Revista Mexicana de Ciencias Forestales

Growth and stem quality of Southern black pine provenances in Metepec, State of Mexico

2025-11-25T06:46:40+00:00

In Mexico, the Southern black pine (Pinus greggii var. australis) is widely used for timber plantations and reforestation, but it is necessary to assess its performance at specific sites in order to select superior genotypes. The objective of this research study was to determine differences among provenances in terms of growth and stem quality, as well as to evaluate their relationship with environmental variables. The assessment was conducted in a provenance trial of eight sources of Southern black pine, established in Metepec, State of Mexico. All variables showed significant differences among provenances (p≤0.0002), except for branch angle and diameter (p≥0.3558). The provenances El Madroño, El Cobre and El Pinalito exhibited the highest survival rates (69.57 to 79.54 %). La Parada, El Madroño, El Pinalito, El Cobre and La Cebada showed higher stem volume (115.1 to 134.6 dm³), periodic annual increment in diameter at breast height (1.83 to 2.14 cm), and in height (0.80 to 0.84 m). La Parada, Molango, El Madroño and La Cebada produced the straightest stems, whereas El Cobre, El Piñón and Ponthadó showed fewer growth units and branches. Growth variables were positively correlated with latitude (r≥0.711, p≤0.048), while the number of growth units and stem straightness were correlated with precipitation (r≥0.761, p≤0.028) and branch diameter was correlated with latitude and altitude (r≥0.714, p≤0.047). El Madroño is recommended for both reforestation and timber plantations due to its high survival, growth performance, and stem quality.

Loss of forest ecosystems in the Monarch Butterfly Biosphere Reserve (1994-2023)

2025-11-25T06:47:22+00:00

The Monarch Butterfly Biosphere Reserve (known as RBMM by its Spanish acronym) is a key area for the hibernation of the monarch butterfly (Danaus plexippus), as it plays a significant role in its migratory and reproductive cycle. However, this ecosystem faces substantial threats due to increased anthropogenic activities and the effects of climate change ―situations that jeopardize both the species' continued existence in Mexico and the reserve's biodiversity. The objective of this study was to evaluate the loss of forest ecosystems in the RBMM during the 1994-2023 period, using a multitemporal analysis of high-resolution satellite images. The results revealed that 6 389 ha of forest cover had been lost in the RBMM by 2023; reductions by vegetation type were 87 % for oak forest, 69 % for pine forest, and 42 % for mesophilic mountain forest, compared to their extent in 1994. These findings show a worrying decline in forest cover, which compromises the integrity of the monarch butterfly's habitat and highlights the need to implement effective conservation strategies.

Comparison of models to estimate DBH of Pinus hartwegii Lindl. with LiDAR data

2025-11-25T06:46:50+00:00

DBH is a fundamental variable in forest management. Airborne LiDAR sensors have demonstrated their usefulness in supporting forest inventories; however, it is not possible to directly measure DBH with them. Pinus hartwegii is the main tree species in the highlands of Mexico, providing important ecosystem services such as carbon sequestration and rainwater infiltration. The objective of this study was to design an equation to estimate the DBH of individual P. hartwegii trees, based on tree measurements obtained from airborne LiDAR data. 85 identifiable P. hartwegii trees were selected on a digital orthomosaic and their UTM coordinates were recorded. With these coordinates they were located in the field and their DBH, total height, height to crown base and crown diameter were measured. They were located in a LiDAR point cloud and the same variables were measured as in the field, except for the DBH. 29 models reported in the literature were evaluated to estimate normal diameter, using 7 independent variables obtained from the LiDAR data. The best model (M27) is an adaptation of the one known in the literature as Gompertz. It obtained an R²adj=0.884, RMSE=6.5 cm. The validation results indicate that its estimates are adequate for calculating the DBH from the total height and crown diameter obtained from LiDAR data.

Spatial modeling of the conservation state and future scenarios in Eastern Tabasco, Mexico

2025-11-25T06:47:12+00:00

Land use change in Eastern Tabasco (ET) was modeled using the Land Change Modeler (LCM) for the ecological sustainability module of the TerrSet liberaGIS^® software, covering the period 2000-2019. In addition, a probabilistic and spatial scenario (2030) was created using Markov chains and Cellular automata. The results indicated that during 2000 and 2019, agricultural and forest uses dominated, together accounting for 60 %. The rest of the land cover types covered a small area: water bodies and wetlands (7.9 %), evergreen rain forest (5 %), medium evergreen and semi-evergreen forest (2.4 %), lowland floodplain forest (2.6 %), and fallow lands (14.8 %). The spatial projection to the year 2030 pointed to a slight increase in agricultural use (60.3 %), human settlements (1.5 %), and oil palm plantations (2.1 %). Although productive activities will continue to dominate, high, medium, and low forests will remain stable at 5.2, 2.8, and 2.6 %, respectively, contrary to the situation of water bodies and wetlands, which will continue to lose significant areas, as indicated by the spatial projection. In order to preserve the remaining forests and those wetlands that still exist, it is important that ecological zoning plans have clear criteria for ecological regulation and a vision of sustainable development. Likewise, conservation, restoration and sustainable use of the Usumacinta Canyon Flora and Fauna Protection Area and the Wanhá Biosphere Reserve must be strengthened.

Changes of the vegetation structure and composition along an altitudinal and antropogenic gradient

2025-08-04T18:25:30+00:00

Few studies have examined how human activities influence the structure and composition of vegetation ecological patterns along altitudinal gradients, to identify areas with different resilience or susceptibility. This study evaluated the impact of anthropogenic effects on the composition and structure of an Abies religiosa forest in the Magdalena River basin, near Mexico City. We established 15 plots, each measuring 30×30 m², at three different altitudes: high (3 449 masl), intermediate (3 202 masl), and low (3 092 masl). Some environmental variables and calculated indexes of anthropogenic disturbances, including human activities, livestock presence and deforestation were assumed. Changes in composition and structure were analyzed using a dissimilarity model and multivariate analysis. Our findings recorded a total of 42 species, consisting of eight tree species and 34 herb species. Notably, mid-altitude plots, despite experiencing a high level of livestock activities, displayed greater species richness in both the understory and canopy. The trees in these plots, ranging from 20 to 40 m high, contributed to a larger basal area and showed a direct response to light and temperature. In contrast, the lower-altitude plots had the greatest basal area attributed to trees around 10 m tall. The results showed that altitude and anthropogenic disturbance are determining factors in the patterns of plant diversity and composition, in the canopy structure and in the understory.

Changes in soil carbon quantity and quality due to forest harvesting

2025-11-25T06:46:29+00:00

Soil is the main carbon reservoir in forest ecosystems. Forest harvesting may alter both the quantity and quality of soil organic carbon (SOC) and its respiration potential; however, few studies have addressed these effects. This study aimed to quantify organic carbon mass to 80 cm depth, the C/N ratio, and estimate the potential CO₂ respiration of surface soil (0-15 cm) in Abies religiosa stands with (CA) and without (SA) timber harvesting. The study was conducted in Atlautla, State of Mexico, where three harvested stands (three years after logging) and three unharvested stands were selected. Comparisons between sites were made using the Mann-Whitney test (p>0.05). No significant differences were found in bulk density, SOC content, or potential respiration between CA and SA stands. The C/N ratio was significantly lower at 45 cm depth in SA stands, indicating more labile carbon. Respired carbon represented 4.6 and 6.3 % of total SOC for CA and SA stands, respectively. Although this result was contrary to expectations, since soil disturbance from logging could enhance carbon oxidation, it was consistent with the trend of lower C/N ratio, suggesting higher labile soil carbon in SA sites. Due to the short post-harvest period (three years), low harvesting intensity, and high natural soil variability, detecting changes in soil carbon mass and quality caused by forest harvesting is difficult.

Biomass and dry leaf yield of Lippia graveolens Kunth

2025-11-25T06:47:01+00:00

With n = 88 Lippia graveolens plants, green weight (gwe) and leaf dry weight (ldw) biomass tables were estimated in northern Zacatecas, Mexico. The morphometric variables were measured in the field: plant height (h, cm), minor diameter (mid, cm), major diameter (mad, cm) of the shrub cover, average diameter (cav, cm), green weight (gwe) and leaf dry weight (ldw). Regression models selected by the following were adjusted to estimate gwe and ldw were fitted: the probability of committing a Type I error (P<0.01) in the regression, the highest adjusted coefficient of determination (R²_aj), minimum values for the root mean square error (RMSE) and coefficient of variation (CV). The average gwe was 149.4 ± 62.9 g plant^-1 and ldw was 31.1 ± 13.8 g plant^-1, respectively. The average density was 8 272 plants ha^-1. To estimate the biomass, the model gwe=(22.063)(1.050)^cav was chosen (P<0.01, R²_aj=0.979, RMSE=0.064, CV=1.29%). For the dry weight, ldw=(10.933)(1.027)^cav (P<0.01, R²_aj=0.909, RMSE=0.075, CV=2.21%). The adjustments in the selected models showed that the morphometric variable cav of L. graveolens predicts the gwe and ldw at a reliability of 95% in the study area of the present investigation.