Revista Mexicana de Ciencias Forestales

Physica and chemical evaluation of a Vertisol in two land uses in Northeastern Mexico

2025-05-03T06:27:33+00:00

The conversion of forest areas into agricultural and livestock lands, as well as intensive practices can cause soil degradation. The objective of this study was to analyze the effects of land use change on the physical (Bulk Density [BD], Porosity [P], Texture, Mechanical Resistance to Penetration [MRP]) and chemical properties (Organic Matter [SOM], Organic Carbon [%C], pH and Electrical Conductivity [EC]) of a Vertisol at different depths (0-5, 5-15, 15-30, 30-60 and 60-100 cm); considering that most research focuses only on the evaluation of the first centimeters of soil, so there is lack of knowledge and uncertainty about the behavior of edaphic variables in greater depth ranges. In each land use, four soil samples composed of depth (n=40) were collected. The chemical variables did not present significant differences between land uses, but between depths. The SOM and %C decreased significantly as depth increased, where the highest values were recorded at 0-5 cm in both land uses. The pH was moderately alkaline, while the EC was below salinity levels. In regard to physical properties, only BD and porosity showed significant differences between land uses (p<0.05); between depths, only the contents of sand and silt varied. MRP only presented differences between land uses (p<0.01). Vertisol presented greater sensitivity in the physical properties of the soil after the conversion of the Tamaulipan Thorny Scrubto Grassland.

Diameter at breast height and basal area growth for Pinus durangensis Martínez in Madera, Chihuahua State

2025-01-07T19:53:59+00:00

Growth models are an efficient tool that helps to plan the application of silvicultural treatments in forest management. This study focused on fitting equations with fixed and random effects to predict the growth in diameter at breast height and basal area of Pinus durangensis in a forest community called Cebadilla de Dolores ejido, Madera municipality, state of Chihuahua, Mexico. Data from stem analysis of 27 trees were used (measured in 2021), obtaining slices at 1.30 m height and commercial measurements. Seven growth models were fitted, selecting the best one using 10 fitting statistics (e. g., R², RMSE, AIC); in addition, the mixed-effects model procedure with fixed and random parameters at the individual tree level was used. The use of mixed-effects models provided estimates that allowed modeling the variability of diameters and basal area in terms of age. The results showed that age explained more than 98 % of the variability in diameter and basal area, with RMSE of 0.91 cm and 0.002 m², respectively. The Chapman-Richards model was the most effective for modeling the growth of the variables studied, with very efficient fitting statistics. In addition, mixed effects improved predictions at the individual tree level, incorporating fixed and random parameters.

Tapering and implied volume equations for Pinus leiophylla Schiede ex Schltdl. & Cham. in state of Michoacán

2025-05-03T06:27:45+00:00

The description of the taper (di) and the precise estimation of the stem volume (sV) are fundamental in the estimation of the timber stock and the distribution of products. The objective of the study was to fit a taper function and define the implicit sV model for Pinus leiophylla trees in the indigenous community of Patambán, Tangancícuaro, state of Michoacán, Mexico. Eight taper functions were fitted using data from 36 dominant trees from forest plantations (245 normal diameter [d], diameters [di] and heights [Ai] at different stem sections). Mixed effects models (MEM) and the maximum likelihood technique were utilized to correct for heteroscedasticity and self-correlation with the expression varExp: and a moving average (ARMA) structure of order (p, q), respectively. Statistically, Clutter’s taper expression: was more accurate as it included the random effect ( ) additively in the total height parameter (Th). The explanation of sampling variability was 97.8 %, with an overall estimation error of 1.406 cm and an individual bias of 0.0138 cm. The implicit sV model was Schumacher-Hall: (d and Th in m). The proposed expressions can be reliably included in the description of inventory data or yield estimates for forest crops.

Carbon composition and storage in palms of the Andean-Amazonian hotspot, Ecuadorian piedmont forest

2025-05-03T06:27:21+00:00

Within the context of climate change, Ecuador's forest palms are crucial both for biodiversity and for the local communities that depend on them for food and building materials. This study analyzes the diversity of palms and their carbon storage capacity in an Ecuadorian Amazon forest, and highlights their socioeconomic importance. An allometric measurement methodology adapted to local conditions was used to determine biomass and carbon stocks. The diameter at breast height and total height revealed that Iriartea deltoidea and Oenocarpus bataua are the species with the highest carbon sequestration rates, especially in low altitude areas. A notable decrease in carbon storage capacity was observed with increasing altitude, with averages of 11.20 Mg ha^-1 in the area at 600 to 701 masl, and 3.11 Mg ha^-1 within an altitude interval of 901 to 1 000 masl. In addition to their relevance for climate change mitigation, these species are essential for local communities, providing them with food, building materials, and materials for handicraft products. There is a considerable need to develop conservation strategies focused on low altitude areas with high palm density and promote the sustainable use of their derived resources for local economic benefits. Also, it is urgent to implement more accurate allometric models to improve biomass and carbon stock estimates in order to reinforce their integration into global conservation policies.

Aboveground forest biomass estimation at the individual tree level using terrestrial LiDAR

2025-05-03T06:27:08+00:00

Forest ecosystems play a key role in carbon storage, highlighting the importance of accurately estimating the tree biomass. The objective was to estimate the forest biomass using a laser scanner (LiDAR, Light Detection and Ranging), specifically a terrestrial device (TLS, Terrestrial Laser Scanner), at the individual tree level. Thirty-one trees were selected from a Pinus cooperi regular stand, whose diameter at breast height (DBH) and height (h) variables were measured in a traditional way. TLS data were collected with a model Focus M70 FARO® laser scanner and processed to three-dimensionally model the logs and calculate their biomass. These data were compared with estimates obtained by allometric equations and traditional measurements. Results indicate that the TLS is accurate in measuring diameters (R2=0.72 and RMSE=1.28 cm), compared to traditional methods. However, it underestimates the tree height (R2=0.79 and RMSE=1.68 m), affecting the accuracy of the biomass calculation. Although the TLS provided acceptable estimates, these were lower than those obtained using allometric equations. In conclusion, TLS is a promising tool for nondestructive biomass studies. Future work should consider in greater detail the influence of the characteristics of the studied area, the scanning methodology, and the algorithms applied in the estimation of biomass.