Search

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the last 20 years in Mexico, 30 % of the plantations supported by the Comisión Nacional Forestal (National Forestry Commission, CONAFOR) were made for timber purposes and established in the states of Tabasco, Veracruz, and Campeche, in Mexico. The economic valuation and management of plantations for these purposes are optimized by estimating the timber volume by type of product. The objectives of this study were to fit three compatible systems of segmented equations of taper and merchantable outside-bark volume; identify functions of taper and cumulative volume of heartwood; and analyze the dendrometric types based on the system developed by Fang et al. (2000) for plantations of clonal trees of Acacia mangium Willd., located in Huimanguillo, Tabasco, Mexico. Ninety-one (91) trees (2, 3, 7 and 8 years old) were cut down and two data groups were formed: 60 trees for fitting, and 31 for validation. The stem volume per section was calculated using the overlapping bolts method. The selection of the models was made according to the classification of four goodness-of-fit statistics. The system developed by Fang et al. (2000) showed reasonable estimates with both groups of measurements. The heartwood volume function overestimated the average percentage of heartwood relative to the inside bark volume in 2-yearold trees. However, it estimated them logically for the other ages: 34.7 % at 3 years, 61.8 % at 7 years, and 67 % at 8 years. The ratio heartwood taper to inside bark taper decreased after reaching 70 % of height. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reproduction by seed promotes genetic diversity in maguey (Agave salmiana), and if fertilization is adequate, it can increase growth. In pulque maguey, although reproduction by seed is not a common practice, its study is necessary. For this reason, the objectives of this study were 1) to evaluate the effect of organic and chemical fertilization on growth and 2) to determine the CO2 exchange rate (CER) in two conditions of soil moisture in three variants of A. salmiana (subsp. crassispina, var. salmiana and var. ferox) obtained from seed in San Bartolomé Actopan, municipality of Temascalapa, State of Mexico. The hypothesis was that plants treated with chemical fertilizer will have greater growth than those treated with organic fertilizer and the control, and plants fertilized with organic and chemical fertilizer will have a higher CER in two conditions of soil moisture. The experimental design was completely randomized with n=11 for growth variables, n=3 for nutrient content and CO2 exchange rate. Growth was measured every month in 2.9- to 3.6-yearold plants, and CO2 exchange rate was measured in 3.6-yearold plants with irrigation and in 3.75-year-old plants under water stress. Organic fertilizer from pig manure favored plant height and diameter and number of leaves. The subespecies crassispina had the highest values of the evaluated variables, and A. salmiana var. salmiana cultivated with chemical fertilization was outstanding for the number of shoots emitted. The highest CO2 exchange rate occurred between 22:00 and 02:00 h and was higher in plants with abundant soil moisture (irrigated) than in plants with moisture below permanent wilting point. In the latter condition, the plants grown with organic and chemical fertilizer assimilated 60% more CO2 than the control. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taper, or stem profile functions are practical mathematical tools for quantifying the volume and distribution of products of standing trees. These data are relevant in creating forest management programs for timber production. The objective of this study was to fit different models of total volume, segmented taper functions compatible with merchantable volume, models of total volume within the compatible segmented taper-volume function of Fang, and to analyze the different dendrometric types in the segmented function of Fang. All this to obtain the best volume system for Pinus chiapensis in a commercial forest plantation in Tlatlauquitepec, Puebla, Mexico. Data from 35 felled trees, 3, 5, 6 and 7 years old were evaluated and a total of 485 pairs of observations of diameters and heights along the stem were generated. To calculate stem volume, the overlapping bolts method was used. The segmented functions of Fang, Max and Burkhart showed better precision, evidenced by higher coefficients of determination and lower values in the mean square root of the error, coefficient of variation and average absolute bias. The segmented Fang function suggests two inflexion points. The first occurred at 5% and indicated a geometric change from neiloid to paraboloid, and the second occurred at 50% of the total height, indicating the geometric change from paraboloid to cone. The model of the combined fitted variable in the Fang system denotes a mean form factor of 0.39, closer to a cone than to a paraboloid. The statistical results indicated that the Fang compatible system combined with the Takata total volume model allow precise prediction of taper and of total and merchantable volume. [ABSTRACT FROM AUTHOR]

Copyright of Agrociencia is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agrociencia is the property of Colegio de Postgraduados and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A Timber Growth and Yield System (TGYS) is a set of models that quantitatively describe the growth and yield of forest stands over time. The aim of this study is to build a TGYS as a support tool for decision-making in the management of Pinus chiapensis (Martínez) Andresen. Data were collected from 44 plots established in 2013 at Tlatlauquitepec, Puebla, Mexico, and measured again in 2014. The components of the system were generated by the algebraic difference approach. The fitting was done with the seemingly unrelated regression technique (SUR) as a system of simultaneous equations. For the dominant height, Hossfeld IV polymorphic model was the most appropriate. Models for the basal area, number of trees and volume explained between 80.9 % and 99.9 % of the total variation. The yield table indicates that in low productivity sites (site index of 10 m), the maximum current annual increment (CAI) in volume occurs at 14 years, with a potential volume of 25.18 m3 ha-1 and an average yield of 196.84 m3 ha-1. In sites of mean index (14 m), the maximum CAI in volume takes place at 11 years, which has a potential volume of 32.73 m3 ha-1 and an average yield of 199.21 m3 ha-1. In high productivity areas (18 m), maximum CAI takes place at 9 years, with a potential volume of 40.66 m3 ha-1 and yield of 200.97 m3 ha-1. The estimated volume rotation at these sites occurs at 17 years, with a yield of 472.39 m3 ha-1. On average sites, the absolute volume rotation occurs at 20 years with yields of 453.54 m3 ha-1. At low productivity sites, this rotation is close to 25 years with a yield of 441.64 m3 ha-1. [ABSTRACT FROM AUTHOR]

Plant parasitic nematodes are among the major phytosanitary problems affecting banana crops worldwide. In México, this fruit is one of the main agricultural products and in the state of Veracruz the most important production area is located in the Atzalan and Tlapacoyan municipalities. In some farms of these municipalities banana plants with lesions and galling of the root, symptoms caused by nematodes, have been detected. To determine which nematodes were associated with these symptoms, roots were collected in six plantations of Atzalan and Tlapacoyan municipalities in April 2014. Identification of nematodes was performed according to their morphological characteristics, and in the case of Meloidogyne species, specific molecular markers were used. The number of nematodes per 100 g root was also quantified. Helicotylenchus sp. Meloidogyne incognita, Meloidogyne arenaria, Criconema sp., Helicotylenchus multicinctus and Radopholus similis were detected involved in the affecting of root system. The last four are recorded for the first time in the Veracruz banana plantations. [ABSTRACT FROM AUTHOR]

Wild populations of Comadia redtenbacheri Hammerschmidt (Lepidoptera: Cossidae), known in its larval stage as the agave redworm, are gathered intensively for sale and consumption as food. To define adequate conditions for their pupation in confinement, the effect of handling larvae during collection, their weight when induced to pupate, substrate type and the moisture content provided during this stage of development, were evaluated over 2 consecutive yr. These factors were analyzed by logistic regression (PROC GENMOD, α = 0.05), relative to the emergence of adults. The relationship between larval weight and adult sexual gender was analyzed with a contingency table. The larvae exhibited adaptation to different substrates used for pupation, and substrates could be reused. The heavy clay content soil from areas where agaves grow, mixed with vermiculite (50:50), was the most suitable substrate (estimated value 0.7304). Moisture had no significant effect on pupation. Emergence of adults was significantly greater from larvae that had not been handled roughly as those acquired from commercial venders. According to the Chi-square test, the capacity to pupate by fifth instar larvae that weighed 0.30 to 0.39 g was not significantly different from that of the sixth and seventh instars that weighed 0.40 g or more. Males emerged mainly from cocoons produced by the smallest larvae, while females emerged mainly from cocoons by heavier larvae. [ABSTRACT FROM AUTHOR]