Victoria de Durango, Mexico

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Corral-Rivas S.,Institute of Technology Falls | Alvarez-Gonzalez J.G.,University of Santiago de Compostela | Corral-Rivas J.J.,Universidad Juárez del Estado de Durango | Lopez-Sanchez C.A.,Universidad Juárez del Estado de Durango
Revista Chapingo, Serie Ciencias Forestales y del Ambiente | Year: 2015

The diameter distribution of 44 permanent plots (conifers and broadleaf trees) was modeled using the three-parameter Weibull and Johnson's SB probability density functions (PDFs) in Santiago Papasquiaro, Durango. Four different methods of fitting parameters were used: maximum likelihood (ML), moments (MM), non-linear regression by ordinary least squares (ONLS) and percentiles (MP). The best method of fitting parameters for conifers and broadleaf trees was the method of moments. In modeling the Weibull PDFs, it was assumed that the location parameter (ε) corresponds to the minimum measurable diameter. The scale parameter (λ) was modeled using the method of prediction parameter (PPM) through a linear regression relating to the quadratic mean diameter and dominant height of the stand. Finally, the shape parameter (γ) was indirectly recovered by the method of moments through prediction of the average diameter of the stand. According to the Kolmogorov-Smirnov test (P= 0.05), 71 % of the plots for the group of conifers and 68 % of the plots for the group of broadleaf species come from a population that follows the fitting distribution function.

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.

Wehenkel C.,Universidad Juárez del Estado de Durango | Cruz-Cobos F.,Institute of Technology Falls | Carrillo A.,Autonomous University of Nuevo León | Lujan-Soto J.E.,Institute of Technology Falls
Scandinavian Journal of Forest Research | Year: 2012

The Sierra Madre Occidental ecoregion accommodates some of the richest biodiversity anywhere in North America and contains about two-thirds of the standing timber biomass in Mexico. Worldwide forest trees provide an industrial output of about 363 million cubic meters, with the volume of bark accounting for an estimated 10% of total tree volume, so that bark is a very important nonwoody product. In this study, the proportion of bark volume (PBV) and its correlation with selected tree characteristics as well as the relationship between total tree volume and wood volume (WV) and total volume and bark volume (BV) were calculated for the first time for the 16 common and commercially most important tree species in the temperate pine-oak forest region of El Salto (Durango) on the Sierra Madre Occidental, Mexico. Measurements were made on 2,027 felled trees. The PBV in the species investigated ranges from 0.129 to 0.260 depending on the species and genus, with a mean value of 0.175. BV and WV can be accurately estimated. The approach used in this study is simple and effective, and very user-friendly. The method is recommended for researchers wishing to develop bark models for other tree species. © 2012 Copyright Taylor and Francis Group, LLC.

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.

Rodriguez-Carrillo A.,Institute of Technology Falls | Cruz-Cobos F.,Institute of Technology Falls | Vargas-Larreta B.,Institute of Technology Falls | Hernandez F.J.,Institute of Technology Falls
Revista Chapingo, Serie Ciencias Forestales y del Ambiente | Year: 2015

The aim of this study was to determine the site quality of juniper (Juniperus deppeana Steud.) in the San Dimas region of the state of Durango, Mexico, using the site index method. The database comes from stem analysis of 43 trees felled in harvesting activities. The Chapman-Richards and Schumacher models, by means of the algebraic difference and generalized algebraic difference approaches, were tested to determine the site index; in addition, the error structure was modeled with a second-order autoregressive model to remedy the dependency of existing longitudinal errors. The results showed that the Chapman-Richards model in generalized algebraic difference form provided the best fit according to the adjusted coefficient of determination (R2 adj = 0.98) and root mean square error (RMSE = 0.46 m). Plotting of the quality curves generated with this model, superimposed on the observed heights, corroborated the goodness of fit of the model selected. The equation obtained with the generalized algebraic difference approach directly estimates the dominant height and site index at any height and base age.

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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