Introduction:

Compatibility between the parts involved in grafting is one of the factors defining its success, growth, and productivity.

Objective:

The aim of this study is to determine the effect of the level of taxonomic affinity in the scion/rootstock combination on the survival and shoot growth of reciprocal grafts of Pinus pseudostrobus var. pseudostrobus and P. pseudostrobus var. oaxacana.

Materials and methods:

The effect of the following three factors was determined: (a) three affinity levels, (b) two varieties of P. pseudostrobus and (c) four scion/ rootstock genotypes, on survival and shoot growth (Sg). An ANOVA was performed to determine the effect of factors a, b and c and their interactions on survival and Sg, and a Log-Rank test was carried out for survival analysis.

Results and discussion:

Factor a determined that survival was higher in intervarietal grafts (53.3 %); factor b indicated that grafts with scions of var. pseudostrobus had higher survival (47.2 %); finally, factor c showed the existence of genotypes that increase success if used as scion and decrease if used as rootstock. Sg only showed statistical differences associated with the effect of factor c, being higher for genotype 62 of var. pseudostrobus (18.1 ± 0.63 cm), and in its interaction with factor (a).

Conclusions:

There is an adequate level of compatibility between the two varieties of P. pseudostrobus with significant effect of variety and scion genotype especially in intervarietal grafting (survival greater than 70 %).

Introduction:

Biocomposites reinforced with natural fibers are important for the use of biodegradable and renewable waste.

Objective:

The aim of this study was to evaluate the physical-mechanical performance of a laminar biocomposite developed with a low viscosity epoxy polymer matrix, reinforced with Agave angustifolia Haw. bagasse fibers.

Materials and methods:

Twelve panels were prepared combining three fiber contents (18 %, 24 % and 30 %) with four lengths (1 mm, 3 mm, 6 mm and mixed). Mechanical tests were performed, and the results were compared with the control (pure resin). Three chemical treatments (sodium bicarbonate, vinyl triethoxy silane and sodium hydroxide) and their effect on physico-mechanical properties were evaluated at the fiber-matrix interface; in addition, hybridization with glass fiber was evaluated.

Results and discussion:

Adding fiber reduced the ultimate tensile and flexural strength of the biocomposite by 15.27 %; however, the tensile and flexural moduli increased by up to 1/3 compared to the control. The best chemical treatment (sodium bicarbonate) increased the mechanical properties of the fibers (hardness [46 %] and tensile strength [6 %] and flexural strength [24 %]) and impact strength (38 %), while density and moisture resistance decreased 17 % and 11 %, respectively. The agave/glass fiber combination increased flexural strength up to 77.3 %.

Conclusions:

A. angustifolia fibers have potential to be used in industry, because they improve the mechanical properties of the material; in addition, their use would represent an alternative for managing waste residues.

Introduction:

Ecophysiology and plant responses to environmental factors, such as acclimation to heterogeneous light environments, are important in ecosystems facing degradation and fragmentation processes such as the Tamaulipan Thornscrub (TT).

Objective:

The aim of this study is to evaluate the changes of some morphological and physiological attributes in plants of two representative species of the TT (Prosopis laevigata Humb. et Bonpl. ex Willd and Cordia boissieri A. DC.) grown under different light environments under nursery conditions.

Materials and methods:

Growth, biomass production and chlorophyll concentration were evaluated as responses to three environments: 1) outdoors (OD), 2) 40 % shade (N40) and 3) 60 % shade (N60). Plants were grown in a traditional polyethylene bag system for 17 weeks.

Results and discussion:

Based on diameter growth and biomass production, both species grew better in the outdoor light conditions. The effect of limited light availability was also observed in leaf area and chlorophyll a and b concentrations; these variables increased significantly (P < 0.05) for C. boissieri as shading increased, in contrast to P. laevigata.

Conclusion:

Although the growth of both species is higher in high light levels, C. boissieri shows acclimation strategies suggesting an intermediate tolerance to shade, compared to P. laevigata, which confirms to be light demanding. This information is important for the management of the species according to light conditions in reforestation programs.

Introduction:

The silvicultural objective of pruning is the production of knot-free wood; however, pruning can affect the growth of early-aged trees.

Objective:

The aim of this study was to evaluate the effect of four pruning intensities in a seven-year-old plantation of Pinus patula Schiede ex Schltdl. & Cham.

Materials and methods:

A randomized experimental design with 12 plots (four treatments and three replications) was used; a total of 48 trees were sampled. Pruning treatments were: 1) no pruning, 2) pruning of the lower third of the crown, 3) pruning of the lower half of the crown and 4) pruning of the lower two thirds of the crown. Growth and number of epicormic shoots were measured one year after pruning.

Results and discussion:

The ANOVA showed a significant effect (P < 0.05) of pruning intensity on the variables evaluated. Pruning the lower third of the crown was the treatment with the least amount of epicormic shoots and the greatest increment in height, diameter and volume, while the most intense pruning (lower two thirds of the crown) had the opposite effect.

Conclusion:

More intense pruning negatively affects the growth of P. patula trees in early stages of development.

Introduction:

Large cities have air pollution problems due to the emission of polluting gases and particulate matter (PM).

Objectives:

To know the intra- and inter-annual variation of pollutants (NO_X, CO, O₃, PM₁₀ and PM_2.5) in Mexico City Metropolitan Area and to model their spatial distribution.

Materials and methods:

Data from 44 stations of the Automatic Air Monitoring Network (RAMA) were analyzed to extract information for the pollutants NO_X, O₃ and CO in the period 1986-2021, and PM_2.5 and PM₁₀ in the periods 2000-2021 and 2003-2021, respectively. Monthly averages per station were calculated and the temporal trend of each pollutant was evaluated using the \'Theil-Sen\' operator. The spatial distribution of pollutants was also modeled and the statistical performance of four interpolation methods was compared: Neural Networks, Support Vector Machine, Random Forest and Kriging Universal.

Results and discussion:

NO_X and CO concentrations were high from November to January, while O₃ from April to May. The lowest concentrations of PM₁₀ and PM_2.5 took place from July to October and the highest in May. All pollutants decreased in concentration during the period analyzed, with the most noticeable changes in NO_X (-1.28 ppb·yr^-1)^, while CO had the smallest change (-0.12 ppm·yr^-1). The maximum values for NO_X, O₃ and CO occurred in 1993 and for PM in 2003. The best model was Support Vector Machine, regardless of the pollutant analyzed.

Conclusion:

Spatio-temporal dynamics varied among air pollutants. The analysis with spatial interpolation methods is viable and favors solution strategies to pollution problems.

Introduction:

Land use change due to wind infrastructure establishment can cause ecosystem fragmentation. The result is a new configuration and spatial composition that can be studied by means of landscape and vegetation evaluation.

Objective:

We aimed to characterize the landscape elements in a wind farm area and to recognize the structure and diversity of the fragments identified in the Tamaulipan thornscrub (TT).

Materials and methods:

Land uses were identified using the Normalized Distribution Vegetation Index, whose elements were classified and analyzed using landscape metrics. The plant community preserved in fragments of TT was evaluated by analyzing its structure and tree measurement variables. Diversity and richness indices were calculated, and a Bray-Curtis plot was developed to determine the level of similarity between sites based on species abundance.

Results and discussion:

The multipurpose productive system comprising the study area (14 031.98 ha) included five land uses: agriculture (53.53 %), grassland (25.31 %), TT vegetation (20.63 %), roads (0.51 %) and wind turbines (0.01 %). Fabaceae, Poaceae and Cactaceae families had a greater presence in TT fragments. absolute abundance, canopy cover and average height of tree-shrub stratum was 6 824 individuals∙ha^-1, 224.19 m²∙ha^-1 and 1.64 m, respectively.

Conclusions:

The spatial configuration and floristic composition of the fragments would facilitate the creation of biological corridors under ecological restoration measures. Floristic composition parameters were higher compared to those reported in other TT conservation areas.

Introduction:

Forest diversity and structure are important attributes that can be modified by silvicultural treatments.

Objective:

We compared tree diversity and structure of a temperate forest under the silvicultural treatments of selection and thinning in El Salto, Pueblo Nuevo, Durango.

Materials and methods:

The Shannon diversity index of six sites treated with the selection method and six with thinning was determined in three inventories over a period of 10 years. The diversity among treatments was compared for each inventory using Hutcheson\'s t-test for similarity or difference in diversity-abundance. For each treatment and for the 12 sites, the ecological parameters (abundance, dominance and frequency), importance value index (IVI) and forest volume were analyzed with Kruskal-Wallis tests to determine differences between inventories.

Results and discussion:

A total of 18 species were recorded in the three inventories; Pinus cooperi, P. durangensis and Quercus sideroxyla had the highest IVI. In each inventory, Hutcheson\'s t-test indicated that diversity was significantly higher (P < 0.05) in the selection treatments. On the other hand, in each treatment, the Kruskal-Wallis test showed no significant differences (P > 0.05) in the ecological parameters between inventories; furthermore, tree density, basal area and forest volume of each site showed no significant differences between inventories.

Conclusion:

Diversity was higher for the selection treatment. The ecological parameters were not different between inventories, so the forest structure was not affected at the time of intervention.

Introduction:

The genus Agave, a biological group of cultural and economic importance, is most diverse in Mexico. However, the exact number of species in the state of Hidalgo remains uncertain.

Objective:

The aim of this study is to conduct a systematic literature review to examine the diversity of agave species found in the state of Hidalgo.

Materials and methods:

A comprehensive literature review was conducted using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) protocol, herbarium collections and digital databases were reviewed. A total of 65 informati0on sources were identified, from which 22 were selected to create a database. Species names were reviewed and updated to avoid synonyms and repetitions.

Results and discussion:

A total of 55 species were identified, with 26 having a ‘very likely’ presence in the region. Agave mitis Mart. was the most frequently recorded maguey (19), followed by A. lechuguilla Torr. (17). The species are primarily concentrated in the Barranca de Metztitlán Biosphere Reserve, Valle del Mezquital, and the central part of the state. Agave peacockii Croucher is subject to special protection according to NOM-059-SEMARNAT-2010.

Conclusions:

Hidalgo can be considered among the states with a considerable number of Agave species. The generated information is useful; however, it should be used with caution, as it may be subject to spatial, temporal, and taxonomic biases in inventory data, collections, and lists.

Introduction:

Mosses are pioneer organisms known for their high-water storage capacity and biomass. Consequently, they play a significant structural and functional role in terrestrial ecosystems.

Objective:

The aim of the present study was to analyze whether there is variation in moss biomass and water storage capacity among moss species because of site use and management in a fir forest at Parque Nacional El Chico, Hidalgo, México

Materials and methods:

A total of ten sites were selected, distributed across an altitudinal range of 2 781 to 2 981 m: three in the core zone of the park, three in the buffer zone (tourism without moss extraction), and four in the zone with moss extraction. Plots and subplots were established at each site to estimate the biomass and water storage capacity (WSC) of moss species. Furthermore, the coverage of the herbaceous and shrub strata at the sites was determined.

Results and discussion:

Thuidium delicatulum (Hedw.) Schimp. var. delicatulum predominated in biomass across all sites. The highest moss biomass (0.140 g∙cm^-2) was found in an extraction site (Esquillero), while the highest Water Storage Capacity (WSC) (0.254 g∙cm^-2) was estimated in ecotourism-oriented sites (La Orozca). In sites with moss extraction, coverage of the herbaceous and shrub strata was minimal, and moss biomass increased.

Conclusions:

Use (conservation, ecotourism) and management (extraction) of the forest affects the biomass and WSC values of mosses and the percentage of understory cover (herbaceous and shrubs).

Introduction:

In recent years, species distribution modeling, a technique that allows studying the distribution of organisms in each space, has become widespread.

Objectives:

This study aims to analyze global trends of tree species distribution modeling in the period 1990-2022, by reviewing the scientific literature.

Materials and methods:

We analyzed 250 studies published in 233 scientific articles, 10 book chapters and seven theses, which were consulted in specialized databases.

Results and discussion:

The study variables were analyzed by correlational analysis in 78.4 % of the cases. In 48 countries, the number of studies increased during the last decade; China was the country with the most studies (21.7 %). The analysis included a total of 36 families, 69 genera and 163 species; Pinus pinceana (2.8 %) has been the most studied. The most used model/algorithm for the analysis of species distribution modeling was MaxEnt (72.8 %) and, finally, the variables used were 65, where the one with the highest use was precipitation (4.8 %).

Conclusions:

Tree species distribution modeling should be considered a useful tool for forecasting the potential impacts of climate change. The performance of the modeling will depend on the technique used, as well as on its interpretation, which should be made according to the species and its habitat.