Introduction

Measuring gains and losses in land use and vegetation allows us to understand the dynamics of changes in natural protected areas.

Objectives

To analyze changes in land use and vegetation in the Forest Protected Area of the southern rivers of Querétaro.

Materials and Methods

The areas of land use and vegetation were quantified for the years 1997, 2009, and 2016. Changes and trends were analyzed using geographic information systems. Possible causes of the dynamics of change were examined based on field visits and a socioeconomic survey in five localities (94 households) within the area of influence.

Results

The net loss over the 20 years was 1 026 ha (16 %) of oak forest and 472 ha (100 %) of pine-oak forest. Secondary shrubby oak forest increased from 21 ha to 1 088 ha (+5 000 %). Vegetation associated with productive activities such as induced pastureland increased 119 ha (98 %), while agriculture expanded 128 ha (6 %). Survey information indicates that 11 % are engaged in agriculture and 30 % use firewood as an energy source; furthermore, 90 % perceive that illegal logging is associated with high charcoal production.

Conclusion

The dynamics of land use and vegetation changes from 1997 to 2016 is moderate with losses of forest importance such as oak forest, caused by human activities according to the perception of the villagers.

Introduction

Secondary vegetation in the state of Campeche forms the basis of agricultural and forestry production, and its biological capital depends on the fallow period elapsed.

Objective

To evaluate the potential of secondary vegetation to provide commercially valuable timber forest products (xiles and polewood) for construction.

Materials and methods

Areas with secondary vegetation (20 to 30-years fallow) and mature vegetation (>60 years fallow) were selected in forest lands of the Nuevo Becal ejido, Calakmul, Campeche. In both conditions, nine sampling units (20 x 25 m) were randomly established, where structural attributes and floristic composition were measured and compared. In the secondary vegetation, the density and volume of forest products were estimated and compared with harvested data.

Results and discussion

In the region, secondary vegetation is 60 % more diverse than mature vegetation. Secondary vegetation has greater richness (P < 0.0001), number of individuals (P < 0.0001), and basimetric area (P < 0.0001) of species useful for xiles and polewood compared to mature vegetation. Of the estimated forest products (xiles, polewood, and poles), 31 % are effectively harvested. The sale of timber products is considered profitable, potentially reaching 251 530 MXN·ha^-1; however, the amount could be higher with targeted forest management practices.

Conclusions

Products such as xiles and polewood, are found in greater quantity and quality in secondary vegetation. Commercial use of secondary vegetation could reduce pressure on mature forests in the region.

Introduction

Mexico is the thirteenth largest cocoa-producing country in the world, yielding 20 000 tons (0.4 % of world production). Cocoa pod husks (CPH) represent an opportunity for the extraction of value-added products due to their chemical properties.

Objective

To determine the antioxidant activity, mineral profile and main chemical constituents of CPH (Theobroma cacao L. var. Carmelo).

Materials and Methods

The study quantified and determined the main organic and inorganic constituents of the CPH sample using analytical techniques (Technical Association for the Pulp and Paper Industries [TAPPI], American Society for Testing and Materials [ASTM] and other methods reported in the literature).

Results and discussion

A 19.4 % extractable content in organic solvents was obtained. The cellulose content was 30.5 %, hemicellulose 19 %, lignin 23.3 %, and ash 7.7 %. The total phenolic content was 24.59 ± 0.93 mg gallic acid equivalents∙g^-1, and the flavonoid content was 2.35 ± 0.24 mg catechin equivalents∙g^-1. The antioxidant activity was determined as 304.84 ± 57.59 mg trolox equivalents for ABTS (2,2′-azino-bis[3ethylbenzothiazoline-6-sulfonic acid]) and 145.80 ± 3.84 mg trolox equivalents for FRAP (ferric reducing antioxidant power).

Conclusions

CPH is a viable source of lignin, and its cellulose and hemicellulose contents have the potential to serve as a carbohydrate source for biofuel production. Additionally, its high polyphenol content and antioxidant capacity position it as a promising source for the food and/or pharmaceutical industry.

Introduction

Fuel studies provide information on fire danger, fire behavior, greenhouse gas emissions, and fuel management.

Objective

To establish relationships between fuel variables, leaf area index, and solar radiation to estimate fuel loads in a Pinus hartwegii Lindl. forest and subalpine grassland at the Iztaccíhuatl-Popocatépetl National Park.

Materials and methods

Fuels (load, cover, height, or depth), forest stand (tree measurement variables), and solar radiation (diffuse, direct, total area and clearing) were sampled. Relationships between variables were determined using linear regression using the coefficient of determination, significance, normality, homoscedasticity, multicollinearity, and autocorrelation.

Results and discussion

In the forest, the average load was 27.9 Mg∙ha^-1, with nearly 60 % of leaflitter and fermentation layer. There are direct relationships between grass cover and clearing; woody material load and leaf area index; and total fuel load with leaflitter depth and fermentation layer. Conditions with higher radiation promote greater grass load, while low radiation facilitates the accumulation of woody materials, leaflitter, and the fermentation layer. In the grassland, the load reached 6.8 Mg∙ha^-1, and there was a direct relationship between total fuel load and cover.

Conclusions

In the P. hartwegii forest and grassland, statistical models were found that relate forest fuel loads with radiation variables or with variables specific to the fuels, which expedites estimates and supports decisions for fuel management.

Introduction

The analysis of land cover and land use change (LCLUC) allows the identification of factors that generate changes in ecosystems.

Objective

To analyze the dynamics of LCLUC in a micro-watershed of the Pantepec river in the Otomí-Tepehua region, Hidalgo, for the period 1993-2018.

Materials and methods

Using vector data from series II (1993), IV (2007), and VII (2018) from the Instituto Nacional de Estadística y Geografía (INEGI) and an unsupervised classification in QGIS 2.18.10, seven categories of land use and land cover were identified. The MOLUSCE (Modules for Land Use Change Evaluation) tool in QGIS 2.18.10 was used to obtain change matrices and maps. Consequently, the rate of change, loss, gain, total and net change, and exchange between categories were calculated for three analysis periods.

Results and discussion

From 1993 to 2018 there was a process of loss and gain for cloud forest with a rate of change of -3.21 %, driven by induced grassland and rainfed agriculture with rates of change of 3.75 and -2.38 % respectively. Over 25 years, rainfed agriculture decreased by 57 % in area, while induced grassland expanded by 251 %.

Conclusions

Land use categories with significant changes are located around San Bartolo Tutotepec, influenced by anthropogenic activities. There are variations in the forest categories, attributed to changes in the INEGI classification methodology between series II, IV and VII.

Introduction

Fuelwood is one of the most important energy sources in rural areas. Studies focus on evaluating firewood usage patterns only in the domestic sector, but there is scarce attention given to firewood as an economic activity.

Objective

To determine the consumption patterns and preferences for firewood use in two rest areas in Lagunas de Montebello National Park, Mexico.

Materials and methods

Firewood consumption was assessed by semi-structured interviews and direct measurement. Indices of cultural use value and relative importance (biomass and frequency) were used to determine the most important species. Differences in consumption patterns throughout the year were analyzed with Student’s t-tests.

Results and discussion

The diners’ kitchens depend on the purchase of firewood as the main energy resource with a monthly investment of 1 408.33 ± 836.7 MXN and an average consumption per diner of 21.1 ± 10.1 kg∙day^-1. Consumption varied between low vs. high season (t = 2.4478, p = 0.018), being higher in high season (25.3 ± 10.0 kg∙day^-1 vs. 19.1 ± 9.6 kg∙day^-1). The most important species, culturally valued for their use in cooking, were Pinus sp., Quercus sapotifolia Liebm., Liquidambar styraciflua L., and Quercus sp.

Conclusion

The diversified use of firewood is changing to a specific and simplified one, which could promote the illegal trade of the product. Reforestation programs and dendroenergy plantations are needed to support the sustainable use of this resource.

Introduction

The dendrochronological potential of a species indicates its ability to form annual tree rings that capture a clear climate signal.

Objective

To evaluate the dendrochronological potential of Pinus pinceana Gordon to record climate variability in its tree rings.

Materials and methods

Cores from P. pinceana were extracted in a submontane scrub vegetation in Tamaulipas, Mexico. Dendrochronology software was used to measure the annual tree-rings width, date the tree rings, and transform them into growth indices. These indices were then correlated with precipitation and temperature data.

Results and discussion

The correlation between series was r = 0.54 (p < 0.001) and mean sensitivity was 0.31. These values are lower than documented for the species; however, they indicate that the species is sensitive to climatic factors and can record its variability through their tree-ring width indices. A 153-year chronology (1867-2019) was generated with potential to detect variability in average cumulative September-May precipitation (r = 0.71; p < 0.001) and average maximum temperature September-June (r = -0.64; p < 0.001). Weeping pinyon in Tamaulipas overcomes the sensitivity to precipitation that the species shows in other populations of central and northern Mexico.

Conclusions

P. pinceana in Tamaulipas has good dendrochronological potential due to its ability to record regional climate variability, particularly precipitation, in its tree- rings.

Introduction

Altitude variation can influence the diversity and structure of a forest.

Objective

To assess the diversity, horizontal structure, and tree associations of a conserved temperate forest using an elevation gradient.

Materials and methods

The research was conducted at the Thick-billed Parrot Sanctuary at three altitudinal intervals: 1) 2 307 to 2 466 m, 2) 2 466 to 2 625 m and 3) 2 625 to 2 785 m. Horizontal structure was determined with the importance value index (IVI); analysis of variance and Tukey\'s test (p < 0.05) were performed for the Shannon-Wiener diversity index, Pielou\'s evenness and Margalef\'s richness. Similarity was determined with the Morisita-Horn index.

Results and discussion

Three families, five genera and seven species were recorded; Pinus strobiformis Engelm. had the highest IVI with values above 25 %. The Pinaceae family is the most representative with three species in risk category. Abundance decreased as altitude increased (p < 0.05). Dominance showed an upward trend in relation to altitude, in contrast to true diversity and evenness; however, there were no significant differences between intervals (p > 0.05). Richness was not related to altitude and floristic similarity was high (75 to 93 %) among the three intervals.

Conclusions

Dominance, diversity and evenness indices were similar in the three intervals. Floristic similarity suggests that altitude variation may lead to a gradual change in composition.

Introduction

We found two new records of Cantharellus species during surveys in the pine forests of Pico de Orizaba National Park. These wild fungi have consumption, economic and sociocultural value in the Mountain Region, Veracruz, Mexico.

Objective

To identify and morphologically characterize the ectomycorrhizal Cantharellus species collected at Pico de Orizaba National Park.

Materials and methods

Fungi collection took place from June to November using systematic sampling for four years (2019-2022) in Pinus hartwegii, P. montezumae, and P. pseudostrobus forests in the municipality of Calcahualco, Veracruz. Specimens were morphologically characterized and molecularly identified using concatenated sequences of transcription elongation factor 1-alpha (tef1-α) and the internal transcribed spacer region (ITS3C and ITS4).

Results and discussion

Phylogenetic analyses based on molecular data from the main clades of Cantharellus (125 sequences) confirmed the new records of Cantharellus roseocanus (GenBank access: OQ875962 [ITS2] and OQ876856 [tef1]) and Cantharellus flavus (GenBank access: OQ875963 [ITS2] and OQ876857 [tef1]). The morphological differences between C. roseocanus and C. flavus are notable: C. roseocanus is characterized by its convex cap and thin gills, while C. flavus has a flatter, more robust cap; additionally, differences in aroma and flavor are relevant to their culinary use.

Conclusions

The new records of C. flavus and C. roseocanus in the temperate forests of Pico de Orizaba National Park contribute to the taxonomic understanding of the genus Cantharellus, which still lacks complete elucidation.

Introduction

Grevillea robusta is an ornamental forest species with a distinctive tree architecture, featuring branches that form an open and spacious canopy, making it an attractive option for urban and peri-urban reforestation.

Objective

To describe the architectural model of G. robusta and analyze its morphometry in five diameter categories.

Materials and methods

The study was carried out in peri-urban areas of Texcoco, Estado de México. Fourteen tree-measurement characteristics were evaluated for 31 individuals classified into five diameter categories to identify the architectural model. An ANOVA was used to detect significant differences among diameter categories, and a Student\'s t-test was applied to compare the defined architectural models. The relationship between diameter at breast height, total height, and canopy coverage was assessed using linear and non-linear regression.

Results and discussion

G. robusta conformed to the Stone model for smaller diameter categories (7.5 cm-12.49 cm, 12.5 cm-17.49 cm, 17.5 cm-22.49 cm) and to the Attims model for larger categories (22.5 cm-27.49 cm and 27.5 cm-32.49 cm). Total height, crown height, third-order branch length, and leaf blade length and leaf base varied significantly (p = 0.05) among diameter categories. The Hossfeld IV model adequately described the relationship between diameter at breast height and total height, while linear regression proved suitable for diameter at breast height and crown coverage.

Conclusion

Diameter category influences the morphometric attributes and architecture of G. robusta. These results are relevant for the planning and use of this species in urban and peri-urban areas.