Revista Bosque

Protection measures for the Araucaria Forest and their efficiencyin the conservation of Araucaria angustifolia in southern Brazil

2023-12-03T03:02:33+00:00

Forests require sustainable management due to the long cycle of the species, for the balance of the ecosystem, on structure or processes on which the species depend and for the socioeconomic development. This study shows the effect of protection measures (no management, conservation) and their results for the structure of the forest available in official publications and scientific articles. These studies have used statistical methods and compile different information techniques from inventories and scientific research (diagnosis and applied analysis) that evaluated, compared results and presented conclusions on the subject. We argue that there are uncertainties about the threat of extinction and that the lack of management can increase disinterest in the forest resource. The overexploitation of edible seeds can destabilize the dynamics and regeneration of the forest ecosystem. The ecosystem, economic, structure, diversity, reproduction and production losses of forest masses due to non-use of resources are greater than the benefits. The results indicated the need for sustainable forest management as a public policy for the conservation of the species and the Mixed Ombrophilous Forest in southern Brazil.

Assessing genetic diversity of Dalbergia stevensonii: an endangered species in Guatemala

2023-10-12T13:54:03+00:00

Owing to extensive overexploitation and continuous habitat loss in recent decades, Dalbergia stevensonii has become endangered in Central America and its place of origin. Genetic diversity is essential for ensuring the long-term survival of the species and is vital in breeding programs. However, knowledge of the genetic diversity of D. stevensonii is limited, as no study has been conducted to estimate the population variability in Guatemala. This study is the first to determine the genetic diversity and structure of wild populations of D. stevensonii in Guatemala using molecular markers. The genetic diversity of 90 wild D. stevensonii trees from six populations located in their natural range is currently being evaluated. Genetic diversity was moderate, with an average of 5.83 alleles per locus, a mean Shannon index value of 1.42, and observed and expected heterozygosity of 0.32 and 0.37, respectively. AMOVA indicated that only 6 % of the genetic variation was between populations, and genetic distance values (pairwise F_ST) suggested moderate differentiation between populations. STRUCTURE and DAPC analyses revealed the existence of three clusters for the 90 samples, while the genetic differentiation among populations is attributed more to genetics than to geographic distance. Conservation of the genetic diversity of D. stevensonii is critical to ensure its long-term survival, and the success of breeding programs focused on improving the traits and characteristics of the species, such as growth rate, wood quality, and resistance to pests and diseases. These findings provide a crucial genetic basis for conservation, management, and restoration of this endemic species.

Internal trunk decay indicators of ash tree (Fraxinus uhdei) in the Molino de Flores Netzahualcoyotl National Park, Mexico

2023-11-20T15:14:32+00:00

The evaluation of the structural trunk condition is fundamental in determining the risk to people and urban infrastructure. The objectives were: 1) to evaluate indicators of the presence and severity of internal decomposition of the trunk of ash (Fraxinus uhdei) in the Molino de Flores Netzahualcóyotl National Park, 2) to determine the association between the basic visual level of risk and the severity of decay, and 3) determine the external visual characteristics of the tree that influence the probability of the presence of internal trunk decay. The risk of 50 trees was evaluated using the Porkorny method and the presence of decay was determined using a resistograph in two areas of the trunk: 30 cm (Base) and 1.3 m (DN) height from the ground. The severity of decay was determined by the sound wood- stem radius ratio. In general, the presence of internal decomposition was 30 %, being more frequent and severe in the base area than in the DAP. There is a moderate negative association between decay severity and risk rating. Finally, the presence of external visual indicators of decay at the base of the trunk and the presence of exposed roots with lesions are the two factors that predict the presence of internal decay of the ash tree trunk. These results contribute to the generation of more accurate ratings in basic level risk assessments.

Germination tests and plant production of provenances-progenies of Pinus patula

2024-03-14T13:50:26+00:00

The low quality of plants produced in nurseries has added to the high mortality rates in plantations established in Mexico. The objective of this study is to evaluate the effect of three sowing dates and the provenance of the germplasm on the plant quality of Pinus patula, in addition to evaluating the effectiveness of four pre-germination treatments: i) control, ii) soaking in water for 12-hour and storage at 3 °C for five weeks, plus 12-hour soaking before sowing, iii) storage at 3 °C for five weeks and 12-hour soaking before sowing, and iv) 12-hour soaking before sowing. The height, diameter at the root neck, robustness index, and germination efficiency of the provenance progenies of P. patula in the nursery were evaluated, in addition to daily and accumulated germination in the laboratory. Data were analyzed using ANOVA, Kruskal-Wallis tests, Tukey means, and Dunn’s medians. In addition, the response variables were correlated with the bioclimatic variables of the provenances. Statistical differences were found in plant quality according to provenance. Families from Pinal de Amoles, Querétaro presented the lowest robustness index (6,61). The seeds had a higher germination (92,3 %) when soaked for 12 h and stored at 3 °C for five weeks, plus soaking in water for 12 h before sowing. The quality and germination of P. patula are influenced by its provenance, sowing date, and pregerminative treatments.

Diversity and ecosystem services in tree cover of the overlap zone of the National Natural Park of Macuira, La Guajira - Colombia

2023-03-23T18:58:03+00:00

The present study evaluated the ecosystem services (ES) associated with the woody vegetation located in the overlap zone characterized as Tropical Dry Forest in the serrania Macuira where communities of the original Wayuu people settle. The open shrubland (OS) and dense shrubland (DS) vegetation covers were evaluated, three sampling points per cover were selected, in which circular plots with an area of 1.000 m² were identified, for a total of 3.000 m² per vegetation cover and in each plot, the inventory of the tree component with DBH > 5 cm was carried out. In the study, 20 woody species were found, belonging to 12 families, Fabaceae/Faboideae, Fabaceae/Mimosoideae, Fabaceae/Caesalpinioideae and Cactaceae were the most represented families. The species with the highest dominance in OS was Prosopis juliflora (IVI 157,3% and concentrated 51,7% of individuals) and in DS Handroanthus billbergii (IVI 116,8% and concentrated 32% of individuals); the biodiversity indices did not show statistical differences between the vegetal covers; however, the accumulation curves suggest that in terms of richness the covers differ. The ES carbon storage showed significant statistical differences, the DS accumulated 25,4 ± 2,2 t C ha^-1 and the OS 9,9 ± 2,2 t C ha-1, which means a monetary value per hectare of $466,5 USD and $182,5 USD. Fifteen species with a use value greater than three were determined, the most important uses being forage and construction (94 % of the species), followed by fuel, sawmilling and fruits for animal feed.

Inoculation of Neltuma alba with arbuscular mycorrhizal fungi: effects on growth and edaphic variables in Entre Ríos, Argentina

2024-01-11T17:59:17+00:00

Neltuma alba (algarrobo blanco) is a commercially valuable native in Argentina that is of interest for the restoration of degraded soils. Incorporation of arbuscular mycorrhizal fungi (AMF) has been suggested to benefit plants during field establishment. The aim of this study was to evaluate the edaphic properties and growth of N. alba plantations inoculated with AMF isolated from the Chaco Region of Argentina six years after field establishment. The treatments consisted of plants inoculated with AMF isolated from two sites: Colonia Benitez (CB, Chaco Province, humid site) and Padre Lozano (PL, Salta Province, semi-arid site). The uninoculated control (TE) group was maintained. Survival, collar diameter, and total plant height were measured. Additionally, composite soil samples were collected per treatment to determine physical, chemical, and biological variables. Regardless of inoculation, the incorporation of trees had positive effects on the evaluated edaphic properties. Soil samples from plants inoculated with CB showed higher values of total biological activity, electrical conductivity, pH, exchangeable calcium, and soil respiration. In contrast, soil samples from plants inoculated with PL showed higher organic matter content. N. alba plants inoculated with AMF from CB exhibited the lowest growth rates under the environmental conditions evaluated.

Biochar and chicken manure improve soil chemical properties and nutritional status of rosewood seedlings grown in clay soil

2024-03-05T15:42:10+00:00

Studies on the effect of biochar and chicken manure on soil chemical properties and initial growth of rosewood under field conditions in the Amazon are rare, therefore a field experiment was carried out to evaluate the effects of biochar, manure of chicken and mineral fertilizer on the chemical properties of the soil, nutrient concentrations in the leaves and on the initial growth of rosewood (Aniba rosaeodora) grown in clayey soil. The study was conducted in causal blocks, with five treatments (control, biochar, biochar and chicken manure, biochar and mineral fertilizer, biochar, chicken manure and mineral fertilizer) and three replications. We observed that, in general, the application of biochar and chicken manure, alone or in combination, increased soil pH, calcium, magnesium, phosphorus, zinc and manganese contents, as well as foliar potassium and calcium concentrations. On the other hand, despite fertilization, we did not observe significant gains in the growth of A. rosaeodora seedlings until ten months after planting. The combination of biochar and chicken manure exhibited the greatest impact and is therefore an important ally for soil sustainability and plant development in tropical soils.

Biomass distribution in components of Pinus patula in reforestations in the Sierra Norte of Oaxaca, Mexico

2023-08-04T15:43:18+00:00

A system of allometric equations was generated and evaluated to estimate the total biomass and its components during the reforestation of Pinus patula in Sierra Norte of Oaxaca State, Mexico. For this purpose, 18 trees were directly sampled, which represented the growth potential of the site. Using this destructive method, the fresh weight in situ, and samples of each component of the tree were obtained to estimate the dry weight. The total tree biomass was related to its normal diameter by adjusting allometric equations using regression techniques. The exponential equation was selected to estimate the total biomass because it presented the best statistical indicators. The exponential model was again fitted to each component by using a system of simultaneous equations. The allometric equations obtained showed good performance in estimating aerial biomass in components and total tree biomass in the reforestation of Pinus patula, with similar diameters and environmental conditions. The distribution of aerial biomass estimated in the field was 69.8 % for stems, 20.5 % for branches, and 9.7 % for foliage.

Anatomical characterization of wood from three tree species from a floodplain forest, Central Amazon, Brazil

2024-01-11T14:13:40+00:00

The anatomical structure of wood from tree species found in floodplain forests can undergo alterations due to seasonal fluctuations in water levels, potentially affecting the volume of wood available for sustainable forest management in inundated areas. Thus, this study aims to characterize the anatomical features of Hura crepitans, Ocotea cymbarum and Eschweilera albiflora, assessing whether these characteristics differ from descriptions reported in previous studies of the same species conducted in other environments. Samples were collected from six adult trees of each species in two sustainable development reserves (SDR), Mamirauá and Amanã, located in the middle Solimões region, state of Amazonas, using a non-destructive method with an increment borer. Two samples were collected from three different heights (0.30, 1.30, and 2.30 m). Microscopic descriptions of the species were determined (porosity, axial parenchyma, rays, fibers, and vessel elements). Two-way factorial ANOVA followed by Tukey’s post hoc test was used to verify the differences in the anatomical elements of the wood samples collected at the three heights. The wood of H. crepitans has diffuse porosity, a predominance of solitary vessels, diffuse-in-aggregates, scarce axial parenchyma, non-storied rays, and libriform fibers. The wood of O. cymbarum has solitary vessels in radial multiples, vasicentric axial parenchyma, non-storied rays, and septate fibers. E. albiflora has a radial grouping of vessels, banded parenchyma, and non-storied rays. This study confirms previous descriptions of this species, revealing that its anatomical characteristics remain constant throughout the trunk.

Biometrics and seed germination of Eremanthus incanus (Asteraceae): strategies for valorization, conservation, and cultivation

2024-04-07T16:52:51+00:00

Eremanthus incanus is a native tree of Brazil with economic, ecological, and social importance, but it faces risks due to predatory exploitation and a lack of research. The objective of this study is to evaluate the biometrics and seed germination of different mother trees in order to contribute to the valorization, conservation, and cultivation of the species. Phenotypically, 10 mother trees were selected from a Candeia population located in the Diamantina region of Minas Gerais, from which seeds resulting from open pollination were collected. For the biometric analysis, 100 seeds from each mother tree were randomly sampled, distributed on millimeter paper in four repetitions of 25 units each, and evaluated for weight, length, and width. The germination study began with disinfestation and selection of seeds using the densimetric method. Subsequently, the material was placed in germination boxes containing germitest paper. The experiment was set up in BOD (Biochemical Oxygen Demand) germination chambers following a randomized block design, with ten mother trees and four repetitions of 25 seeds per plot. Germination was evaluated on alternate days, until a constant point was reached. Significant effects of E. incanus mother trees were observed on biometric variables as well as on the germination rate and germination speed index of the seeds. Understanding these effects advances knowledge about the species and its potentialities, contributing to the development of more efficient propagation and conservation strategies.

Evaluation of the plant growth promoting capacity of rhizobacteria of Algarrobo Neltuma pallida from dry forest of Piura – Perú, Laboratory and effect of seed germination

2023-07-12T19:45:57+00:00

The main goal of this study is to isolate, select and determine the growth plant promoting ability of rhizobacteria in the stump and in the carob tree at the laboratory and seed level in order to have a bank of strains that can be used for the reforestation of the dry forest in Piura. Two composite samples of rhizosphere soil were obtained: one from stumps (felled trees) and the other from algarrobo trees, of which 16 and 18 bacterial strains were isolated, respectively. Measurements at a laboratory level included free nitrogen fixation, indolacetic acid, cellulolytic, and phosphate solubilizing production capacity. For each soil sample, five strains were selected with complementary (not antagonistic) properties to make an inoculating liquid and evaluate its effect on seed growth: 53 % for stumps, 37 % for trees, and 34 % for control (water). Inoculant strains were molecularly identified as Actinomycetes and other strains as Bacillus sp., B. paramycoides, B. wiedmannii, B. thuringiensis, and B. subtilis. Therefore, it was demonstrated that the rhizosphere of a dry forest carob, whether as a tree or stump, is an important source of rhizobacteria with plant-promoting capacity, which can be used to reforest the dry forest.

Identifying illumination configurations that optimize the classification of mountainous forest types in satellite images: An approach based on 3D modelling

2023-10-05T01:32:27+00:00

The conservation of biodiversity in the tropics has prompted the need for extended and accurate forest inventories in mountainous landscapes, where satellite imagery and radiative transfer modeling of forests have acquired much relevance. Last-generation classification algorithms (i.e. machine learning) using terrain information have proven useful for mapping forest types, however, the accuracy of classifications is measured on average over a large extent, and little emphasis has been placed on predicting which illumination configurations could in fact cause high uncertainty in the classification results. This paper presents a 3D modeling approach adapted to the Discrete Anisotropic Radiative Transfer (DART) image simulator, which indicates whether forest types are distinguishable in a set of steep terrain configurations. The approach also describes a comparison of simulated and real forest scenes on slopes at high (4 m) spatial resolution. This method was applied to estimate the spectral separability of three forest types (oak, pine, and high tropical forests) on steep terrain in Mexico. For extreme (low or high) solar incidence angles, the pine and high tropical forests were indistinguishable, and by contrast, they were distinguishable on slopes near to the solar perpendicular plane. As a consequence, to maximize favourable slope configurations, we recommend to incorporate images acquired in the morning and in the afternoon for machine learning classification algorithms.

In this paper, we present a 3D modeling approach, adapted to the Discrete Anisotropic Radiative Transfer (DART) image simulator, that indicates if forest types are distinguishable or not in a set of steep terrain configurations. The approach also describes the comparison of simulated and real forest scenes on slope at high resolution. The method was applied for the estimation of the spectral separability of three forest types (oak, pine and high tropical forests) on steep terrain in Mexico. The spectral separability between pine and tropical forests depended on the slope aspect, presumably because of structural similarities in the canopy. Recommendations are made in terms of classification expectations and simplifying assumptions in the 3D modeling of complex forests.

Remote sensing of forest fine-scale gap dynamics: A case study on lenga beech forests in Argentina

2024-03-22T15:39:10+00:00

Sustainable forest management is of crucial importance due to the manifold ecosystem services forests provide for society. The forests of South America are characterized, on the one hand, by a high degree of naturalness and, on the other hand, by signs of degradation by grazing, unsustainable timber use, the invasion of non-native tree species and anthropogenic fire. Accordingly, modern inventory and management tools are necessary. We analysed Landsat time series from 1998 to 2020, additionally accompanied by images from 1985, 1986, 1987 and 1992 in order to detect the fine-scale gap dynamics of Nothofagus pumilio forests in central Patagonia, Argentina. The dense time series is extracted from annual image composites obtained with an algorithm based on the Best Available Pixel (BAP) approach. A time series is developed for each study plot, building it with the spectral values of the pixel on the centre of the plots. The method proved to be useful in identifying the time and intensity of changes in tree structure at pixel scale. Accordingly, it can be part of a continuous forest monitoring and supports forest management by providing a cheap proxy indicator of important natural phenomena occurring in remote forest sites. We finally point to the importance of combining remote sensing and terrestrial approaches for modernize forest inventories.