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

At the municipality of Iranduba, in the state of Amazonas, there is a high consumption of wood by the local communities, for both charcoal production and to burn for producing bricks. As a result, EMBRAPA has developed a project to grow trees at Iranduba’s communities. So, the goal of this study was to evaluate the species Acacia auriculiformis (exotic) and Ormosia paraensis (native) by dendrometric variables, basic density, heating power and immediate analysis, through an experiment at Estação Experimental da EMBRAPA, in Iranduba. The experimental design was by random blocks with three repetitions, in a total of six parcels with 25 plants each. Five trees were taken out of the nine middle trees of the useful area. Discs 5 cm thick were taken from those trees and turned into proof bodies in order to determine the basic density and other tests. Analysis of variance and Tuckey tests, at 5% probability, were performed. A. auriculiformis (23,61 cm -15,90 m) was larger than O. paraensis (7,26 cm-7,06m) in diameter and height, respectively. Both species presented medium density, but A. auriculiformis (0,63 g/cm3) had greater values than O. paraensis (0,55 g/cm3). The heating potential of A. auriculiformis (4383,65 kcal/kg) was statistically higher than that of O. paraensis (4381,24 kcal/kg). For the immediate analysis A. auriculiformis showed greater values than O. paraensis, but presented lower values for fixed carbon. The results of this study showed that both species can be grown and used as proposed. 

With the purpose of knowing the soil protection that tree crowns provide in a test of provenances of Pinus greggii Engelm. planted 4.5 years prior to the test in the Cerro El Potosí, Galeana, Nuevo León, survival, height and crown characteristics were measured; crown projection area, luminance interception area and percentage of crown were also calculated. No significant difference was found between provenances in the survival, but in general it was found a survival rate of 93%; however, there were significant differences (P≤0,05) in height, height at the first branch, height to the wide point of the crown, crown projection area, luminance interception area and percentage of crown. The trees of the provenances with greater crown projection area had 0,85 m2 and in the luminance interception area varied in more of 1,1 m2 between the provenances extremes. For the crown percentage the higher value obtained was of 89,1% of stems with crown. The components of variance showed that provenances provided 7.5% of the total variation in crown projection area and in the crown diameter. On the other hand, this value diminished for height at the first branch and height to the wide point of the crown with 5,2% and 2,9%, respectively. After 4,5 years of establishing the test, the crowns of trees have covered 14,8% of the total surface planted. The tree growth was positively correlated with the luminance interception area (r = 0,94), crown projection area (r = 0,86) and percentage of crown (r = 0,48). The study shows evidences to select the provenance of Los Lirios, Coahuila and Agua Fría, Nuevo León as the best choices to protect the soil at the planting site.

In the period from February through June 2004, the presence of different bird species was studied in two zones located at the Experimental Forest Station Zoquiapan (EFEZ for its Spanish acronym), state of Mexico, one with slightly disturbed pine forest (ZOQ 1) and another with mixed perturbed forest (ZOQ 2). The points recounting method with fixed radio for bird monitoring was used as well as the square embedded method and the quadrant with a central point, the last one to allow sampling the vegetation. The distribution of birds in vertical vegetation strata was characterized and compared using Poisson regression analysis and frequency observation; furthermore, a specific analysis was developed to describe the vegetal structure in both zones. The vertical distribution of birds followed four patterns: low (B), high (A), high-low (AB) and indeterminate (I). The individual’s abundance per stratum had a different value within strata and zones; in both sites the upper stratum showed a greater abundance than in the low and medium ones, although the number of individuals per specie registered in each stratum was the greatest in the perturbed mixed forest. The relative importance value (VIR for its Spanish acronym) of vegetation confirmed than ZOQ 1 had Pinus hartwegii as the predominant specie with some shrubs of Penstemon gentianoides and Senecio asteracae. ZOQ 2 was a mixed forest comprised by S. asteracae, P. gentianoides, Lupinus montanus shrubs and Alnus jorullensis, P. hartwegii and Abies religiosa trees. The height histograms determined two and three vertical strata, respectively.

Vinal (Prosopis ruscifolia) is a multi-purpose tree, halophyte, colonizer par excellence of unstable environments proved to flooding. The research objective of this work are: Analyseng the growth prospects of individual trees in relation to age, and estimate biological turn short. Fifteen trees of Prosopis ruscifolia, Mimosaceae, were selected from the natural forest of Loreto, San Martin Department, Santiago del Estero province, Argentina. Trees selection were based on the following criteria dominant canopy, healthy, with good form, more than 15 cm of DBH and free of defects. Transverse sections were obtained at different heights from 0,30, 1,30 m, and until the first branching. Growths rings were determined in four radii at north, south, east and west orientations. Rings width was measured with the Computerized Equipment ANIOL and the program CATRAS. Prosopis ruscifolia is a rapid growth tree in the Semi arid Chaco region, with ring average thickness of 5,66 mm (2,20-9,8). Minimum cut diameter is 25 cm, which is equivalent to 23 years. IMA and AI calculated by volume of stem reache the biological cut shift at the age of 45 years. The behaviour of this species in other growing conditions requires further study.

Traditionally, the forest capacity to produce multiple goods and services has been overlooked in favor of developing alternatives that maximize timber production or economic profit alone. This approach is suboptimal, it fails to address ecosystem interactions, and occasionally leads to degradation of some of its components. In this study, a technical framework to analyze and solve a multiobjective forest problem in an ejido of Durango, Mexico is presented. Forest inventory data and expert consultation were used to construct ten objective response functions expressed in terms of tree basal area, number of trees per hectare, and quadratic mean diameter. Compromise programming, a multiobjective decision-making technique was used to determine the most preferred solution of forest structures. Forest vegetation simulator and geographical information systems were used in order to evaluate the solutions for various clusters. The simulated optimal forest structures were typically above current stand conditions. These differences can be due to past management practices and other forest disturbances that reduced stocking and quality of residual trees. The use of this type of multiobjective decision making approach can help understand forest stand dynamics and long-term management of forest goods and services. 

An anatomical, physical and physiological study of the heartwood and sapwood of Gliricidia sepium ( Jacq.) Steud. was carried out using six trees collected during the rainy and dry seasons in a dry forest from Veracruz, México. Stem segments were cut at 1,30 m above the ground for obtaining wood samples for macroscopic and microscopic observations, and for the water content and specific gravity analyses. Following classical microtechnique procedures and international classifications and nomenclatures for describing microscopic features, wood samples and permanent slides of wood sections and dissociated material were made. Estimations of vulnerability and collapse indexes, and K h-theoretical were made from vessel diameter, vessel number and effective vessel area. Analysis of variance and principal components analysis showed that some fiber, vessels, rays and pit features influenced differences among trees, sites and seasons. Although variability of those features is relatively low, it would explain the sapwood and heartwood stability during changes in the hydric regime caused by dryness and rain. Collapse and mvulnerability indexes, as well as K esomorphic xylem quite vulnerable h show ato embolisms, but with high success to develop in disturbed environments. This could be explained by the presence of tyloses, abundant axial parenchyma and high values of specific gravity that assure resistance of fiber and vessel cell walls to collapse.

Pinus durangensis is the most utilized and abundant tree species in the Guachochi region of the state of Chihuahua; however, there is a lack of appropriate knowledge to get accurate volume estimations. Therefore, the purpose of this study was to model the tapering of the bole to allow developing an equation to predict merchantable and total volume, which guarantees its operative application. For this purpose, a trigonometric model was fitted to 4 502 data pairs of 663 trees felled during harvesting operations. The goodness of fit test consisted of comparing the statistics, coefficient of determination, root mean square error, and a precision index. Model fitting includes the use of appropriate statistical procedures to account for the problems of autocorrelation and heterocedasticity associated with the development of taper equations. The model gave best results in terms of predictive capacity, and via mathematic integration, an equation for tapering was obtained which is compatible with the merchantable and the total volume. It was concluded that the generated equations have a solid statistical foundation, and therefore constitute an essential tool for improving accuracy in forestry inventories, assuring its usage not only in the study region but its application is recommended also in other sites, with the necessary adaptation of the model to the respective local conditions.

In the mountain range of Álvarez, San Luis Potosí eighteen oak species have been identified; two of them (Quercus sebifera and Q. tinkhami) included into the Quercus section or white oaks are shrubs. Currently, studies are not known on the wood characteristics of these species, which are only used locally in a reduced and rudimentary way.  Their chemical composition is presented here. Essays to estimate relative content (%) of lignin, extracts and ashes were carried out; specific gravity was also calculated along with volume of cellulose. Basic statistics were estimated for each parameter obtained. Variance analyses were applied between the essays sets of cellulose, lignin, ash, and extracts. Not significant differences (p > 95%) were found between species for cellulose and lignin. These results were similar to those presented by other authors for Mexican oaks. Ash volume resulted to be greater; it may be due to their particular climate and soil type, mainly. The extracts of Q. sebifera obtained by the ethanol-benzene mixture and by hot water were greater than those published for white oaks. These species were different (p > 95%) for extract content. Ash and extracts richness of these species seems to be related to their aridity adaptations. Relative basic density values for Q. sebifera were medium and high for Q. tinkhami.

The recovery of standing Pinus stock after a harvest in forests treated under irregular and regular forest management systems was evaluated. The management history of five forest properties managed under the Mexican Management Method of Irregular Forests (MMOBI) and twelve under the Silvicultural Development Method (MDS) during the period 1995-96 was analyzed. In addition, in 2004 within these forest properties, 12 basic MMOBI forest management units and 34 basic MDS units were sampled with an intensity of 5 % of their total area, using 1000 m2 circular plots. Of the 17 properties managed, either with MMOBI or MDS in 1995-96, 11 had shifted to another forest planning method by the year 2004. In eight of the 17 properties, management programs for the harvest cycle following the one containing the data for the period 199596 indicated that there were modifications to the delimitation of the basic forest management units. It was found out that by 2004, even though a cutting cycle had almost culminated, the volume per hectare in six of the 12 MMOBI units analyzed and in 19 of the 34 MDS units analyzed were significantly different (5     α= %). The differences are attributed to the changes in delimitation of the basic forest management units and to a low precision of the forest inventories, due to: a) inadequate sampling intensity, b) errors in the estimation of diameters and heights classes, and c) the use of inadequate basal area factors.

The importance of Non Timber Forest Products (NTFP) has increased along with growing concern on deforestation, and the need to diversify and increase the value of forest resources. The NTFP include a number of products which are important in the daily life of local communities, because they contribute to obtain additional earnings and employment. In the present investigation, the available NTFP information for Mexico is reviewed, in order to identify production patterns, and to contribute to generate sustainable management proposals. According to governmental sources, in Mexico there are 20 000 plant species, 950 of them provide NTFP, but only 10% of this last figure has commercial value and is subjected to regulation. Currently, NFTP are classified in seven categories. In the period 1985-2003, NFTP mean annual production was 135 667,158 tons. The category “other products” was the most important, followed by “resins”, “fibres”, “waxes”, “gums” and “rhizomes”. During this period, the production of “resins” tended to be stable, “fibres” and “waxes” tended to decline, but “gums” and “rhizomes” fall down. In 2003, the NFTP national value was $498 098,712 pesos. The categories “other products” and “resins” accounted for 68,9% and 22,5%, respectively of total value. In contrast, “forest soil” (used for gardens) represented 62,3% of  production in tons, but accounted only for 2,63% of the total PFNM value. It is concluded that NTFP official information is scanty and incomplete. Because of this, it is necessary to develop a new classification, especially to divide “other products”, since it includes a number of important products not properly quantified, such as medicinal plants.