Forest Fires, Land Use Changes and Their Impact on Hydrological Balance in Temperate Forests of Central Mexico

Temperate forests play a fundamental role in the provision, regulation, and support of hydrological environmental services, but they are subject to constant changes in land use (clearing, overgrazing, deforestation, and forest fires) that upset the hydrological balance. Through scenarios simulated with the Water Evaluation and Planning (WEAP) hydrological model, the present study analyzes the effects of forest fires and land use changes on the hydrological balance in the microwatersheds of central Mexico. The land use changes that took place between 1995 and 2021 were estimated, and projections based on the current scenario were made. Two trend scenarios were proposed for 2047: one with a positive trend (forest permanence) and the other with a negative trend (loss of cover from forest fires). The results show that with permanence or an increase in forest area, the surface runoff would decrease by 48.2%, increasing the base flow by 37% and the soil moisture by 2.3%. If forest is lost, surface runoff would increase up to 454%, and soil moisture would decrease by 27%. If the current forest decline trends continue, then there will be negative alterations in hydrological processes: a reduction in the interception of precipitation by the canopy and an increase in the velocity and flow of surface runoff, among others. The final result will be a lower amount of water being infiltrated into the soil and stored in the subsoil. The provision of hydrological environmental services depends on the maintenance of forest cover

Record of Morchella tridentina in an Abies religiosa forest in Mexico and in vitro culture of its mycelium with obtaining sclerotia

Antecedentes y Objetivos: El género Morchella agrupa hongos ascomicetos, con varias especies comestibles de gran importancia alimenticia y biotecnológica. En China y Estados Unidos de América se han logrado cultivar exitosamente especies de Morchella de forma artificial hasta producir cuerpos fructíferos. Los objetivos del presente trabajo fueron identificar las especies de Morchella recolectadas en bosque de Abies religiosa, cultivar su micelio in vitro y propagarlo en granos de trigo. El presente estudio contribuye al conocimiento de la fase inicial necesaria para el posible cultivo artificial de este grupo de hongos. Métodos: Se recolectaron hongos en un bosque de Abies religiosa ubicado en Santo Tomás Apipilhuasco, Tepetlaoxtoc, Estado de México, México. Los hongos se identificaron (taxonómica- y molecularmente) y se realizaron aislamientos a partir de trozos de tejido del ascocarpo en medio papa dextrosa agar (PDA) y posteriormente se realizó su propagación en granos de trigo. Resultados clave: Las especies recolectadas fueron identificadas como Morchella tridentina y se logró el cultivo de micelio in vitro en medio PDA, así como su propagación en granos de trigo, en donde se observó la formación de esclerocios después de 21 días de inoculación. Las características del micelio que se cultivó in vitro variaron entre las cepas, no obstante que se aislaron de especímenes pertenecientes a una misma especie. Los especímenes deshidratados fueron depositados en el Herbario CHAP que pertenece a la Universidad Autónoma de Chapingo. Conclusiones: Debido a que las presentes cepas fueron capaces de formar esclerocios, podrían ser utilizadas para la producción de ascocarpos. Sin embargo, es conveniente continuar con la investigación, con el objetivo de determinar las condiciones óptimas (ambientales, sustratos y de inducción de la fructificación) para ese fin y lograr su cultivo artificial.Background and Aims: The genus Morchella groups ascomycete fungi, with several edible species of great nutritional and biotechnological importance. In China and the United States of America, species of Morchella have been artificially cultivated succesfully until producing fruiting bodies. The objectives of this work were: identify species of Morchella collected in an Abies religiosa forest, cultivate their mycelium in vitro and propagate them in wheat grains. The present study contributes to the knowledge of the initial phase necessary for the possible artificial cultivation of this group of fungi. Methods: Mushrooms were collected in an Abies religiosa forest located in Santo Tomas Apipilhuasco, Tepetlaoxtoc, Mexico State, Mexico. Fungi were identified (taxonomically and molecularly) and isolation was realized from pieces from sporome tissue in potato dextrose agar (PDA) medium, followed by propagation in wheat grains. Key results: The species collected were identified as Morchella tridentina and cultivation in vitro of mycelium in PDA was achieved as well as its propagation in wheat grains, where the formation of sclerotia was observed after 21 days of inoculation. The characteristics of the in vitro-cultured mycelium varied among strains, although they were isolated from specimens corresponding to the same species. The specimens were deposited in the CHAP Herbarium, Universidad Autónoma de Chapingo. Conclusions: Because of the presence of strains that are capable to form sclerotia, it could be used for ascocarp production. However, it is convenient to continue with this investigation with the objective of determining the optimal conditions (environmental, substrates, fruiting induction) for this aim and to achieve its artificial cultivation

Structure and tree diversity of secondary dry tropical forests in the Sierra de Huautla Biosphere Reserve, Morelos

"Se estudió la recuperación en riqueza, composición, estructura y diversidad arbórea en 3 condiciones de bosque tropical caducifolio secundario con diferente tiempo de abandono (C35, C45 y C65 años) en el sureste del estado de Morelos. En cada condición se establecieron 3 unidades de muestreo de 50 × 50 m (2,500 m2) y se midieron a todos los individuos ≥ 2.5 cm de diámetro normal (DN). En total se registraron 2,791 individuos, pertenecientes a 79 especies, 53 géneros y 30 familias. Fabaceae fue la familia con el mayor número de especies e individuos. C45 presentó la mayor riqueza de especies (57), seguida de C35 (48) y C65 (43). Las condiciones fueron diferentes (p < 0.0001) en área basal, altura total, DN y cobertura de copa. Las especies con mayores índices relativos de valor de importancia (IVIR) y de valor forestal (IVFR) fueron Pachycereus grandis (IVIR = 22.6, IVFR = 28.7), Amphipterygium adstringens (IVIR = 20.9, IVFR = 17.0), Lysiloma divaricatum (IVIR = 11.2, IVFR = 18.9) y Quercus glaucoides (IVIR = 10.5, IVFR = 13.1). Se encontraron diferencias altamente significativas (p < 0.001) entre condiciones de abandono para la heterogeneidad (Shannon-Wiener: H´), y valores significativamente (p < 0.05) mayores en C65 para el recíproco de Simpson (1/D), así como en C35 y C45 para los índices de Margalef (DMG) y α de Fisher (S). La semejanza florística (Sorensen: Is) fue máxima entre condiciones con menor tiempo de abandono (72%) y mínima con la condición de mayor tiempo (54%). El procedimiento de permutación de respuesta múltiple indicó diferencias significativas (p < 0.05) en la composición de especies entre condiciones tempranas (C35 y C45) y tardías (C65). Estos resultados explican el proceso de la sucesión secundaria en los bosques tropicales caducifolios del área de estudio y dan elementos para efectuar una mejor planificación de las actividades conducentes a su conservación.""The recovery in richness, composition, structure and tree diversity was studied in three conditions of secondary tropical deciduous forest with different time of abandonment (C35, C45 and C65 years) in the southeast of the state of Morelos. In each condition, three plots of 50 × 50 m (2,500 m2) were established and all individuals ≥ 2.5 cm of normal diameter (ND) were measured. In total, 2,791 individuals belonging to 79 species, 53 genera and 30 families were registered. Fabaceae was the family with the largest number of species and individuals. C45 had the highest species richness (57), followed by C35 (48) and C65 (43). The conditions were different (p < 0.0001) in basal area, total height, ND and crown coverage. The species with the highest relative value of importance (IVIR) and forest value (IVFR) were Pachycereus grandis (IVIR = 22.6, IVFR = 28.7), Amphipterygium adstringens (IVIR = 20.9, IVFR = 17.0), Lysiloma divaricatum (IVIR =11.2, IVFR = 18.9) and Quercus glaucoides (IVIR = 10.5, IVFR = 13.1). High significant differences (p < 0.001) between abandonment conditions were found for heterogeneity (Shannon-Wiener: H’), and highest significant values (p < 0.05) for Simpson reciprocal index (1/D) in C65, as well as to Margalef (DMG) and Fisher’s α (S) indexes in C35 and C45. The floristic similarity (Sorensen: Is) was highest among conditions with less time of abandonment (72%) and minimum with the condition of greater time (54%). The multiple response permutation procedure indicated significant differences (p < 0.05) in the species composition between early (C35 and C45) and late (C65) conditions. These results explain the process of secondary succession in the tropical deciduous forests of the study area and provide elements for improve planning of the activities leading to its conservation.

Drought and Vulnerability in Mexico’s Forest Ecosystems

In Mexico, some regions have frequent droughts, while others are beginning to experience their presence and impacts. Therefore, this work aimed to characterize drought in the last twenty-one years and evaluate the vulnerability of forests to this phenomenon. The method consisted of applying the standard precipitation index (SPI-12), calculating the drought vulnerability index (DVI), and applying it to the country’s forest areas. The results confirm that forests are vulnerable to drought for five main reasons. First, geographically, the country has large arid and semiarid areas with little natural precipitation. Second, droughts frequently occur and are present in the national territory, covering from 25% to 75% of the surface in recent years. Third, the socioeconomic characteristics of the population living in municipalities and forest territories increase the vulnerability of these areas to drought. Fourth, drought can trigger other catastrophes, such as fires or forest pests. Fifth, the combination of two or more of the above in the same territory magnifies exposure to drought for both forests and people. Temperate forest ecosystems, in particular, have been subject to the prevalence of drought in recent years and, thus, should receive more attention. Finally, technical and cartographic elements, such as those presented herein, are essential for supporting the formulation of proactive forest response plans to address drought events

Wood anatomy of Fagus grandifolia subsp. mexicana (Fagaceae), endemic species from Mexico

Antecedentes y Objetivos: Fagus grandifolia subsp. mexicana habita en México, formando relictos en el bosque mesófilo de montaña en la Sierra Madre Oriental; es un taxón endémico que actualmente se encuentra en peligro de extinción. El objetivo del estudio fue describir las características anatómicas macroscópicas y microscópicas de la madera de Fagus grandifolia subsp. mexicana con el fin de contribuir a su conocimiento anatómico. Métodos: Las muestras de madera se obtuvieron mediante un método no destructivo que consistió en la extracción de núcleos del fuste de árboles vivos y trozos del tronco de un árbol derribado por el viento. La descripción anatómica de la madera se realizó en los planos tangencial, transversal y radial, a nivel macroscópico con tablillas (7×12×1 cm cortadas y pulidas) y microscópico con preparaciones fijas de cortes de los núcleos, de acuerdo con la terminología propuesta por la International Association of Wood Anatomists; también se estimaron los índices de vulnerabilidad (IV), agrupamiento de vasos (IVg) y mesomorfía (IM). Se empleó el programa RStudio para realizar las pruebas estadísticas y Excel para la estimación de los índices. Resultados clave: La madera de Fagus grandifolia subsp. mexicana es de color castaño claro, brillo medio a alto, veteado pronunciado, hilo recto y textura gruesa, posee porosidad difusa, placa de perforación simple y escalariforme (5-20 barras), punteaduras intervasculares opuestas, tílosis, traqueidas vasicéntricas, fibras libriformes, parénquima axial paratraqueal y apotraqueal difuso, radios heterocelulares uniseriados, biseriados, multiseriados y agregados, cristales prismáticos y cuerpos de sílice. Algunos rasgos anatómicos coinciden con los de otras especies del mismo género.Conclusiones: La descripción anatómica de la madera de F. grandifolia subsp. mexicana es la primera que se realiza para este taxón; además, contribuye a interrelacionar la información de sus características con las de otras especies de Fagus de importancia económica.Background and Aims: Fagus grandifolia subsp. mexicana inhabits Mexico, forming relict in the cloud forests of the Sierra Madre Oriental; it is an endemic taxon that is currently in danger of extinction. The aim of this study was to describe the macroscopic and microscopic anatomical features of the wood of F. grandifolia subsp. mexicana to contribute to its anatomical knowledge.Methods: The wood samples were obtained by a non-destructive method consisting of the extraction of cores from the stem of live trees and pieces of the trunk of one tree that recently had been felled by the wind. The anatomical description of the wood was made in the tangential, across, and radial planes, at the macroscopic level with wooden boards (7×12×1 cm section and polished) and microscopically with fixed slides of core sections. The anatomic description was made following the terminology by the International Association of Wood Anatomists. The Vulnerability index (VI), vessel grouping index (VIg), and mesomorphic index (MI) were also estimated. The RStudio program was used to perform the statistical tests and Excel to estimate the index.Key results: The wood of Fagus grandifolia subsp. mexicana is light brown colored, medium to high gloss, veining pronounced, straight grained and coarse texture, with diffuse porosity, simple and scalariform perforation plates (with 5-20 bars), opposite intervascular pits, tylosis, vasicentric tracheids, libiform fibers, apotracheal axial parenchyma diffuse and apotracheal parenchyma, heterogeneous rays, ray width uniseriate, biseriate, multiseriate and aggregate rays, prismatic crystals and silica bodies. Some anatomical features coincide with those of other species of the same genus.Conclusions: The description of the wood anatomy of F. grandifolia subsp. mexicana is the first for this taxon. Furthermore, it contributes to interrelating the information on its characteristics with that of other Fagus species of economic importance

Sustaining Medicinal Barks: Survival and Bark Regeneration of <i>Amphipterygium adstringens</i> (Anacardiaceae), a Tropical Tree under Experimental Debarking

Commercial harvests can threaten tree species harvested for their bark. Amphipterygium adstringens is a dioecious tree, endemic to the tropical dry forests of Mexico, where it is intensively harvested for its medicinal bark. Limited information hinders developing sustainable management strategies for A. adstringens. We assessed bark regeneration for male and female trees, and evaluated the effect of tree sex and diameter, debarking treatments and cutting seasons on bark regeneration and tree survival rates. Bark regeneration was higher for wet season harvested trees (vs. dry), regardless of their sex. Bark regeneration was higher on female than on male trees. There were significant interactions of harvest season, harvest treatment and tree sex diameter on bark regeneration and survival. Overall, the highest bark regeneration rates occurred in female trees with ≥20.1 cm diameter that were wet season harvested with a 50% debarking intensity. Consequently, wet season and intermediate intensity harvests appear to foster sound management, but we recommend against targeting exclusively a single demographic group (i.e., large female trees) due to potential negative impacts on species demography and bark supply. A grounded strategy for sustaining bark harvest would also need to take into account relevant aspects of local socio-ecological context, including harvest interactions with other land uses

Sustaining Medicinal Barks: Survival and Bark Regeneration of Amphipterygium adstringens (Anacardiaceae), a Tropical Tree under Experimental Debarking

Commercial harvests can threaten tree species harvested for their bark. Amphipterygium adstringens is a dioecious tree, endemic to the tropical dry forests of Mexico, where it is intensively harvested for its medicinal bark. Limited information hinders developing sustainable management strategies for A. adstringens. We assessed bark regeneration for male and female trees, and evaluated the effect of tree sex and diameter, debarking treatments and cutting seasons on bark regeneration and tree survival rates. Bark regeneration was higher for wet season harvested trees (vs. dry), regardless of their sex. Bark regeneration was higher on female than on male trees. There were significant interactions of harvest season, harvest treatment and tree sex diameter on bark regeneration and survival. Overall, the highest bark regeneration rates occurred in female trees with ≥20.1 cm diameter that were wet season harvested with a 50% debarking intensity. Consequently, wet season and intermediate intensity harvests appear to foster sound management, but we recommend against targeting exclusively a single demographic group (i.e., large female trees) due to potential negative impacts on species demography and bark supply. A grounded strategy for sustaining bark harvest would also need to take into account relevant aspects of local socio-ecological context, including harvest interactions with other land uses