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Natural hybridization can manifest different evolutionary results, such as accelerating differentiation and facilitating speciation through the rapid origin of new biochemical compounds, physiological or morphological phenotypes that allow hybrid species to occupy new habitats, which for parental species would be inaccessible. However, these expectations are not always fulfilled, because natural hybridization between divergent populations can lead to inadequate or unviable hybrids and, therefore, lower forest stability and productivity. Using pure species Pinus arizonica, P. cembroides, P. durangensis, P. engelmannii, P. leiophylla, P. lumholtzii and P. teocote trees and their natural hybrids, this study aims to determine for the first time: (i) morphological differences between pure pine trees and their hybrids molecularly detected, (ii) differences in vigor between 1970 seeds from trees of pure pine species and their hybrid trees (hereinafter called pure and hybrid parents), (iii) differences in vigor between 3465 seedlings from 1421 pure and hybrid parents, and (iv) whether growth of seedlings of hybrid parents is differently associated to parent tree’s environmental conditions, than growth of seedlings of pure parents. The seedlings grew under equal nursery conditions. Our results show some significant differences in morphological traits between the seed trees of pure species and their respective putative hybrid seed trees, and in seed and seedling fitness indices. In contrast to the mean growth of seedlings of hybrid parents, the mean growth of seedlings from pure parents was significantly associated with the parent tree’s bioclimatic conditions studied (R2 = 0.70 vs 0.83). There were only some individuals that presented hybrid superiority.
Javier Hernández-Velasco; José Ciro Hernández-Díaz; J. Jesús Vargas-Hernández; Valerie Hipkins; José Ángel Prieto-Ruíz; Alberto Pérez-Luna; Christian Wehenkel. Natural hybridization in seed stands of seven Mexican Pinus species. New Forests 2021, 1 -23.
AMA StyleJavier Hernández-Velasco, José Ciro Hernández-Díaz, J. Jesús Vargas-Hernández, Valerie Hipkins, José Ángel Prieto-Ruíz, Alberto Pérez-Luna, Christian Wehenkel. Natural hybridization in seed stands of seven Mexican Pinus species. New Forests. 2021; ():1-23.
Chicago/Turabian StyleJavier Hernández-Velasco; José Ciro Hernández-Díaz; J. Jesús Vargas-Hernández; Valerie Hipkins; José Ángel Prieto-Ruíz; Alberto Pérez-Luna; Christian Wehenkel. 2021. "Natural hybridization in seed stands of seven Mexican Pinus species." New Forests , no. : 1-23.
Knowing how and to what extent environmental parameters affect threatened species facilitates the understanding of their specific microhabitat requirements. In this study, we examined the response patterns of four threatened tropical plant species to variations in temperature, precipitation, and physiographic variables, and analyzed the relative contributions of environmental variables to the observed distributions of the species. The studied species are Bursera coyucensis, Cryosophila argentea, Guatteria anomala, and Vatairea lundellii and are cataloged into specific risk categories in the Mexican Official Standard NOM-059-SEMARNAT. Our findings suggest differences in ranges of temperature and precipitation (for example, C. argentea exhibited narrower ranges compared to G. anomala and V. lundellii in precipitation) and similarity in ranges of slope across species distributions. We also found that most species distributions respond non-linearly to variations in environmental variables. These results contribute to defining the environmental spaces of these species. The partial and combined effects of climatic variables, and the range of environmental distributions reported here, have intrinsic implications for the adaptation capacity, plasticity, and survival of these species to environmental variation. This information could be useful to promote conservation activities such as the creation of microhabitats with optimal environmental preferences through sustainable silviculture.
Pablo Antúnez; Christian Wehenkel; Collins Byobona Kukunda; José Ciro Hernández-Díaz. Climatic Variables Differentially Influence Neotropical Plant Species of Conservation Concern. Journal of Sustainable Forestry 2021, 1 -16.
AMA StylePablo Antúnez, Christian Wehenkel, Collins Byobona Kukunda, José Ciro Hernández-Díaz. Climatic Variables Differentially Influence Neotropical Plant Species of Conservation Concern. Journal of Sustainable Forestry. 2021; ():1-16.
Chicago/Turabian StylePablo Antúnez; Christian Wehenkel; Collins Byobona Kukunda; José Ciro Hernández-Díaz. 2021. "Climatic Variables Differentially Influence Neotropical Plant Species of Conservation Concern." Journal of Sustainable Forestry , no. : 1-16.
How coniferous forests evolved in the Northern Hemisphere remains largely unknown. Unlike most groups of organisms that generally follow a latitudinal diversity gradient, most conifer species in the Northern Hemisphere are distributed in mountainous areas at middle latitudes. It is of great interest to know whether the midlatitude region has been an evolutionary cradle or museum for conifers and how evolutionary and ecological factors have driven their spatiotemporal evolution. Here, we investigated the macroevolution of Pinus, the largest conifer genus and characteristic of northern temperate coniferous forests, based on nearly complete species sampling. Using 1,662 genes from transcriptome sequences, we reconstructed a robust species phylogeny and reestimated divergence times of global pines. We found that ∼90% of extant pine species originated in the Miocene in sharp contrast to the ancient origin of Pinus, indicating a Neogene rediversification. Surprisingly, species at middle latitudes are much older than those at other latitudes. This finding, coupled with net diversification rate analysis, indicates that the midlatitude region has provided an evolutionary museum for global pines. Analyses of 31 environmental variables, together with a comparison of evolutionary rates of niche and phenotypic traits with a net diversification rate, found that topography played a primary role in pine diversification, and the aridity index was decisive for the niche rate shift. Moreover, fire has forced diversification and adaptive evolution of Pinus. Our study highlights the importance of integrating phylogenomic and ecological approaches to address evolution of biological groups at the global scale.
Wei-Tao Jin; David S. Gernandt; Christian Wehenkel; Xiao-Mei Xia; Xiao-Xin Wei; Xiao-Quan Wang. Phylogenomic and ecological analyses reveal the spatiotemporal evolution of global pines. Proceedings of the National Academy of Sciences 2021, 118, 1 .
AMA StyleWei-Tao Jin, David S. Gernandt, Christian Wehenkel, Xiao-Mei Xia, Xiao-Xin Wei, Xiao-Quan Wang. Phylogenomic and ecological analyses reveal the spatiotemporal evolution of global pines. Proceedings of the National Academy of Sciences. 2021; 118 (20):1.
Chicago/Turabian StyleWei-Tao Jin; David S. Gernandt; Christian Wehenkel; Xiao-Mei Xia; Xiao-Xin Wei; Xiao-Quan Wang. 2021. "Phylogenomic and ecological analyses reveal the spatiotemporal evolution of global pines." Proceedings of the National Academy of Sciences 118, no. 20: 1.
A seed zone or provenance region is an area within which plants can be moved with little risk of maladaptation because of the low environmental variation. Delineation of seed zones is of great importance for commercial plantations and reforestation and restoration programs. In this study, we used AFLP markers associated with environmental variation for locating and delimiting seed zones for two widespread and economically important Mexican pine species (Pinus arizonica Engelm. and P. durangensis Martínez), both based on recent climate conditions and under a predicted climate scenario for 2030 (Representative Concentration Pathway of ~4.5 Wm−2). We expected to observe: (i) associations between seed zones and local climate, soil and geographical factors, and (ii) a meaning latitudinal shift of seed zones, along with a contraction of species distributions for the period 1990–2030 in a northward direction. Some AFLP outliers were significantly associated with spring and winter precipitation, and with phosphorus concentration in the soil. According to the scenario for 2030, the estimated species and seed zone distributions will change both in size and position. Our modeling of seed zones could contribute to reducing the probabilities of maladaptation of future reforestations and plantations with the pine species studied.
Sergio Simental-Rodriguez; Alberto Pérez-Luna; José Hernández-Díaz; Juan Jaramillo-Correa; Carlos López-Sánchez; Lluvia Flores-Rentería; Artemio Carrillo-Parra; Christian Wehenkel. Modelling Shifts and Contraction of Seed Zones in Two Mexican Pine Species by Using Molecular Markers. Forests 2021, 12, 570 .
AMA StyleSergio Simental-Rodriguez, Alberto Pérez-Luna, José Hernández-Díaz, Juan Jaramillo-Correa, Carlos López-Sánchez, Lluvia Flores-Rentería, Artemio Carrillo-Parra, Christian Wehenkel. Modelling Shifts and Contraction of Seed Zones in Two Mexican Pine Species by Using Molecular Markers. Forests. 2021; 12 (5):570.
Chicago/Turabian StyleSergio Simental-Rodriguez; Alberto Pérez-Luna; José Hernández-Díaz; Juan Jaramillo-Correa; Carlos López-Sánchez; Lluvia Flores-Rentería; Artemio Carrillo-Parra; Christian Wehenkel. 2021. "Modelling Shifts and Contraction of Seed Zones in Two Mexican Pine Species by Using Molecular Markers." Forests 12, no. 5: 570.
Insect damage to cones and seeds has a strong impact on the regeneration of conifer forest ecosystems, with broader implications for ecological and economic services. Lack of control of insect populations can lead to important economic and environmental losses. Pinus strobiformis is the most widespread of the white pines in Mexico and is widely distributed throughout the mountains of northern Mexico. Relatively few studies have examined insect damage to the cones and seeds of these pines, especially in Mexico. In this study, we therefore analyzed insect damage to cones and seeds of P. strobiformis in Mexico by using X-ray and stereomicroscopic analysis. The specific objectives of the study were (a) to characterize insect damage by measuring external and internal cone traits, (b) to assess the health of seeds and cones of P. strobiformis in the Sierra Madre Occidental, Mexico, and (c) to estimate the relative importance of the effects of different environmental variables on cone and seed damage caused by insects. We found that 80% of P. strobiformis seeds and 100% of the tree populations studied had damage caused by insects. Most seeds were affected by Leptoglossus occidentalis, Tetyra bipunctata, Megastigmus albifrons, and the Lepidoptera complex (which includes Apolychrosis synchysis, Cydia latisigna, Eucosma bobana, and Dioryctria abietivorella). The cones of all tree populations were affected by some type of insect damage, with Lepidoptera causing most of the damage (72%), followed by Conophthorus ponderosae (15%), the hemipteran L. occidentalis (7%), and the wasp M. albifrons (6%). The proportion of incomplete seeds in P. strobiformis at the tree level, cone damage by M. albifrons and seed damage in L. occidentalis were associated with various climate and soil variables and with crown dieback. Thus, cone and seed insect damage can be severe and potentially impact seed production in P. strobiformis and the reforestation potential of the species. The study findings will enable managers to better identify insects that cause damage to cone and seeds. In addition, identification of factors associated with damage may be useful for predicting the levels of insect predation on seeds and cones.
Alejandro Leal-Sáenz; Kristen M. Waring; Rebeca Álvarez-Zagoya; José Ciro Hernández-Díaz; Carlos A. López-Sánchez; José Hugo Martínez-Guerrero; Christian Wehenkel. Assessment and Models of Insect Damage to Cones and Seeds of Pinus strobiformis in the Sierra Madre Occidental, Mexico. Frontiers in Plant Science 2021, 12, 1 .
AMA StyleAlejandro Leal-Sáenz, Kristen M. Waring, Rebeca Álvarez-Zagoya, José Ciro Hernández-Díaz, Carlos A. López-Sánchez, José Hugo Martínez-Guerrero, Christian Wehenkel. Assessment and Models of Insect Damage to Cones and Seeds of Pinus strobiformis in the Sierra Madre Occidental, Mexico. Frontiers in Plant Science. 2021; 12 ():1.
Chicago/Turabian StyleAlejandro Leal-Sáenz; Kristen M. Waring; Rebeca Álvarez-Zagoya; José Ciro Hernández-Díaz; Carlos A. López-Sánchez; José Hugo Martínez-Guerrero; Christian Wehenkel. 2021. "Assessment and Models of Insect Damage to Cones and Seeds of Pinus strobiformis in the Sierra Madre Occidental, Mexico." Frontiers in Plant Science 12, no. : 1.
Extant conifer species may be susceptible to rapid environmental change owing to their long generation times, but could also be resilient due to high levels of standing genetic diversity. Hybridisation between closely related species can increase genetic diversity and generate novel allelic combinations capable of fuelling adaptive evolution. Our study unravelled the genetic architecture of adaptive evolution in a conifer hybrid zone formed between Pinus strobiformis and P. flexilis. Using a multifaceted approach emphasising the spatial and environmental patterns of linkage disequilibrium and ancestry enrichment, we identified recently introgressed and background genetic variants to be driving adaptive evolution along different environmental gradients. Specifically, recently introgressed variants from P. flexilis were favoured along freeze-related environmental gradients, while background variants were favoured along water availability-related gradients. We posit that such mosaics of allelic variants within conifer hybrid zones will confer upon them greater resilience to ongoing and future environmental change and can be a key resource for conservation efforts.
Mitra Menon; Justin C. Bagley; Gerald F. M. Page; Amy V. Whipple; Anna W. Schoettle; Christopher J. Still; Christian Wehenkel; Kristen M. Waring; Lluvia Flores-Renteria; Samuel A. Cushman; Andrew J. Eckert. Adaptive evolution in a conifer hybrid zone is driven by a mosaic of recently introgressed and background genetic variants. Communications Biology 2021, 4, 1 -14.
AMA StyleMitra Menon, Justin C. Bagley, Gerald F. M. Page, Amy V. Whipple, Anna W. Schoettle, Christopher J. Still, Christian Wehenkel, Kristen M. Waring, Lluvia Flores-Renteria, Samuel A. Cushman, Andrew J. Eckert. Adaptive evolution in a conifer hybrid zone is driven by a mosaic of recently introgressed and background genetic variants. Communications Biology. 2021; 4 (1):1-14.
Chicago/Turabian StyleMitra Menon; Justin C. Bagley; Gerald F. M. Page; Amy V. Whipple; Anna W. Schoettle; Christopher J. Still; Christian Wehenkel; Kristen M. Waring; Lluvia Flores-Renteria; Samuel A. Cushman; Andrew J. Eckert. 2021. "Adaptive evolution in a conifer hybrid zone is driven by a mosaic of recently introgressed and background genetic variants." Communications Biology 4, no. 1: 1-14.
The particleboard industry faces problems of wood shortage, which has led to the use of non-wood lignocellulosic materials. Furthermore, there is also interest in looking for materials that improve their physical and mechanical properties. The species Luffa aegyptiaca Mill. (fruit), Agave durangensis Gentry (bagasse) and Pennisetum sp. (plant, leaves and stem) could be used in the elaboration of wood-based particleboards. The aim of this study is to determine the feasibility of using these materials to produce particleboards in accordance with their chemical composition. Five materials were studied, A. durangensis (bagasse), L. aegyptiaca (fruit) and Pennisetum sp. (whole plant, leaves and stem). Extractives, holocellulose, Runkel lignin and ash content was determined. The pH of the fibers was also measured and a microanalysis of the ash was performed. ANOVA and Kruskal-Wallis tests were carried out, in addition Tukey and Dunn tests for group comparison were performed. Pennisetum sp. leaves presented the highest total extractives and ash content, while L. aegyptiaca fruit and A. durangensis bagasse had the highest both content of holocellulose and Runkel lignin respectively. The lowest pH was presented by the L. aegyptiaca fruit, while the highest was from the Pennisetum sp. stem. The element with the greatest presence in the five materials was potassium, except in A. durangensis bagasse showing calcium. L. aegyptiaca fruit has better characteristics to be used in particleboards with greater mechanical resistance because of its higher holocellulose content. However, Pennisetum sp. (plant, leaves and stem) could be used to make particleboards with high resistance to water absorption.
Oswaldo Moreno-Anguiano; Artemio Carrillo-Parra; José G. Rutiaga-Quiñones; Christian Wehenkel; Marín Pompa-García; Francisco Márquez-Montesino; Luis F. Pintor-Ibarra. Chemical composition of Luffa aegyptiaca Mill., Agave durangensis Gentry and Pennisetum sp. PeerJ 2021, 9, e10626 .
AMA StyleOswaldo Moreno-Anguiano, Artemio Carrillo-Parra, José G. Rutiaga-Quiñones, Christian Wehenkel, Marín Pompa-García, Francisco Márquez-Montesino, Luis F. Pintor-Ibarra. Chemical composition of Luffa aegyptiaca Mill., Agave durangensis Gentry and Pennisetum sp. PeerJ. 2021; 9 ():e10626.
Chicago/Turabian StyleOswaldo Moreno-Anguiano; Artemio Carrillo-Parra; José G. Rutiaga-Quiñones; Christian Wehenkel; Marín Pompa-García; Francisco Márquez-Montesino; Luis F. Pintor-Ibarra. 2021. "Chemical composition of Luffa aegyptiaca Mill., Agave durangensis Gentry and Pennisetum sp." PeerJ 9, no. : e10626.
The three Mexican spruces’ distributions are fragmented, which could lead to phenological, morphological and genetic differentiation, partially caused by local adaptation. In this study, we examined the effect that climatic variables had on the survival and growth of 5641 Picea seedlings, coming from eight seed provenances of three species and produced in identical nursery conditions. The respective responses of each species and provenance can be considered as a proxy of the genetic differentiation and adaptation of each population. A cluster analysis revealed: (i) significant differences in genetic quantitative traits among the three Picea species and (ii) significant correlations between genetic quantitative traits and climatic factors.
José Marcos Torres-Valverde; José Ciro Hernández-Díaz; Artemio Carrillo-Parra; Eduardo Mendoza-Maya; Christian Wehenkel. Provenance Trials of the Mexican Spruces in Nursery Conditions: Three Species Endangered by Climatic Variation. Environmental Sciences Proceedings 2020, 3, 12 .
AMA StyleJosé Marcos Torres-Valverde, José Ciro Hernández-Díaz, Artemio Carrillo-Parra, Eduardo Mendoza-Maya, Christian Wehenkel. Provenance Trials of the Mexican Spruces in Nursery Conditions: Three Species Endangered by Climatic Variation. Environmental Sciences Proceedings. 2020; 3 (1):12.
Chicago/Turabian StyleJosé Marcos Torres-Valverde; José Ciro Hernández-Díaz; Artemio Carrillo-Parra; Eduardo Mendoza-Maya; Christian Wehenkel. 2020. "Provenance Trials of the Mexican Spruces in Nursery Conditions: Three Species Endangered by Climatic Variation." Environmental Sciences Proceedings 3, no. 1: 12.
The phenotype of trees is determined by the relationships and interactions among genetic and environmental influences. Understanding the patterns and processes that are responsible for phenotypic variation is facilitated by studying the relationships between phenotype and the environment among many individuals across broad ecological and climatic gradients. We used Pinus strobiformis, which has a wide latitudinal distribution, as a model species to: (a) estimate the relative importance of different environmental factors in predicting these morphological traits and (b) characterize the spatial patterns of standing phenotypic variation of cone and seed traits across the species’ range. A large portion of the total variation in morphological characteristics was explained by ecological, climatic and geographical variables (54.7% collectively). The three climate, vegetation and geographical variable groups, each had similar total ability to explain morphological variation (43.4%, 43.8%, 51.5%, respectively), while the topographical variable group had somewhat lower total explanatory power (36.9%). The largest component of explained variance (33.6%) was the four-way interaction of all variable sets, suggesting that there is strong covariation in environmental, climate and geographical variables in their relationship to morphological traits of southwest white pine across its range. The regression results showed that populations in more humid and warmer climates expressed greater cone length and seed size. This may in part facilitate populations of P. strobiformis in warmer and wetter portions of its range growing in dense, shady forest stands, because larger seeds provide greater resources to germinants at the time of germination. Our models provide accurate predictions of morphological traits and important insights regarding the factors that contribute to their expression. Our results indicate that managers should be conservative during reforestation efforts to ensure match between ecotypic variation in seed source populations. However, we also note that given projected large range shift due to climate change, managers will have to balance the match between current ecotypic variation and expected range shift and changes in local adaptive optima under future climate conditions.
Alejandro Leal-Sáenz; Kristen M. Waring; Mitra Menon; Samuel A. Cushman; Andrew Eckert; Lluvia Flores-Rentería; José Ciro Hernández-Díaz; Carlos Antonio López-Sánchez; José Hugo Martínez-Guerrero; Christian Wehenkel. Morphological Differences in Pinus strobiformis Across Latitudinal and Elevational Gradients. Frontiers in Plant Science 2020, 11, 559697 .
AMA StyleAlejandro Leal-Sáenz, Kristen M. Waring, Mitra Menon, Samuel A. Cushman, Andrew Eckert, Lluvia Flores-Rentería, José Ciro Hernández-Díaz, Carlos Antonio López-Sánchez, José Hugo Martínez-Guerrero, Christian Wehenkel. Morphological Differences in Pinus strobiformis Across Latitudinal and Elevational Gradients. Frontiers in Plant Science. 2020; 11 ():559697.
Chicago/Turabian StyleAlejandro Leal-Sáenz; Kristen M. Waring; Mitra Menon; Samuel A. Cushman; Andrew Eckert; Lluvia Flores-Rentería; José Ciro Hernández-Díaz; Carlos Antonio López-Sánchez; José Hugo Martínez-Guerrero; Christian Wehenkel. 2020. "Morphological Differences in Pinus strobiformis Across Latitudinal and Elevational Gradients." Frontiers in Plant Science 11, no. : 559697.
Background The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an ongoing global health crisis, directly and indirectly impacting all spheres of human life. Some pharmacological measures have been proposed to prevent COVID-19 or reduce its severity, such as vaccinations. Previous reports indicate that influenza vaccination appears to be negatively correlated with COVID-19-associated mortality, perhaps as a result of heterologous immunity or changes in innate immunity. The understanding of such trends in correlations could prevent deaths from COVID-19 in the future. The aim of this study was therefore to analyze the association between COVID-19 related deaths and influenza vaccination rate (IVR) in elderly people worldwide. Methods To determine the association between COVID-19 deaths and influenza vaccination, available data sets from countries with more than 0.5 million inhabitants were analyzed (in total 39 countries). To accurately estimate the influence of IVR on COVID-19 deaths and mitigate effects of confounding variables, a sophisticated ranking of the importance of different variables was performed, including as predictor variables IVR and some potentially important geographical and socioeconomic variables as well as variables related to non-pharmaceutical intervention. The associations were measured by non-parametric Spearman rank correlation coefficients and random forest functions. Results The results showed a positive association between COVID-19 deaths and IVR of people ≥65 years-old. There is a significant increase in COVID-19 deaths from eastern to western regions in the world. Further exploration is needed to explain these findings, and additional work on this line of research may lead to prevention of deaths associated with COVID-19.
Christian Wehenkel. Positive association between COVID-19 deaths and influenza vaccination rates in elderly people worldwide. PeerJ 2020, 8, e10112 .
AMA StyleChristian Wehenkel. Positive association between COVID-19 deaths and influenza vaccination rates in elderly people worldwide. PeerJ. 2020; 8 ():e10112.
Chicago/Turabian StyleChristian Wehenkel. 2020. "Positive association between COVID-19 deaths and influenza vaccination rates in elderly people worldwide." PeerJ 8, no. : e10112.
Background Biomass usage for energy purposes has emerged in response to global energy demands and environmental problems. The large amounts of by-products generated during logging are rarely utilized. In addition, some species (e.g., Quercus spp.) are considered less valuable and are left in the cutting areas. Production of pellets from this alternative source of biomass may be possible for power generation. Although the pellets may be of lower quality than other types of wood pellets, because of their physical and technological properties, the addition of different raw materials may improve the characteristics of the oak pellets. Methods Sawdust from the oak species Quercus sideroxyla, Q. rugosa, Q. laeta and Q. conzattii was mixed with sawdust from the pine Pinus durangensis in different ratios of oak to pine (100:0, 80:20, 60:40, 40:60 and 20:80). Physical and mechanical properties of the pellets were determined, and calorific value tests were carried out. For each variable, Kolmogorov–Smirnov normality and Kruskal–Wallis tests were performed and Pearson’s correlation coefficients were determined (considering a significance level of p < 0.05). Results The moisture content and fixed carbon content differed significantly (p < 0.05) between the groups of pellets (i.e., pellets made with different sawdust mixtures). The moisture content of all pellets was less than 10%. However, volatile matter and ash content did not differ significantly between groups (p ≥ 0.05). The ash content was less than 0.7% in all mixtures. The addition of P. durangensis sawdust to the mixtures improved the bulk density of the pellets by 18%. Significant differences (p < 0.05) in particle density were observed between species, mixtures and for the species × mixture interaction. The particle density was highest in the 80:20 and 60:40 mixtures, with values ranging from 1,245 to 1,349 kg m−3. Bulk density and particle density of the pellets were positively correlated with the amount of P. durangensis sawdust included. The mechanical hardness and impact resistance index (IRI) differed significantly (p < 0.05) between groups. The addition of pine sawdust decreased the mechanical hardness of the pellets, up to 24%. The IRI was highest (138) in the Q. sideroxyla pellets (100:0). The mechanical hardness and IRI of the pellets were negatively correlated with the amount of P. durangensis sawdust added. The bulk density of the pellets was negatively correlated with mechanical hardness and IRI. The calorific value of mixtures and the species × mixture interaction differed significantly between groups. Finally, the mean calorific value was highest (19.8 MJ kg−1) in the 20:80 mixture. The calorific value was positively related to the addition of P. durangensis sawdust.
Víctor Daniel Núñez-Retana; Rigoberto Rosales-Serna; José Ángel Prieto-Ruíz; Christian Wehenkel; Artemio Carrillo-Parra. Improving the physical, mechanical and energetic properties of Quercus spp. wood pellets by adding pine sawdust. PeerJ 2020, 8, e9766 .
AMA StyleVíctor Daniel Núñez-Retana, Rigoberto Rosales-Serna, José Ángel Prieto-Ruíz, Christian Wehenkel, Artemio Carrillo-Parra. Improving the physical, mechanical and energetic properties of Quercus spp. wood pellets by adding pine sawdust. PeerJ. 2020; 8 ():e9766.
Chicago/Turabian StyleVíctor Daniel Núñez-Retana; Rigoberto Rosales-Serna; José Ángel Prieto-Ruíz; Christian Wehenkel; Artemio Carrillo-Parra. 2020. "Improving the physical, mechanical and energetic properties of Quercus spp. wood pellets by adding pine sawdust." PeerJ 8, no. : e9766.
The flow of water in temperate forests depends on the amount of precipitation, type of soil, topographic features, and forest cover, among other factors. Unlike the first three, forest cover can be modified by silvicultural treatments, the effects of which manifest in the quality and quantity of water, as well as in the transport of sediments and soil nutrients. The objective of this study was to analyze the effect of some stand variables on surface runoff and stemflow in pine-oak forests of northern Mexico. The stand variables included tree diameter at breast height, basal area, canopy cover, and volume. They were collected in eight 0.1-ha circular plots, measured in 2016 and re-measured in 2018. Nonlinear quantile regression was used to determine the best-fit relationships between the variables. Results indicated that surface runoff was most closely and inversely related to basal area. Stemflow was related to diameter at breast height, while showing no statistical significance. A stemflow funneling ratio did show an inverse, statistically-significant relationship with diameter at breast height. These results can help determine best forest management regimes compatible with the quantity and quality of water fluxes in this type of ecosystem.
Francisco Cruz-Garcia; José Carlos Monárrez González; Aregai Tecle; Christian Wehenkel; Gustavo Perez-Verdin. Effects of stand variables on stemflow and surface runoff in pine-oak forests in northern Mexico. PLOS ONE 2020, 15, e0235320 .
AMA StyleFrancisco Cruz-Garcia, José Carlos Monárrez González, Aregai Tecle, Christian Wehenkel, Gustavo Perez-Verdin. Effects of stand variables on stemflow and surface runoff in pine-oak forests in northern Mexico. PLOS ONE. 2020; 15 (6):e0235320.
Chicago/Turabian StyleFrancisco Cruz-Garcia; José Carlos Monárrez González; Aregai Tecle; Christian Wehenkel; Gustavo Perez-Verdin. 2020. "Effects of stand variables on stemflow and surface runoff in pine-oak forests in northern Mexico." PLOS ONE 15, no. 6: e0235320.
Natural forest regeneration, i.e. self-renewal of forest stands, involves the replacement of old trees by the next generation and is influenced by environmental factors. The spatial structure of tree regeneration depends on and also influences the properties of the stands themselves. Few studies have investigated spatial patterns of naturally regenerated areas in Mexican pine–oak forests, which are considered one of the world’s top 34 biodiversity hotspots. In this study, we analyzed the spatial patterns, particularly the spatial structure, in clusters of naturally regenerated trees in seven 100 × 100 m plots in the Sierra Madre Occidental (northern Mexico), in relation to three factors: slope, geographical aspect and distance between each sapling to the edge of the nearest gap in the canopy. Three indices were used to describe spatial structure and the data were analyzed by bivariate Ripley’s K(t)-functions and three-parameter and six-parameter Weibull models. The results indicate that sapling regeneration was marginal in canopy gaps. Sapling density was ten times higher under the canopy cover, close to the edge than in the gaps. On average, the first maximum number of saplings was detected inside the canopy at about 81 cm from the gap edge, forming ring-type spatial patterns around the canopy gaps. These results contrast with the gap dynamics described in many other studies. We attribute these findings to the nurse effect of trees, which ameliorate abiotic effects, such as the extreme drought that occurred in 2011 and 2012 in the study region. In covered zones close to canopy edges, thece orientation. We recommend adapting or changing the current forest management system to improve continuous forest regeneration (including adaptive silviculture). We also strongly support i) research on the effects of cattle grazing on natural regeneration in the region and ii) reduction of livestock pressure, which is essential to support forest renewal. Complementary reforestation, in addition to maintenance of the few saplings growing within the gaps, may help enhance forest regeneration. Finally, the use of alternative regeneration methods, such as an irregular group shelterwood method (Expanding Gap Silviculture “Femelschlag”), should also be considered, in order to promote natural regeneration more purposefully.
Juan F. Maciel-Nájera; Javier Hernández-Velasco; M. Socorro González-Elizondo; José Ciro Hernández-Díaz; Carlos A. López-Sánchez; Pablo Antúnez; Claudia Edith Bailón-Soto; Christian Wehenkel. Unexpected spatial patterns of natural regeneration in typical uneven-aged mixed pine-oak forests in the Sierra Madre Occidental, Mexico. Global Ecology and Conservation 2020, 23, e01074 .
AMA StyleJuan F. Maciel-Nájera, Javier Hernández-Velasco, M. Socorro González-Elizondo, José Ciro Hernández-Díaz, Carlos A. López-Sánchez, Pablo Antúnez, Claudia Edith Bailón-Soto, Christian Wehenkel. Unexpected spatial patterns of natural regeneration in typical uneven-aged mixed pine-oak forests in the Sierra Madre Occidental, Mexico. Global Ecology and Conservation. 2020; 23 ():e01074.
Chicago/Turabian StyleJuan F. Maciel-Nájera; Javier Hernández-Velasco; M. Socorro González-Elizondo; José Ciro Hernández-Díaz; Carlos A. López-Sánchez; Pablo Antúnez; Claudia Edith Bailón-Soto; Christian Wehenkel. 2020. "Unexpected spatial patterns of natural regeneration in typical uneven-aged mixed pine-oak forests in the Sierra Madre Occidental, Mexico." Global Ecology and Conservation 23, no. : e01074.
For decades there has been confusion and uncertainty on how to clearly identify the two distinct species, Pinus strobiformis Engelm. and Pinus ayacahuite Ehrenberg. Pinus ayacahuite is further defined as two varieties, var. ayacahuite and var. veitchii. These species are of ecological importance throughout much of Mexico because they offer valuable ecosystem services. The objective in this work was to examine the morphological characteristics of cones and seeds from parent trees from six sites in northern Mexico and three sites in southern Mexico. The results show that the mean seed width and length per tree, mean cone weight per tree, and the 100-seed weight per tree were the best variables to accurately separate P. strobiformis from P. ayacahuite. Using these criteria, we found that P. ayacahuite var. veitchii is more similar to P. strobiformis than to P. ayacahuite var. ayacahuite.
Alejandro Leal-Sáenz; Kristen M. Waring; Richard A. Sniezko; Mitra Menon; José Ciro Hernández-Díaz; Carlos Antonio López-Sánchez; José Hugo Martínez-Guerrero; Samantha Del Rocío Mariscal-Lucero; Adrián Silva-Cardoza; Christian Wehenkel. DIFFERENCES IN CONE AND SEED MORPHOLOGY OF PINUS STROBIFORMIS AND PINUS AYACAHUITE. The Southwestern Naturalist 2020, 65, 9 -18.
AMA StyleAlejandro Leal-Sáenz, Kristen M. Waring, Richard A. Sniezko, Mitra Menon, José Ciro Hernández-Díaz, Carlos Antonio López-Sánchez, José Hugo Martínez-Guerrero, Samantha Del Rocío Mariscal-Lucero, Adrián Silva-Cardoza, Christian Wehenkel. DIFFERENCES IN CONE AND SEED MORPHOLOGY OF PINUS STROBIFORMIS AND PINUS AYACAHUITE. The Southwestern Naturalist. 2020; 65 (1):9-18.
Chicago/Turabian StyleAlejandro Leal-Sáenz; Kristen M. Waring; Richard A. Sniezko; Mitra Menon; José Ciro Hernández-Díaz; Carlos Antonio López-Sánchez; José Hugo Martínez-Guerrero; Samantha Del Rocío Mariscal-Lucero; Adrián Silva-Cardoza; Christian Wehenkel. 2020. "DIFFERENCES IN CONE AND SEED MORPHOLOGY OF PINUS STROBIFORMIS AND PINUS AYACAHUITE." The Southwestern Naturalist 65, no. 1: 9-18.
Pinus herrerae and P. luzmariae are endemic to western Mexico, where they cover an area of more than 1 million hectares. Pinus herrerae is also cultivated in field trials in South Africa and South America, because of its considerable economic importance as a source of timber and resin. Seed quality, afforestation success and desirable traits may all be influenced by the presence of hybrid trees in seed stands. We aimed to determine the degree of hybridization between P. herrerae and P. luzmariae in seed stands of each species located in the Sierra Madre Occidental, Durango, Mexico. AFLP molecular markers from samples of 171 trees across five populations were analyzed with STRUCTURE and NewHybrids software to determine the degree of introgressive hybridization. The accuracy of STRUCTURE and NewHybrids in detecting hybrids was quantified using the software Hybridlab 1.0. Morphological analysis of 131 samples from two populations of P. herrerae and two populations of P. luzmariae was also conducted by Random Forest classification. The data were compared by Principal Coordinate Analysis (PCoA) in GenAlex 6.501. Hybridization between Pinus herrerae and P. luzmariae was observed in all seed stands under study and resulted in enhancement of desirable silvicultural traits in the latter species. In P. luzmariae, only about 16% molecularly detected hybrids correspond to those identified on a morphological basis. However, the morphology of P. herrerae is not consistent with the molecularly identified hybrids from one population and is only consistent with 3.3 of those from the other population. This is the first report of hybrid vigour (heterosis) in Mexican pines. Information about hybridization and introgression is essential for developing effective future breeding programs, successful establishment of plantations and management of natural forest stands. Understanding how natural hybridization may influence the evolution and adaptation of pines to climate change is a cornerstone to sustainable forest management including adaptive silviculture.
Christian Wehenkel; Samantha Del Rocío Mariscal-Lucero; M. Socorro González-Elizondo; Víctor A. Aguirre-Galindo; Matthias Fladung; Carlos A. López-Sánchez. Tall Pinus luzmariae trees with genes from P. herrerae. PeerJ 2020, 8, e8648 .
AMA StyleChristian Wehenkel, Samantha Del Rocío Mariscal-Lucero, M. Socorro González-Elizondo, Víctor A. Aguirre-Galindo, Matthias Fladung, Carlos A. López-Sánchez. Tall Pinus luzmariae trees with genes from P. herrerae. PeerJ. 2020; 8 ():e8648.
Chicago/Turabian StyleChristian Wehenkel; Samantha Del Rocío Mariscal-Lucero; M. Socorro González-Elizondo; Víctor A. Aguirre-Galindo; Matthias Fladung; Carlos A. López-Sánchez. 2020. "Tall Pinus luzmariae trees with genes from P. herrerae." PeerJ 8, no. : e8648.
Grafting is one of the most widely used methods for vegetative propagation, particularly for multiplying trees considered important, but there has been little research done on the effect of hybridization on grafts from the genus Pinus. Sometimes hybrids show the ability to reproduce and adapt efficiently to the environment. However, they reduce the genetic gain of seed orchards. The objective in this research was to evaluate the effect of scion grafts from pure species donor Pinus engelmannii Carr. and from putative hybrid trees P. engelmannii × P. arizonica Engelm., grafted on rootstocks of pure species P. engelmannii, along with the effect of the position of the scion in the donor tree crown (upper third and middle third). The scions were collected from three trees of the pure species and three hybrids. In each tree, 20 scions were collected from each third of the crown evaluated. 120 side-veneer grafts were made at the beginning of spring (March) 2018. Variance analyses were performed to evaluate the treatments and adjustments of the Logit and Weibull models to obtain the probability of graft survival. Significant differences were found between the origins of scions (p < 0.0083, after Bonferroni correction), showing grafts with hybrid tree scions taking hold better. In addition, the probability of survival at 5 months after grafting with hybrid tree scions was greater (p < 0.0001) than in grafts with scions from trees of the pure species (Logit model), which coincides with the results of the Weibull model, which indicated that the probability of graft death with pure species donor tree scions is greater than for grafts with hybrid scions. There were no significant differences regarding the position of the scion in the donor tree crown.
Alberto Pérez-Luna; Christian Wehenkel; José Ángel Prieto-Ruíz; Javier López-Upton; José Ciro Hernández-Díaz. Survival of side grafts with scions from pure species Pinus engelmannii Carr. and the P. engelmannii × P. arizonica Engelm. var. arizonica hybrid. PeerJ 2020, 8, e8468 .
AMA StyleAlberto Pérez-Luna, Christian Wehenkel, José Ángel Prieto-Ruíz, Javier López-Upton, José Ciro Hernández-Díaz. Survival of side grafts with scions from pure species Pinus engelmannii Carr. and the P. engelmannii × P. arizonica Engelm. var. arizonica hybrid. PeerJ. 2020; 8 ():e8468.
Chicago/Turabian StyleAlberto Pérez-Luna; Christian Wehenkel; José Ángel Prieto-Ruíz; Javier López-Upton; José Ciro Hernández-Díaz. 2020. "Survival of side grafts with scions from pure species Pinus engelmannii Carr. and the P. engelmannii × P. arizonica Engelm. var. arizonica hybrid." PeerJ 8, no. : e8468.
Rooting substrate and fertilization are key components in the production of containerized seedlings, as they can influence the morphological and physiological characteristics of the plants, which in turn can impact outplanting performance. The objective of the study was to evaluate the effect of four substrates based on mixtures of peat moss (PM), composted bark (CB) and raw pine sawdust (PS), combined with two doses of controlled release fertilizer (CRF) and one non-fertilized control, on the growth of Pinus cembroides Zucc. in the nursery. The treatments were: M1: 50+25+25, M2: 25+25+50, M3: 25+50+25 and M4: 50+50+0 of PM+ CB+ PS (% by volume), respectively. Fertilizer treatments used a controlled release fertilizer (Multicote®): F1: 3 kg m−3 and F2: 6 kg m−3 and a control (WF: with no added fertilizer). The treatments were distributed in a randomized complete block design, with a factorial arrangement of 4 × 3 and six replications. The variables evaluated were: height, seedling diameter, dry biomass, Dickson Quality Index, N, P and K content. Regardless of the substrate, the high fertilizer dose (6 kg m−3) improved most morphological variables. In addition, the high fertilizer dose resulted in foliar N, P and K concentrations within recommended ranges for all substrates. The substrate containing only peat moss and composted bark (M4 + F1 and M4 + F2) had the best growth response. However, the substrate composed of 25% peat moss, 50% composted bark and 25% raw pine sawdust with the high fertilizer dose (M3 + F2) resulted in acceptable seedling growth, and may be preferred if the cost of the substrate is a concern to nursery manager.
Rosa Elvira Madrid-Aispuro; José Ángel Prieto-Ruíz; Arnulfo Aldrete; José Ciro Hernández-Díaz; Christian Wehenkel; Jorge Armando Chávez-Simental; John G. Mexal. Alternative Substrates and Fertilization Doses in the Production of Pinus cembroides Zucc. in Nursery. Forests 2020, 11, 71 .
AMA StyleRosa Elvira Madrid-Aispuro, José Ángel Prieto-Ruíz, Arnulfo Aldrete, José Ciro Hernández-Díaz, Christian Wehenkel, Jorge Armando Chávez-Simental, John G. Mexal. Alternative Substrates and Fertilization Doses in the Production of Pinus cembroides Zucc. in Nursery. Forests. 2020; 11 (1):71.
Chicago/Turabian StyleRosa Elvira Madrid-Aispuro; José Ángel Prieto-Ruíz; Arnulfo Aldrete; José Ciro Hernández-Díaz; Christian Wehenkel; Jorge Armando Chávez-Simental; John G. Mexal. 2020. "Alternative Substrates and Fertilization Doses in the Production of Pinus cembroides Zucc. in Nursery." Forests 11, no. 1: 71.
Jatropha seed is a biomass suitable for bioenergy production that can be produced by smallholders, even on marginal lands. However, the current oilseed production is too low to meet the needs of the planned renewable electricity system in the Galapagos Islands. Pruning and fertilization are management options that can be used to increase the dry seed yields. The effects of both treatments were tested in a split-plot design with jatropha trees, which were monitored during a three-year production period. The average seed production was 643±58 kg ha-1 year-1 in the unpruned trees and 696±50 kg ha-1 year-1 in the pruned trees. Although this difference is small, it is expected to increase over time. The pruned trees developed more slowly than the unpruned trees but showed higher (and still increasing) yields at the end of the three-year test period, while the unpruned trees appeared to have reached their maximum production by the second year of the trial. The low fertilizer doses approved by the smallholders did not have a significant impact on the dry seed yield, and the management options that show benefits in the long term are generally not accepted or adopted by them. Cost-effective nutrient enhancement should be investigated, such as inoculation with arbuscular mycorrhizal fungi.
Álvaro Cañadas-López; Diana Rade-Loor; Marianna Siegmund-Schultze; Jesús Vargas-Hernández; Christian Wehenkel. Pruning and fertilization effects on Jatropha yields under smallholder’s conditions in a Tropical Dry Forest from Ecuador. Revista Facultad Nacional de Agronomía Medellín 2020, 73, 9089 -9097.
AMA StyleÁlvaro Cañadas-López, Diana Rade-Loor, Marianna Siegmund-Schultze, Jesús Vargas-Hernández, Christian Wehenkel. Pruning and fertilization effects on Jatropha yields under smallholder’s conditions in a Tropical Dry Forest from Ecuador. Revista Facultad Nacional de Agronomía Medellín. 2020; 73 (1):9089-9097.
Chicago/Turabian StyleÁlvaro Cañadas-López; Diana Rade-Loor; Marianna Siegmund-Schultze; Jesús Vargas-Hernández; Christian Wehenkel. 2020. "Pruning and fertilization effects on Jatropha yields under smallholder’s conditions in a Tropical Dry Forest from Ecuador." Revista Facultad Nacional de Agronomía Medellín 73, no. 1: 9089-9097.
Background Spatial genetic structure (SGS) analysis is a powerful approach to quantifying gene flow between trees, thus clarifying the functional connectivity of trees at population and landscape scales. The findings of SGS analysis may be useful for conservation and management of natural populations and plantations.Pinus cembroidesis a widely distributed tree species, covering an area of about 2.5 million hectares in Mexico. The aim of this study was to examine five natural seed stands ofP. cembroidesin the Sierra Madre Occidental to determine the SGS at population (within the seed stand) and landscape (among seed stands) levels in order to establish guidelines for the conservation and management of the species. We hypothesized thatP. cembroides, in which the seeds are dispersed by birds and mammals, creates weaker SGS than species with wind-dispersed seeds. Methods DNA fingerprinting was performed using the amplified fragment length polymorphism (AFLP) technique. In order to estimate the SGS at population and landscape levels, we measured the geographical (spatial) distance as the Euclidean distance. We also estimated the genetic distances between individuals using the pairwise kinship coefficient. Results The results showed non-significant autocorrelation in four out of five seed stands studied (i.e., a mainly random distribution in the space of the genetic variants ofP. cembroidesat population level). Discussion SGS was detected at the landscape scale, supporting the theory of isolation by distance as a consequence of restricted pollen and seed dispersal. However, the SGS may also have been generated by our sampling strategy. We recommended establishing a close network of seed stands ofP. cembroidesto prevent greater loss of local genetic variants and alteration of SGS. We recommend seed stands ofP. cembroidesof a minimum width of 225 m.
Luis C. García-Zubia; Javier Hernández-Velasco; José C. Hernández-Díaz; Sergio L. Simental-Rodríguez; Carlos A. López-Sánchez; Carmen Z. Quiñones-Pérez; Artemio Carrillo-Parra; Christian Wehenkel. Spatial genetic structure inPinus cembroidesZucc. at population and landscape levels in central and northern Mexico. PeerJ 2019, 7, e8002 .
AMA StyleLuis C. García-Zubia, Javier Hernández-Velasco, José C. Hernández-Díaz, Sergio L. Simental-Rodríguez, Carlos A. López-Sánchez, Carmen Z. Quiñones-Pérez, Artemio Carrillo-Parra, Christian Wehenkel. Spatial genetic structure inPinus cembroidesZucc. at population and landscape levels in central and northern Mexico. PeerJ. 2019; 7 ():e8002.
Chicago/Turabian StyleLuis C. García-Zubia; Javier Hernández-Velasco; José C. Hernández-Díaz; Sergio L. Simental-Rodríguez; Carlos A. López-Sánchez; Carmen Z. Quiñones-Pérez; Artemio Carrillo-Parra; Christian Wehenkel. 2019. "Spatial genetic structure inPinus cembroidesZucc. at population and landscape levels in central and northern Mexico." PeerJ 7, no. : e8002.
Lack of knowledge regarding the fuel quality of diverse tree species prevents their use. Furthermore, the potential use of wood with the bark of different tree species for pellet production is still relatively unexplored in the scientific literature. In Mexico, the sawdust of Quercus genus (oak) is underutilized, despite it being an important forest resource, due to some anatomical and technological characteristics. The sawdust of Quercus with bark is also considered to have a low economic value. The objective of this study was to analyze the energy characteristics of barked and debarked Quercus sideroxyla, Q. rugosa, Q. laeta, and Q. conzattii in order to evaluate their potential for pellet production. Granulometric distribution, bulk density, proximal analysis, and calorific value tests were carried out. The sawdust of the four tree species studied was in accordance with the limits established by the standard EN 14961-2. Sawdust with a particle size of 0.425 mm had the highest percentage of retained mass (30.33%) (p < 0.05) in the granulometry test. There were no statistical differences in granulometry (p > 0.05) between barked and debarked sawdust for all Quercus species. Barked sawdust presented higher bulk density (p < 0.05) than debarked sawdust (246 and 224 kg/m3, respectively). The moisture content did not show statistical differences (p > 0.05) between barked and debarked sawdust. The volatile material was higher (p < 0.05) in debarked sawdust (88.7%) than in barked sawdust (85.0%). The ash content was below 0.5%. The fixed carbon was higher (p < 0.05) in barked sawdust (14.6%). The calorific value was higher (p < 0.05) in barked sawdust and for the Q. rugosa species (19.5 MJ/kg). The results suggest that the oak species analyzed, both barked and debarked, showed good potential for pellet production. Future studies should quantify fuel quality for a variety of diameter distributions, and analyze pellet mechanical properties and ash slagging risk.
Víctor Daniel Núñez-Retana; Christian Wehenkel; Daniel José Vega-Nieva; Juan García-Quezada; Artemio Carrillo-Parra; Núñez- Retana; Vega- Nieva; García- Quezada; Carrillo- Parra. The Bioenergetic Potential of Four Oak Species from Northeastern Mexico. Forests 2019, 10, 869 .
AMA StyleVíctor Daniel Núñez-Retana, Christian Wehenkel, Daniel José Vega-Nieva, Juan García-Quezada, Artemio Carrillo-Parra, Núñez- Retana, Vega- Nieva, García- Quezada, Carrillo- Parra. The Bioenergetic Potential of Four Oak Species from Northeastern Mexico. Forests. 2019; 10 (10):869.
Chicago/Turabian StyleVíctor Daniel Núñez-Retana; Christian Wehenkel; Daniel José Vega-Nieva; Juan García-Quezada; Artemio Carrillo-Parra; Núñez- Retana; Vega- Nieva; García- Quezada; Carrillo- Parra. 2019. "The Bioenergetic Potential of Four Oak Species from Northeastern Mexico." Forests 10, no. 10: 869.