Abstract This study investigates the influence of incorporating 5% gray and white Portland cement on the electrical resistivity of wood–cement biocomposites manufactured from Pinus pseudostrobus sawdust and a wheat-protein adhesive. Three composite formulations were prepared: a control (no cement), gray-cement (MCgray), and white-cement (MCwhite) composites. Test specimens were fabricated under controlled thermal and humidity conditions and evaluated for density and electrical resistivity in transverse and parallel directions. Statistical analyses revealed that the addition of cement significantly affected both density and electrical resistivity. The density increased by approximately 7% for MCgray and 2.3% for MCwhite compared with the control. Electrical resistivity decreased markedly for both cement-containing composites: gray cement reduced resistivity by approximately 70%, while white cement achieved up to 75% reduction, with lower values in the parallel direction. These differences were attributed to the formation of conductive pathways associated with hydrated cement phases and ionic migration within the wheat-protein matrix. The results confirm that even low cement dosages of 5% substantially alter the microstructural compactness and conduction mechanisms of lignocellulosic composites. Notably, the comparable conductivity performance of white and gray cements suggests that oxide purity (Fe₂O₃ content) is not the only determining factor in electrical transport. This work provides at quantitative comparison of gray and white cements in wood-based biocomposites, contributing to the development of multifunctional, bio-based materials with tunable electrical properties.

In the propagation of plants in nurseries, it is important to define quality parameters to ensure their survival in the field. There is no evaluation of superior progenies in resin production in Michoacán, even though this economic activity is the most important in non-timber production. The objective was to generate plant quality parameters for dominant progenies at the site with resin production of Pinus pseudostrobus. In 2019, seed of 27 outstanding progenies in resin production was collected and five months after sowing they were transplanted into polyethylene bags and placed under the experimental design of random blocks with five repetitions, where the most vigorous individuals that represented the greatest number of individuals were included. potential. At 15 months after the transplant, the total height, basal diameter and biomass were evaluated, in addition, the slenderness indices, Dickson quality and lignification were calculated; intervals in plant quality indices or relationships were also determined. The analysis of variance and the Student-Newman-Keuls mean separation test show highly significant differences between the progenies (α = 0.01). The Llano 2 progeny is resistant to environmental effects, while Gómez 8 and Pascuala 9 have medium growth and more than 57.2 g biomass but are the most suitable for establishing plantations for resin production, given their morphological characteristics and plant quality indices. The plant quality indices generated and used in this study are easy to implement and interpret in forest nurseries for the identification of quality plants.

The Mixteca Oaxaqueña region has historically suffered from soil and vegetation loss. However, since the last decade of the previous century, successful reforestation efforts have been carried out in many areas. As a result, there is now a need to select phenotypes with superior growth and good wood quality. This study aimed to estimate genetic parameters and identify superior families of Apulco pine (Pinus pseudostrobus var. apulcensis (Lindl.) Shaw) based on growth and stem quality traits. After four years, growth and stem quality traits were evaluated in 64 open-pollinated families. Different selection intensities were tested using two evaluation methods. All traits showed significant differences among families (p ≤ 0.0016), with genetic coefficients of variation ranging from 8.01% to 18.84%. Heritability estimates for growth traits were high (hi2 = 0.42−0.66; hf2 = 0.55−0.63), whereas heritability for stem quality traits was slightly lower (hi2 = 0.01−0.38; hf2 = 0.01−0.38). Genetic correlations (rg) among growth traits were high and positive (rg ≥ 0.857), while correlations among stem quality traits and between quality and growth traits were more variable (r9 = −0.498 to 0.899). Based on both evaluation methods and a 25% selection intensity, sixteen superior families were identified, showing estimated genetic gains of approximately 4% for growth-related traits. These families are recommended for use in timber plantations, whereas a broader set is suggested for reforestation efforts in order to maintain genetic diversity.

Pinus and Quercus species face anthropogenic disturbances that affect their structure and distribution. Understanding the distribution patterns of these species is crucial for establishing appropriate management practices to conserve their diversity and the ecosystem services they provide. The aim of this study was to analyze pine and oak species’ distribution, dominance, and diversity patterns along an altitudinal gradient in the Monarch Butterfly Biosphere Reserve. We established 6 elevation transects (2,250 - 3,300 m asl) with 32 points every 150 m. At each site, 25 pine and oak trees located between 0 and 60 m from a central coordinate, with a diameter at breast height ≥ 10 cm, were recorded. Distribution patterns, dominance, and alpha and beta diversity were analyzed. The least abundant species were the most geographically restricted. Pinus pseudostrobus and Quercus laurina were the most dominant species. Alpha diversity was not associated with elevation, nor did it show a defined distribution pattern. Beta diversity was associated with elevation at the highest and lowest elevations, forming an inverted hump. These patterns may be the result of human activities, such as logging and agriculture, which have altered natural patterns of diversity and distribution.

The accurate estimation of tree volume and biomass is necessary for forest ecosystems management. However, traditional estimation methods are expensive, require a large amount of labor and materials, and may involve destructive sampling. In this study, a terrestrial laser scanner (TLS) and free software were used to estimate the volume and biomass of the stems of individual trees from two coniferous species, Abies religiosa (Kunth) Schltdl. & Cham and Pinus pseudostrobus Lindl, in the Monarch Butterfly Biosphere Reserve (MBBR), Michoacan, Mexico. TLS is an alternative to traditional measurement methods, which allows tree measurements to be extracted from a point cloud, opening up new opportunities to characterize the volume and biomass of standing trees. The simple linear regression analysis comparing stem volume and biomass estimates from different methods shows that the Vol_TLS and Vol_TModel relationship provides a better fit (R2 = 0.97, RMSE = 0.351 m3) compared to the Vol_TLS and Vol_OModel relationship (R2 = 0.93, RMSE = 0.537 m3). However, comparisons between measurements with predictive models (from destructive methods) and TLS (a non-destructive method) did not show significant differences. The results show that this increasingly accessible technology can be used to adequately estimate forest biomass and volume in a non-destructive manner, which is particularly important in places such as the MMBR.

This study aims to evaluate the effectiveness of machine learning algorithms in predicting key forest metrics—stem volume, root system volume, and organ biomass (including leaves, branches, stem, and root)—for Pinus pseudostrobus var. Lindley, based on morphological measurements from the same trees. The novelty of this study lies in applying five machine learning algorithms—Random Forest, Neural Networks, Gradient Boosting Machines, Support Vector Machines (SVM), and k-Nearest Neighbors (k-NN)—to predict these metrics, using data from the destructive analysis of 98 individual trees aged from eight months to five years. For comparison, we also applied univariate allometric models, adjusted with nonlinear least squares and quantile regression. The results indicate that Random Forest, k-NN, and SVM outperformed the other algorithms, demonstrating superior predictive accuracy for both biomass and volume. A key innovation of this study is its demonstration of how machine learning, with its ability to model complex, nonlinear relationships, can serve as a powerful tool for forest management. Quantile regression, combined with nonlinear least squares, proves most effective when the relationships are well-defined, allowing for tailored parameter adjustments that enhance predictions, particularly in the presence of heteroscedasticity.

In silvicultural management, it is essential to classify forest plantations (FPs) according to productivity. The objectives were to fit models of dominant height growth (Dh) with mixed effects and to construct curves with different site index (SI) classes for plantations of Pinus pseudostrobus and Pinus montezumae in Nuevo San Juan Parangaricutiro, Michoacán, Mexico. In this context, 34 FPs of Pinus pseudostrobus (7–37 years) and 16 FPs of Pinus montezumae (7–32 years) were evaluated through systematic sampling (206 quadrangular sites of 400 m2) and selection of the six top trees in Dh. The age (A) of each plantation was defined and the altitude (Alt), aspect (Asp), and slope (Slop) were recorded. The modified Hossfeld I model showed polymorphic growth trends in Dh at SI of 9, 14, 18, 23, and 28 m for Pinus pseudostrobus at a base age (A0) of 20 years, and anamorphic for Pinus montezumae at SI of 10, 14, 18, 22, and 26 m with A0 of 25 years. The Alt‐Slop and Alt‐Asp combined, explains better the Dh. On average, a technical shift in height and age of maximum current increment was observed for Pinus pseudostrobus of 13 years and 6 years, respectively, whereas, for Pinus montezumae, it is 6 years and 3 years. The fitting using mixed‐effects modeling (MEM) eliminates the random variability in Dh caused by site conditions and reduces the estimation deviations by improving the statistical fitting. This research is partof the first author′s doctoral thesis (Hernandez‐Ramos, 2023).

Introduction Growth dynamics or tree growth response to management in forest plantations can be projected using a Growth and Yield System (TGYS), a useful quantitative silvicultural tool. Objective To develop a TGYS that includes site orientation as a random effect for Pinus montezumae Lamb. and Pinus pseudostrobus Lindl. in Nuevo San Juan Parangaricutiro, Michoacán, Mexico. Materials and methods Data from 58 re-measured sampling plots (400 m2) of P. montezumae and 96 re-measured sampling plots of Pinus pseudostrobus were used. Using a mixed-effects modeling approach, a base model and an algebraic difference approach were simultaneously fitted for each tree measurement variable of interest. Results The growth pattern of dominant height of P. montezumae (polymorphic) and that of P. pseudostrobus (anamorphic) influenced the forecasted trends of basal area and volume when using the fixed parameters of each compatible expression. The annual mortality rate for P. montezumae and P. pseudostrobus was 3.14 % and 3.35 %, respectively. The maximum current annual increment in volume at the best site index was 13.717 m3∙ha-1 at 12 years for P. montezumae, and 23.072 m3∙ha-1 at 15 years for P. pseudostrobus, while volume rotation age happened at 26 years (162.462 m3) and 22 years (321.66 m3), respectively. Conclusions With the developed system, it will be possible to simulate growth scenarios for each forest plantation and support species-specific management strategies.

ntroduction Growth dynamics or tree growth response to management in forest plantations can be projected using a Growth and Yield System (TGYS), a useful quantitative silvicultural tool. Objective To develop a TGYS that includes site orientation as a random effect for Pinus montezumae Lamb. and Pinus pseudostrobus Lindl. in Nuevo San Juan Parangaricutiro, Michoacán, Mexico. Materials and methods Data from 58 re-measured sampling plots (400 m2) of P. montezumae and 96 re-measured sampling plots of Pinus pseudostrobus were used. Using a mixed-effects modeling approach, a base model and an algebraic difference approach were simultaneously fitted for each tree measurement variable of interest. Results The growth pattern of dominant height of P. montezumae (polymorphic) and that of P. pseudostrobus (anamorphic) influenced the forecasted trends of basal area and volume when using the fixed parameters of each compatible expression. The annual mortality rate for P. montezumae and P. pseudostrobus was 3.14 % and 3.35 %, respectively. The maximum current annual increment in volume at the best site index was 13.717 m3∙ha-1 at 12 years for P. montezumae, and 23.072 m3∙ha-1 at 15 years for P. pseudostrobus, while volume rotation age happened at 26 years (162.462 m3) and 22 years (321.66 m3), respectively. Conclusions With the developed system, it will be possible to simulate growth scenarios for each forest plantation and support species-specific management strategies.

Background: Oaxaca is a Mexican region with a high richness of pine trees. However, the specific location where it occurs and the influence of the environment on it is deficient. Questions: Where the greatest richness, diversity and endemism of Pinus species is located in Oaxaca? How does the environment influence the richness, diversity, and endemism of Pinus species in Oaxaca? Studied species: Pinus ayacahuite, Pinus chiapensis, Pinus devoniana, Pinus douglasiana, Pinus hartwegii, Pinus herrerae, Pinus lawsonii, Pinus leiophylla, Pinus maximinoi, Pinus montezumae, Pinus oocarpa, Pinus patula, Pinus pringlei, Pinus pseudostrobus, Pinus tecunumanii and Pinus teocote. Study site: Oaxaca Methods: Occurrences of pine species were collected. From these, spatial cells were delimited, and species and environmental matrices were constructed, with which canonical correspondence analysis was carried out. The richness, diversity, and endemism of pines per cell was calculated, correlating them with physical-environmental parameters. Results: 15 cells with high richness and 17 with high endemism were identified, located in the Sierra Sur, Sierra Norte and La Mixteca regions. Richness, diversity, and endemism were negatively influenced by temperature and compaction soil (r = -0.48, P < 0.01) and positively by topographic (r = 0.43, P < 0.01) and soil parameters (r = 0.45, P < 0.01). Conclusions: The Sierra Norte, Sierra Sur and La Mixteca contain the greatest richness and endemism of pine species in Oaxaca. Richness is positively and negatively related to topographic and temperature variables, respectively.

En la cuenca Amanalco-Valle de Bravo, México, la mayoría de las plantaciones se establecen en parcelas con pasado agrícola e historias de manejo del suelo que determinaron diferentes situaciones iniciales de suministro de nutrientes para los árboles. El objetivo del presente estudio fue evaluar la fertilidad y almacenamiento de carbono orgánico en el suelo de cuatro plantaciones forestales comerciales de pino: (1) Rincón de Guadalupe (Pinus ayacahuite), (2) Loma del Rincón de Guadalupe (Pinus pseudostrobus), (3) San Miguel Tenextepec (Pinus patula) y (4) El Potrero (Pinus patula). En septiembre de 2022 se realizó un muestreo de suelo y se analizaron las siguientes variables: pH, MO, COS, N y P. El pH del suelo, en la plantación de Loma del Rincón de Guadalupe fue neutro y en las otras, moderadamente ácido. Las plantaciones mostraron un nivel bajo de MO, excepto en El Potrero donde se observó un nivel medio. La concentración de N fue mayor en las plantaciones de El Potrero y Loma del Rincón de Guadalupe y menor en San Miguel Tenextepec y Rincón de Guadalupe. El contenido de P fue el siguiente: El Potrero (11.9 %), Loma del Rincón de Guadalupe (8.2 %), San Miguel Tenextepec (1.4 %) y Rincón de Guadalupe (0.3 %). El almacenamiento de COS fue mayor en la plantación de El Potrero, seguido de San Miguel Tenextepec, Loma del Rincón de Guadalupe y Rincón de Guadalupe. Se concluye que las plantaciones forestales analizadas presentaron diferencias en la fertilidad y almacenamiento de C del suelo.

Background: Many landscapes, both natural and anthropogenic, are dominated by degraded soils that have low phosphorus availability due to low overall phosphorus concentration or to phosphorus sequestration by iron-rich minerals. Questions and / or Hypotheses: Does the application of low molecular weight organic acids improve phosphorus availability and plant growth in phosphorus-poor soils, and is this effect modulated by ectomycorrhizal fungi? Studied species / data description /Mathematical model: Pinus pseudostrobus and its ectomycorrhiza Pisolithus arhizus, in addition to six sodium salts of organic acids. Study site and dates: The experiment was carried out in a shade house (35 % shade) in Morelia, Michoacán in 2015. Methods: We conducted experiments with Pinus pseudostrobus and its ectomycorrhiza Pisolithus arhizus in addition to six sodium salts of organic acids. Sodium salts of citrate, oxalate, acetate, tartrate, succinate and malate were added to the soil at 0, 4, 8, 16, 32 and 64 micromolar concentrations. Results: The salts of the organic acids—particularly tartrate and malate-solubilized phosphorus and improved plant growth after 12 months in the absence of P. arhizus. When plants were inoculated with P. arhizus, the effect of most organic acids was either detrimental or non-significant. However, citrate, tartrate and succinate improved biomass and morphological parameters. Conclusions: These results suggest that adding appropriate organic acids to heavily degraded soils can aid P. pseudostrobus establishment and its benefits are higher than the association with mycorrhiza for young plants during the initial stages of fungal colonization.

Aim of study: We assessed potential carbon (C) sequestration in gullies formed in Acrisols and Andosols, on the basis of long-term field restoration trials and GIS analysis. Area of study: Two field trials in Michocán, Mexico, restored with Pinus pseudostrobus, Pinus greggii and Pinus devoniana in 2005 and 2009. Material and methods: Soil C content was analyzed from field samples, and C content of aerial tree biomass of the three Pinus species was estimated by means of allometric equations. The potential restoration area was calculated with a GIS using available layers from the INEGI (Mexican National Institute for Geography and Statistics). Main results: The spatial analysis showed that 1.83% of the Mexican territory are Acrisols and 1.18% are Andosols. From which, 40.87% of Acrisols and 42% of Andosols are eroded. The area with gullies was 2810 km² for both groups of soils within the elevational range of conifer forests in Mexico. C content at the two restored sites was on average of 1.27 t/ha. Soil C content in a 30-cm depth profile was 4.25 t/ha. The potential C sequestration for an average period of 13 years for an area of 2810 km² was 3.947 megatons of C (MtC). A total of four states ‒ Michoacán, Chiapas, Oaxaca, and Puebla ‒ concentrate 89% of the possible capture. Research highlights: Severely degraded sites where gullying is dominant have a high potential for C sequestration once erosion has been controlled and plant cover has been restored.

The spatial distribution of Dendroctonus frontalis Zimmermann, 1868, and Dendroctonus mexicanus Hopkins, 1905, was determined from 2020 to 2021 in the Tixtlancingo ejido. The information came from two surveys because, despite the abundant forested areas in this geographical area of the state of Guerrero, Mexico, economic resources for pest biomonitoring are limited. However, it was possible to identify the presence of 76 outbreaks affecting 1117.697 hectares and 95,078 trees, totaling 14,223.8 m3 of standing timber volume. In 2020, 28 outbreaks were reported, with the eastern spatial distribution showing the most damage from bark beetles, particularly in outbreaks 7 and 14 of the surveyed area. The most affected conifers were Pinus maximinoi H. E. Moore (44.71%), Pinus oocarpa Schiede ex Schltdl. (39.93%), and Pinus pseudostrobus Lindl. (15.36%). The affected timber volume was observed in diameter categories of 30 cm for the three pine species, with infestation of 90,549 trees (13,497.6 m3 t.t.v. (total tree volume)) across 1057.64 hectares. In 2021, 48 outbreaks were recorded, with the northeastern and southern parts of the surveyed area showing the most damage from the bark beetle. The trees most affected by the bark beetle were P. oocarpa (59.17%), P. maximinoi (33.94%), and P. pseudostrobus (6.89%). It was observed that the affected volume occurred in trees with diameter categories of 50 cm for the three pine species, affecting 4529 trees (726.214 m3 t.t.v.) distributed over 60.06 hectares. The contribution of this work lies in establishing a baseline for monitoring damage caused by this beetle, which affects forest resources and diminishes the possibility of maintaining carbon capture areas in the medium and long term, thus impacting the Sustainable Development Goals (SDGs) of the 2030 agenda, specifically Goals 11, 13, and 15.

Genetic variation and phenotypic plasticity in the seasonal shoot growth pattern of Pinus pseudostrobus

A dendrochronological study was carried out with information obtained from the forest plantation of the TecnológicoNacional de México Campus Zitácuaro, where a sample of five trees of the species Pinus pseudostrubus was taken on June 3,2021 and the samples were transferred to the Laboratory of the Faculty of Forest and Environmental Sciences (FCFyA)from the Universidad Juárez del Estado de Durango (UJED) in October 2023. The tree samples were sanded to facilitateobservation of the growth rings, and a stereoscope was used to examine them in detail and precision, in addition, the Velmex"TA" system was used to take measurements of the growth rings, calculating the Annual Current Increase (ICA) and theAverage Annual Increase (IMA). This process included identifying false rings or fluctuations through cuts in the woodslices. The data collected allowed us to understand the growth history of the trees and their response to environmentalconditions.

Mexico is a center of diversity for the genus Pinus, with 44% of pine species being endemic to the country. Mexican pine forests are recognized as hotspots for ectomycorrhizal fungi and bacteria due to the extensive interactions that take place between microorganisms and plants in their roots. These microorganisms play a vital role in the survival of pine species. This study aims to identify fungal and bacterial communities in a relict Mexican pine forest and evaluate the influence of soil physicochemical parameters on microbial composition. Sampling was conducted along a 145 m transect in an isolated natural relict of P. pseudostrobus var. coatepecensis, which is located within a commercial plantation of Pinus patula. A total of 18 soil samples were collected at predetermined distances along the transect, with replicated sampling points as follows: six samples at 20 cm intervals, four samples at 1 m intervals, four samples at 10 m intervals, and four samples at 25 m intervals. The results indicate that fungal composition varies even at short distances and is influenced by the C:N ratio, total carbon (C), total phosphorus (P), and total hydrogen ion concentration (H + ). Ectomycorrhizal fungi (EcM) exhibited a higher relative abundance compared to saprotrophic and pathogenic fungi. A total of 69 EcM ASVs (Amplicon Sequence Variants) were identified, being the dominant genera Tomentella, Clavulina, Suillus, Russula, and Elaphomyces. Bacterial communities did not show significant variation in relation to the distance from the sampling points, but soil pH was identified as the main factor of bacterial composition. Dominant bacterial genera included Burkholderia, Bryobacter, Acidobacterium, and Acidothermus. Additionally, it was observed that current soil conditions influenced β diversity. Overall, the results demonstrate that soil fungal and bacterial communities associated with P. pseudostrobus exhibit a unique composition compared to other natural forest systems in the Neotropics.

Synergistic effects of Amanita stranella and Suillus decipiens inoculation on morphological features and phenolic compounds of Pinus pseudostrobus var. coatepecensis, a narrow endemic Mexican variety

Wood is a biological material with applications in engineering and architecture. Its modulus of rigidity is useful for the calculation of beams that work in bending and torsion. The objective of the research was to determine the rigidity moduli and material indices of Pinus pseudostrobus, Tabebuia rosea and Quercus scytophylla. Dynamic torsion tests were performed on 35 small specimens of each species. Linear correlations and their coefficients for determining the modulus of rigidityas a function of density and frequency were calculated. The main results are: The magnitudes of the wood densities of P. pseudostrobus, T. roseaand Q. scytophyllaare located within the interval:587 kg m-3, 735 kg m-3. The coefficient of variation of the frequencies for Q. scytophyllais 50% lower compared to the coefficients of P. pseudostrobusand T. rosea. The coefficient of variation for P. pseudostrobusis 23% greater than that of T. roseaand 146% greater than that of Q. scytophylla. It is concluded that the values reported in this research may be useful if these wood species are used for structural purposes.

This study aimed to evaluate the tannin content in the bark of five pine species from a forest harvesting area of the Ixtlán de Juárez community, Oaxaca, México. The species studied were Pinus patula, Pinus ayacahuite, Pinus rudis, Pinus douglasiana, Pinus pseudostrobus. The bark samples were subjected to a drying, grinding, and sieving process. These compounds were extracted using two methods: by constant reflux with ethanol for three hours or in a water bath with distilled water for two hours. The percentage of total extract, Stiasny number, and condensed tannins were quantified. The quantitative number of condensed tannins present in the bark for each of the five species studied ranged from 0.65% to 5.14% for the ethanolic extracts and 0.14% to 1.46% for the aqueous extracts. Analysis by Fourier transform infrared spectroscopy (FTIR) identified polyphenolic compounds and functional groups characteristic of tannins. Analysis by scanning electron microscopy (SEM) and X-ray dispersive spectroscopy (EDX) provided the elemental analysis and chemical composition of the tannin extracts, respectively, finding trace elements of silver, cadmium, phosphorus, iodine, and sulfur, which are minerals present in the soil, meaning that through processes of micronutrient absorption, these can interact with the tannins or polyphenols in the barks of the tree species being studied. The results indicate that the bark of P. patula and P. ayacahuite have a higher concentration of condensed tannins, 5.14% and 4.71%, respectively, in the ethanol extraction, and may be susceptible to exploitation due to the amount of bark generated in forestry activities.