth were in the blocks with plow and sowing in furrows.

A site index estimation was carried out for Pinus chiapensis (Martinez) Andresen, in natural forests in Atzalan, Veracruz State, and Tlatlauquitepec and Yaonáhuac, Puebla State, Mexico. The data base was done with 31 dominant or codominant trees, using stem analysis methodology, to obtain 358 height-age observations. Exponential models: poly-anamorphic with continuous change and polyanamorphic with discrete change; adjusted through non lineal procedures using the SAS system and compared in their polymorphic versions using the algebraic difference method. The Chapman-Richards and Payandeh and Wang and Schumacher models showed a suitable fitting, obtaining pseudo coefficients of determination of 0.98, 0.98, 0.96 respectively. Finally, polymorphic curves were constructed with the two chosen models and three site indexes were established: 20, 25, and 30 m with a base age of 25 years old.

Agroforestry systems are an alternative to improve livestock and agricultural production systems. It is required to identify the multipurpose tree species with potential to be incorporated in the farming production systems. In Camarón de Tejeda, Veracruz the agricultural crisis based in sugar cane production and the reduced profitability of the livestock activity, forces to search for diversified options of production and of reduced environmental impact. In this work a catalogue of multipurpose native tree species present in the production areas was elaborated also within the natural vegetation with the aim of identifying the uses that the people of the region assign to them. Field trips to the region helped the inventorying, collection and identification, and obtain data on the local uses. A bibliographical review to document the potential uses of the inventoried species was elaborated. A list of 38 species was generated, of which 21 report at least one local use. The results reflect the high potential of useful multipurpose tree native species in the area to be incorporated in agroforestry production systems.

An inventory was carried out for woody fuel derived from the harvest in an area of the ejido Pueblo Nuevo, Dgo., Mexico, to determine the loads of forest fuels with danger of causing forest fires. The planar intersect technique was used and the analysis considered the time since last cut, silvicultural treatments, site index, slope and aspect. The results show an increase in the total fuel accumulation from the harvest, reaching the maximum level by the year three. Greater fuel concentrations appear in the treatments of regeneration and thinning, in those areas with the best site quality and moderate slope.

The National Park Zoquiapan and you Annex it is a protected natural surface area that is located to the east of Mexico City, it presents serious problems of ecological imbalance and a strong pressure of the urban area, on the part of the Ixtapaluca municipality, Mexico State. For what is necessary to develop actions that stop, recover, and restore the natural conditions of the environmental, which will be planned, and that better to achieve these objectives, to develop a Territorial Ecological Ordering (TEO). For this proposal TEO the methodology proposed by the Cuban school was used, so much for the establishment and diagnosis of the Geoecologics Units, as well as the analysis multicriterio for the obtaining of the aptitude maps. The information was managed with a Geographical Information Systems Arc/View 3.2. 28 geoecologics units were identified characterized by the altitude, slope, geologic, soil, land cover and land use gives the floor. For each one of them the indexes of potential erosion, protector capacity of the land cover, vulnerability the unit according to their relationship perimeter-area, coefficient, vulnerability for the slope, for the compaction of rock, the degree of anthropogenic modification and the compatibility of the current use with their potential aptitude. With that which the proposals were obtained the Geoecologics Units agreed no for each unit.

The present work contributes to the knowledge of the characteristics and technological properties of the wood of lived Stick (Peltogyne mexicana Martínez), by means of the anatomical characterization, percentage of elements and determination of the physical properties and three certain mechanics were collected two trees in Tierra Colorada Guerrero, the material was obtained from trozas to 1.30 m of height for the macroscopic study samples of 7 x 15 x 1cm were used, for the study microscopic slides of cuts and dissociated material. The wood of intense color violet, diffuse- porous, parenchyma paratracheal banded and confluent aliform with crystals, vessels elements are short with inclusions rays uniseriate, biseriate, triseriate and rarely multiseriate, the libriform fibers medium length, diameter fine and thick wall, this wood has high density, medium shrinkage, it is very hard and flexible