Victoria de Durango, Mexico

Institute of Technology Falls

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Fierros-Mateo R.,Colegio de Mexico | De los Santos-Posadas H.M.,Colegio de Mexico | Fierros-Gonzalez M.A.,Colegio de Mexico | Cruz-Cobos F.,Institute of Technology Falls
Agrociencia | Year: 2017

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 m3ha-1.


Vargas-Larreta B.,Institute of Technology Falls | Lopez-Sanchez C.A.,Universidad Juárez del Estado de Durango | Corral-Rivas J.J.,Universidad Juárez del Estado de Durango | Lopez-Martinez J.O.,Colegio de Mexico | And 2 more authors.
Forests | Year: 2017

This paper presents new equations for estimating above-ground biomass (AGB) and biomass components of seventeen forest species in the temperate forests of northwestern Mexico. A data set corresponding to 1336 destructively sampled oak and pine trees was used to fit the models. The generalized method of moments was used to simultaneously fit systems of equations for biomass components and AGB, to ensure additivity. In addition, the carbon content of each tree component was calculated by the dry combustion method, in a TOC analyser. The results of crossvalidation indicated that the fitted equations accounted for on average 91%, 82%, 83% and 76% of the observed variance in stem wood and stem bark, branch and foliage biomass, respectively, whereas the total AGB equations explained on average 93% of the total observed variance in AGB. The inclusion of total height (h) or diameter at breast height2 × total height (d2h) as a predictor in the d-only based equations systems slightly improved estimates for stem wood, stem bark and total above-ground biomass, and greatly improved the estimates produced by the branch and foliage biomass equations. The predictive power of the proposed equations is higher than that of existing models for the study area. The fitted equations were used to estimate stand level AGB stocks from data on growing stock in 429 permanent sampling plots. Three machine-learning techniques were used to model the estimated stand level AGB and carbon contents; the selected models were used to map the AGB and carbon distributions in the study area, for which mean values of respectively 129.84 Mg ha-1 and 63.80 Mg ha-1 were obtained. © 2017 by the authors.


Cabral-Aleman C.,Institute of Technology Falls | Pompa-Garcia M.,Universidad Juárez del Estado de Durango | Acosta-Hernandez A.C.,Universidad Juárez del Estado de Durango | Zuniga-Vasquez J.M.,Universidad Juárez del Estado de Durango | Camarero J.J.,CSIC - Pyrenean Institute of Ecology
Forests | Year: 2017

The existence of endangered tree species in Mexico necessitates an understanding of their vulnerability to the predicted climate changes (warming and drying trends). In this study, the sensitivity to climate of earlywood (EW) and latewood (LW) widths of the threatened Picea chihuahuana was determined. The response of EW and LW to climate variables (maximum temperature, minimum temperature, precipitation, evaporation, and a drought index) was analyzed by means of correlation analysis using dendrochronology over the period of 1950-2015. EW and LW production were enhanced by cool and wet conditions during winter prior to the start of growing season. During the growing season, EW and LW production increased in response to cool spring and summer conditions, respectively; temperatures and year-round evaporation, excluding summer and the previous drought in the period prior to the growing season. EW was sensitive to seasonal drought, which is a concern considering the predicted aridification trends for the study area. These results provide further knowledge on the dendroecological potential of Picea chihuahuana. © 2017 by the authors.


Lopez-Sanchez C.A.,Universidad Juárez del Estado de Durango | Rodriguez-Soalleiro R.,University of Santiago de Compostela | Castedo-Dorado F.,University of León | Corral-Rivas S.,Institute of Technology Falls | Alvarez-Gonzalez J.G.,University of Santiago de Compostela
Southern Forests | Year: 2016

Five stem taper models belonging to three different taper function categories were fitted to data corresponding to 282 Pseudotsuga menziesii trees. The trees were selected in the area surrounding 61 research plots installed in Galicia, Asturias and the Basque Country, northern Spain. The models were simultaneously fitted to observed values of diameter outside bark and inside bark. A third-order continuous-time autoregressive error structure was used to account for autocorrelation. Selection of the best model was based on both numerical (goodness-of-fit statistics) and graphical analysis (plots of residuals against position along the stem and against tree size). The three-segmented taper model finally selected has the advantage of being compatible with both a merchantable and a total stem volume equation. © 2016 NISC (Pty) Ltd


Crecente-Campo F.,Instituto Nacional Of Investigacion Y Tecnologia Agraria Y Alimentaria Inia | Corral-Rivas J.J.,Universidad Juárez del Estado de Durango | Vargas-Larreta B.,Institute of Technology Falls | Wehenkel C.,Universidad Juárez del Estado de Durango
Annals of Forest Science | Year: 2014

• Context: Tree height prediction is an important issue in forest management since tree heights are usually measured only in a sample of trees. Although numerous model approaches have been used for this purpose, no agreement on which one is more appropriate has been achieved. • Aims: To analyse the random effects of basic and generalised height-diameter (h-d) models fitted to multi-species uneven-aged forest stands, and to establish their ability to explain differences between ecoregions, plots and species. • Methods: Height and diameter measurements for 29,084 trees from 187 sample plots located in the state of Durango (Mexico) were used. Basic and generalised h-d models were fitted in a mixed-models framework. The variability between ecoregions, plots and species was considered in the random effects definition. Model calibration for different height sampling designs and sampling sizes was also analysed. • Results: Random components performed well in explaining the differences in the h-d relationship between the different plots and species; however, no significant variance for the random effects was found for the different ecoregions. A calibrated basic h-d model produced similar results to a fixed-effects generalised h-d model when a sufficiently large number of trees was used in the calibration process. • Conclusion: From a practical point of view, if no calibration is carried out, different models should be used for the different species, so that at least the variation among species is captured. © 2013 INRA and Springer-Verlag France.


Corral-Rivas J.J.,Universidad Juárez del Estado de Durango | Wehenkel C.,Universidad Juárez del Estado de Durango | Castellanos-Bocaz H.A.,Universidad Juárez del Estado de Durango | Vargas-Larreta B.,Institute of Technology Falls | Dieguez-Aranda U.,University of Santiago de Compostela
Journal of Forest Research | Year: 2010

The ability to precisely describe forest spatial structures, and their modifications through timber harvesting, is of prime importance for sustainable management of complex forest ecosystems, especially regarding uneven-aged, multi-species forests. For this purpose, forest managers require statistical indices that are meaningful descriptors of the spatial structure of a given forest ecosystem. This paper presents a new sensitive permutation test of spatial randomness for solving the classification problem of three nearest neighbour-based indices. The test enables a categorisation of a spatial pattern as a whole into one of three groups: regular, random or cluster, with a sensitivity comparable to that of Ripley's L test, at finer scales. The examples illustrate how the Clark and Evans, the uniform angle, and the mean directional indices can be used for precise detection of departure from spatial randomness. The results show that these three indices should be used simultaneously because they are sensitive to slightly different types of processes. © 2010 The Japanese Forest Society and Springer.


Mendez-Gonzalez J.,Antonio Narro Agrarian Autonomous University | Luckie-Navarrete S.L.,Antonio Narro Agrarian Autonomous University | Capo-Arteaga M.A.,Antonio Narro Agrarian Autonomous University | Najera-Luna J.A.,Institute of Technology Falls
Agrociencia | Year: 2011

The generation of equations of biomass is important because they allow to evaluate the structure and condition of a forest, quantify its productivity, determine the amount of fixed carbon, the fixation rate of CO 2, and thus valuate the impact on the mitigation of greenhouse gases. The objective of the present study was to fit allometric equations to quantify the accumulation of biomass (B), carbon (C), and carbon equivalent (CO 2e) in a mixed plantation of 12 years of age of Pinus devoniana Lindl. and Pinus pseudostrobus Lindl., in Jerécuaro, state of Guanajuato, México. The biomass of each tree, leaves plus branches (Bhr), stem (Bf) and total (Bt) was calculated using the ratio between dry weight and fresh weight, in 20 trees of each species. Through stem analyses and the Schumacher model the rate of annual increment of B, C and CO 2e was obtained. Results indicate that the allometric equations efficiently quantify the components of biomass, especially of Bf (R 2>0.85) in P. pseudostrobus, this species showing the highest increments in aboveground biomass. The total aboveground biomass, of 60.2 and 58.4 % was registered in the stem; 39.8 and 41.6 % in the leaves and branches of P. devoniana and P. pseudostrobus. Values calculated were 39.36 t B ha -1, 19.68 t C ha -1 and 72.02 t CO 2e ha -1, after 12 years of the establishment of the plantation. According to the Schumacher model, the maximum productivity of aboveground biomass (Bf and Bhr) is reached at 20 years of age, which represents 3.96, 1.98 and 7.27 t ha -1 year -1 of B, C and CO 2e.


Najera-Luna J.A.,Institute of Technology Falls | Sanchez-Medrano J.A.,Institute of Technology Falls | Mendez-Gonzalez J.,Antonio Narro Agrarian Autonomous University
Forest Systems | Year: 2013

Aim of study: Evaluate times and yields in the transformation of pine logs to pieces of pallets. Area of study: Four sawmills of the forest region of El Salto, Durango, Mexico. Material and methods: The sample size was 388 logs with 32.91 m3 as volume without bark grouped in four diameter classes and five taper classes. The transformation time was estimated using the "Snap-back timing" method, and yield was defined as the ratio between pallets and log volume. Main results: The time required to obtain 1,000 bft of pallets is approximately 5.8 hours and the mean yield is 56%. This means that for each cubic meter of logs without bark, it is possible to obtain 240 board feet of pallets (bft). In addition, 4.16 m3 of logs without bark are required to obtain 1000 board feet of pallets. The estimated mean productivity was 0.54 m3/h. Research highlights: As the log diameter increases, yield also increases. The taper of the logs was not significant in the transformation yield.


Diaz-Ramirez B.,Institute of Technology Falls | Villanueva-Diaz J.,Inifap Cenid Raspa | Cerano-Paredes J.,Inifap Cenid Raspa
Madera Bosques | Year: 2016

The Presidio San Pedro basin yields the water of one the main streams draining to Marismas Nacionales in the states of Sinaloa and Nayarit. A dominant conifer species on this watershed is Pinus durangensis a heavily logged species such that old-growth forest has disappeared. Increment cores from 63 trees of P. durangensis in a low disturbed site were extracted to analyze its dendrochronological potential. The samples were processed by standard dendrochronological techniques. Series intercorrelation (0.463), mean sensitivity (0.309), first order autocorrelation (0.41), and signal to- noise ratio (5.24) among other parameters indicated excellent potential of the species for dendrochronological purposes. Time series of earlywood, latewood and total ring width were developed with a length of 232 years (1780-2012). The earlywood chronology responded to the accumulated January-August precipitation from four weather stations in the watershed and a linear regression model was used to reconstruct seasonal winter to early summer precipitation. Similar to other previous climatic reconstructions for the Presidio San Pedro basin, ENSO was the most influential phenomena on explaining the interannual and multiannual variability. It was not found a significant relationship between latewood indices and summer precipitation indicating low inter-annual variability of the North American Monsoon System, even though this phenomenon causes over 70% of the annual precipitation on this region. © 2016, Instituto de Ecologia. All rights reserved.


PubMed | Institute of Technology Falls
Type: Journal Article | Journal: Behavior analysis in practice | Year: 2016

I comment on Horners and Sugais article regarding the lessons learned from implementing Positive Behavioral Interventions and Support (PBIS)-that is, the things to consider when attempting to extend other works in behavior analysis to the likes of mainstream society. In adopting a critical eye toward the PBIS model, I comment first on the need for dissemination of behavioral principles to a public audience, and then outline the suggestions made by the authors for enhancing acceptance across disciplines. I clarify the definition of PBIS presented by the authors, and summarize the benefits and drawbacks associated with the conceptual argument surrounding the contention that PBIS is a behavior analytic approach to system-wide change, and argue instead for the distinction of elements in the PBIS model and their respective empirical effectiveness. I refer to other works in behavior analysis that are relevant to the current discussion and offer additional considerations for behavior analysts interested in forging ahead with endeavors that aim increase dissemination, particularly those that incorporate a culmination of alternative professional practices.

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