Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

In order to determine the level of inter and intraspecific variation in height growth rate and number of growth cycles, an 18months old experimental plantation established at Patoltecoya, Puebla was evaluated during a 12-month period. The plantation includes a total of 30 provenances of four Pinus species (10 of P. greggii Engelm., 11 of P. patula Schl. et Cham., 4 of P. tecunumanii (Schw.) Eguiluz et Perry and 5 of P. maximinoi H. E. Moore), in a split-plot random block experimental design on two adjacent sites. Both site and site*genotype interaction had no significant effect on growth variables, but species and provenances within species showed a significant variation (p≤ 0.01) in all variables. Variation among species was 2 to 6 times higher than within species, so there is a greater selection potential at the species level for all variables measured. Pinus maximinoi and P. tecunumanii showed the highest growth rate (2.50 and 2.44 m year-1 respectively) while P. patula presented the lowest growth rate (1.92 m year-1). Height growth was negatively correlated (r = -0.98) with the number of growth cycles in P. tecunumanii and positively correlated (r = 0.75) in P. patula, but no significant correlation was found between these traits in P. greggii and P. maximinoi. In addition, each species showed a particular geographic variation pattern in these growth traits.

The objectives of this work were: 1) to estimate parameters and 2) to validate 7 taper functions fitted to stem profiles of  5 commercial pine species of the El Salto, Durango region. Measurements of diameter at several stem heights were conducted in fallen trees during harvesting operations. The total number of trees measured for each species was: 507 (Pinus cooperi), 453 (P. durangensis), 424 (P. engelmannii), 400 (P. leiophylla), and 322 (P. herrerae) of which 75% were used to estimate parameters and the remaining 25% to test the goodness of fit of taper fuctions of Clutter (1980), Amidon (1984), Biging (1984), Kozak (1988), Kozak y Newnham (1992). Parameters were fitted by least square techniques in linear, polinomial and multiple regression analysis. The goodness of fit test consisted of comparing the statistics, coefficient of determination, standard error, and skewness, as well as, normality, randomness, and common variance of errors. The results showed that the model of Biging (1984) estimated better the stem profiles of the five pine species since it showed one of the largest coefficient of determination, one of the smallest standard errors and errors were distributed close to the normal. For this reason, this model is recommended to estimate stem profiles of the pine species of the study area. The model estimates accurately stem volume for trees with diameter smaller than 30 cm but it requires additional research to estimate merchanteable volume of trees with diameters larger than 30 cm.

The Argentinian Chaco is the most extensive phytogeographic region of the country. The forest resource is the principal source of wealth, and it is found in an alarming state of deterioration. The objective of this paper is to explain the growth as a function of age of Schinopsis quebracho-colorado (Schlecht.) Barkl. et Meyer, Anacardiaceae. Ten trees with DBH (diameter at breast height, 1.3 m) over 30 cm, from the natural forest of Los Pirpintos, Copo Department, Santiago del Estero, Argentina, were studied. The methodology adopted for the study is that of Helinska. Growth was determined by epidometric analysis.Growth rings are moderately boundary distinct (type 3 Coster). Average tree ring thickness is 2.19 mm (1.6 y 4.5). Ring thickness varies significatively with age and is not correlated with this variable. Growth rings have a maximum thickness at 61 years old.The evolution of shaft volume and the age are positive correlated, the same as the diameter, normal section and total height. The variables DBH, normal section area, total height, MIA, IA and age adjusted to second degree polynomial functions. Crown diameter/age, crown diameter/DBH, crown section/normal section area adjusted to logarithmic functions. DBH correlates positively with crown diameter and age. For the relationships of growth it is estimated a technological cut shift over 250 years.

The objective of this research was to characterize radial tracheid variation and to identify the climatic features that affect tracheid variation in Abies religiosa ( H.B.K. ) Schldtl. & Cham.. Twenty trees of Abies religiosa were selected in a population at sierra El Campanario in the state of Michoacan. Wood samples were removed at dbh (1.30 m) and prepared by the standard wood procedure. Four anatomical features of tracheids and ring width were analyzed. Tangential diameter of latewood tracheid and tangential lumen diameter of latewood tracheids, as well as tangential lumen diameter of earlywood tracheids show an increment from pith to vascular cambium. Latewood tracheid wall thickness has a strong increment near the pith, followed by amply fluctuations. Ring width possesses an inverse pattern than wall thickness. Regression analyses show that higher temperatures affect tracheid accumulation and size. These results suggest that maximum temperatures affect Abies religiosa cambial cells.

Over the last few years an intense and increasing deforestation has been gradually taking place. As a consequence, this phenomenon has brought about a notorious reduction in both Mexican and world wide forest areas. This problem has also appeared in the Yucatán Península, one of the regions in México where these ecosystems can be found, especially the tropical rain forest. This paper presents figures for the Mexican rain forest areas, as well as deforestation rates, particularly in the three states of the Yucatán Península (Campeche, Quintana Roo and Yucatán), from a national and international point of view. Deforestation causes are detailed. The fact is, however, that the results of the deforestation turn this problem into a national and overwhelming issue. Corrective actions that need to be put in place to address this problem include an efficient forest management plan that strives for the contribution of native dwellers that own the land and provide an excellent resource of traditional  knowledge. This knowledge needs to be part of the current foresttechniques that are used in the national gavernmental programs of forest management.

Tree species and their relative importance were analyzed in terms of basal area per hectare in 235 sites of 500 m2 each, on three small watersheds of the Sierra Madre Occidental, Durango, México. Sixty-eight percent of the sites had 3 to 5 species, although species number ranged from 1 to 9. The two most common species at each site, Pinus teocote and P. durangensis, accounted for 83% of the total basal area, indicating that these species can be used to phisonomically characterize the forest from this region. In 88.4% of the sites, the first species occupied half of the total basal area, the second species occupied half of the remaining basal area, and so forth until the last species. This pattern was described using a geometrical mathematical model that can be useful to manage forest stands. Main species and plant associations were also described.

The available information on species used for live fences in Veracruz is insufficient.  Because of this, the objective of this study was to produce an inventory of the species generally used.  The study was based on field observations, interviews, collection of botanical material and consulting of herbarium vouchers, as well as the data base on floristic data for Veracruz. A list of 218  species of vascular plants was obtained as a result of this study.  This is presented in alphabetical order of families. Common names, vegetation types and uses are also included.  It is important to stress that 88% of the species reported present diverse categories of additional use: 62 species were reported as edible; 55 as medicinal; 45 as ornamental; 36 as fuel; 27 used in rural construction; 22 as timber; 13 as fodder; 6 for honey production and 42 assigned to other categories of use. The use of native species within this agroforestry practice as a contribution to the adequate use of the flora and local germoplasm conservation has been emphasized.

This paper offers an outlook of the forest industry of Chihuahua, taking into account its development over the last three decades; for this purpose it is considered, for comparative ends, its strongest competitor, that of Durango state, and the place that both occupy in the national context. Statistical data are presented in regards to  the forest surface and the data on  wood stocks.The state forest production has being experiencing yearly decrements. With respect to the national context, the farming and animal husbandry, forestry and fishery sector of Chihuahua has an outstanding support of  the Gross Domestic Product (GDP). This presence is stronger if it is considered  that the wood and wood based industry provided 15% of the GDP of the manufacturer industry. In terms of the number of established industries, in the last decade, this number keeps stable.The main problems that the state forestry industry face are presented, along with some measures that the goverment and the private sector are taking in order to offset the negative impact of the commercial globalization and the technological lag that this sector currently show.

In this paper a review about the current use of bamboo use Mexico is presented along with the prospects of this material in the construction industry mainly. A bibliographic review of bamboo in the world and Mexico was made, and some interesting points that increase its potential for several aplications were found. Their extraordinary growth which could be about 5-6 years to reach a mature state, as oppsed to most wood species, which takes about four times as much, heightens the interest in this plant. In regards to the mechanical and physical properties, bamboo has advantages over several wood species which are used regularly in building construction.

An analysis about the status of the wood industry in the state of Veracruz, México is done, simultaneously, it is assessed that established in the states of Puebla, México, Tlaxcala and Hidalgo. For the objectives of this paper, these states are considered to be grouped in the mid-west region. Also, to outline the situation of Veracruz in the national context, it is compared with the most important states regarding wood production, which are: Durango, Chihuahua and Michoacán. The relationship with the midwest region is that, because of geographical reasons, the region becomes the natural market for Veracruz forest products. The analysis was based in a survey applied by the Secretary of the Environment, Natural Resources and Fisheries, to the national forest industry, during September-December 1995. This diagnostic includes: number of industries, municipalities in which they are located, type of ownership, industrial capacity and its current state of use and type of industry. The industry potential is assessed, taking into account the forest land and the volume that could be exploited per state and for the region. For the state of Veracruz the level of wood prices are given, comparing them with the national average, and taking into account the sale point: standing, in the road and in the yard. Survey’s results point out that, the sawing industry prevails; the average industry works at 39% of its capacity. Since the 50's, wood industry production in Veracruz has been falling and its industrial capacity is underutilized. The situation could be partially explained by the conversion of forestlands to agricultural uses, mainly for cattle ranching.