Due to the present need to restore plant cover through reforestation and restoration programs that employ native species, the role of nurseries as depositaries and providers of this type of plants has become increasingly important, especially due to present recognition that the propagation of native species is essential to biodiversity conservation. One of the main problems faced by these programs is the availability of material, not only in quantity but also in quality and size. It is quite possible that the success of such efforts towards environmental rehabilitation depends on the correct performance of a procedure running from seed collection and sowing to the establishment and maintenance of plants on a particular site. Presently, nurseries are facing a crisis due to technical, economical, and organizational problems, all resulting in production that is deficient in quality and quantity. After analyzing surveys and interviews of this state’s nursery managers, diagnosis was rendered of the situation that they face and of the productive potential that they have, in an effort to support reforestation and ecological restoration programs.

In Mexico the application of remote sensing techniques is in experimentation. For this reason, appropriate methodology is being generated for the study of land use classification and vegetation of Mexican territory. We conducted a study for the eastern region of the Valley of Mexico, using Landsat TM and Spot XS images, and proceeding with the Personal Interactive System of Remote Perception version 2.0 (SPIPR II), for ten units of classification: irrigation agriculture (AR), rainfed agriculture (AT), halophile grass (PH), forest pine (BP), induced grass (PI), urban zone (ZU), bodies of water (CA), forest pine-grass (BP-PI), oak forest-scrub (BE-MI) and fir forest (BA). Four treatments (principles components, texture analysis, convolution and filtrate) over three combinations of bands (Landsat TM3-TM4-TM5, TM2-TM5-TM7 and Spot XS1-XS2-XS3) were established. As a result, we obtained an accuracy of 75% for the classification of Landsat TM2-TM5-TM7 image without treatment; for Landsat TM3-TM4-TM5 without treatment accuracy was 69.07%, and the classified Spot XS1-XS2-XS3 images with the principle components had an accuracy of 69.06%.

The activities man performs in the environment must be known and regulated in order to carry out correct planning and management of resources. Remote sensing allows the assessment of natural resources and their current problems faster and more efficiently. The present study was conducted in the Valle del Mezquital, in the state of Hidalgo, which has problems of pollution from wastewater used to irrigate farmlands. Land was evaluated and classified by level of nitrate concentration, detected through Landsat-TM satellite images, the IDRISI program, and field data. The results indicated that through satellite images it is possible to recognize nitrate concentrations in soil layers up to 60-90 cm deep, where high nitrate concentrations are directly associated to soil lixiviation and cause problems of pollution. When alfalfa is used as nitrate indicator, the satellite image shows nitrate concentrations with 91.88 % certainty; in the case of corn, the image only presents 63.33 % certainty.

Mexico, like the rest of the world, needs to make an inventory of their forest resources in order to plan and execute forest management programs in a timely and appropriate way. A method for the obtaining this type of information is through prediction models. This study was conducted to evaluate the ability of the artificial neuronal networks (ANN) to predict types of forest coverings. The ANN was based on geographic information (altitude, aspect, slope, distances to the rivers, geology and edafology) and satellite images transformed with a principal components analysis (ACP1, ACP2 and ACP3), to define the dependent variable (vegetation). This information was processed with a back-propagation ANN with two hidden layers, with its respective activation functions (tangential hyperbolic and Gaussian). An r2=0.8617 for the phase of training and r2=0.8514 in the test phase were obtained, achieving 83% correctly predicted sites. This exceeds values reached by other authors using traditional methods.

In this paper we review the origin, distribution, botany, diversity, ecology, cultivation, production, economic importance, problems and perspectives of the integral management of the coconut palm. Also, aspects such as the copra and “tuba” in Mexico, as well as case studies of the coast of Michoacán and Colima are considered from a botanical perspective. With this analysis we emphasize the importance of the coconut palm as a plant of multiple uses with an incalculable value in the tropical coast of Mexico.

Water saturated Persea americana wood samples of 20 x 20 x 10 mm were conditioned to 85, 65, 35, 0% relative humidity to determine their swelling and shrinking indexes as well as their main anisotropies. Another group of these wood samples was used to determine humidity desorption and sorption along the hygroscopic range of the wood. The dimensional change of Persea americana wood was from small to very small. Their service movement calculated from the linear swelling index (a) was 1.72 %, which is qualified as small. According to the drying shrinkage anisotropy (Abn = 2.67), it is considered that the biggest risk of possible distortion from moisture change could occur during drying from fiber saturation point to 12 % moisture content. Also, swelling anisotropy (Aq = 2.13) showed that the Persea americana wood can be considered moderately stable when its moisture content changes within the range of 18 to 8 %. Hysteresis values fluctuated from 0.788 to 0.885, with an average value of 0.834 for the relative humidity interval of 30 to 90 %.

The evaluation of timber resources of the wood has been indispensable for the development of management and forest use programs. For this reason, volumetric estimation of timber stocks has been a common practice for forest managers. The techniques and methodologies applied for this practice are very expensive and time-consuming. For this reason, alternative techniques have been sought that are more accurate and require less time for execution. This has been done through the implementation of statistic models and computer systems. This paper describes the creation and implementation of a computer program that validates 12 statistical models widely used in the construction of volumetric tables of species of pine timber in cold temperate climates. The program allowed selection of the model that best fits for the variables normal diameter and total height: the Modified Meyer model with Intercepted Origin (MMIO), which had the best fit for the variables normal diameter and total height with a coefficient of determination (R2) of 0.983 and a high correlation coefficient, as well as a mean square error of 0.0077. Finally, the program generates the table of timber volumes, using the mathematical model that is more precise in the calculation of the volume of the stand.

This research was conducted at the Eucaliptetum of the Universidad Autónoma Chapingo. The objective was to study the effect of fire on diameter growth of Eucalyptus camaldulensis Dehnh in forest plantations. A randomized complete block experimental design was used with three replications. The treatments were low intensity prescribed burn and control. The data were analyzed with analysis of covariance, using Proc Mixed of SAS®. The dependent variable was the annual increment in diameter with bark from 2000 to 2001. The covariate was the initial diameter. The annual increment in diameter was equal to 0.30 cm for the control, which exhibited statistically significant differences (p=0.0492) when compared with the prescribed burning treatment, where this variable had a value of 0.48 cm.

Based on 24 permanent sampling plots, randomly established in the Cupressus lusitanica Mill seedling production area, at the forest nursery in Technological Institute of Costa Rica, at Cartago, the present study was conducted during 28 weeks to determine a quality control methodology for this tree species in nurseries. A random sampling method is proposed based on random plots of two rows (28 seedlings), in which 11 quantitative and qualitative variables are recorded for each seedling sampled. The results showed 1.87 % bifurcated seedlings, 0.51 % with loss of meristem, 2.21 % with severely twisted stem, 15 % in suppressed sociological position, 0.68 % with mechanical injuries, 0.51 % with severe phytopathological problems, 13.5 % with low quality roots, and finally, 3.92 % of the seedlings were grade 3, or in the rejection category. Root length increased an average of 1.39 cm/week, stem diameter 1.14 mm/week, and total height 1.3 cm/week. Mortality rate was stabilized between the 12th and 15th week after transplanting and reached an accumulative percentage of nearly 25 %. Management and genetic (hereditary) are discussed as possible causes of the quality of cypress seedlings in nurseries. Finally, values of acceptability and rejection are proposed for cypress seedling production, based on the most important variables.

The main function of any wood finish for outdoors is to protect the wood surface from weathering processes, as well as to maintain its appearance. Weathering brings about surface deterioration, and therefore, it directly affects finish performance. The objective of this study was to determine the finish service life of two commercial polyurethane varnishes for outdoors (Polyform® 11000 and 7000) on alder (Alnus firmifolia Fernald), pine (Pinus patula Schl. et Cham.) and oak (Quercus insignis Mart. et Gal.) by means of accelerated weathering on a CTBA degradation wheel. Failure data in appearance and in adhesion were fitted to a Weibull accumulative distribution to estimate the finish service life. According to the obtained results, service life on alder, pine and oak wood was 5.0, 5.2 and 5.0 years, respectively, for varnish 11000, and 3.7, 3.4 and 4.9 years, respectively, for varnish 7000.