Cerne Journal: Top 10 Most Accessed Articles in May 2026

1- INFLUENCE OF CLONE-SITE INTERACTION ON BASIC WOOD DENSITY OF Eucalyptus CLONES IN BRAZILIAN TROPICAL ZONES

Maria Naruna Felix de Almeida, José Luiz Louzada, José Eduardo Macedo Pezzopane, Sofia Maria Rocha, Ana Paula Câmara, Vaniele Bento dos Santos, Thayanne Caroline Castor Neto, Otávio Campoe, Rafaela Carneiro, Clayton Alcarde Alvares, Graziela Baptista Vidaurre

Abstract

Background: Contrasting edaphoclimatic differences will influence the development of Eucalyptus forests, resulting in varying responses according to the clone. This study aimed to evaluate the impact of clone x site interaction on the wood density (WD) of Eucalyptus planted in tropical environments in Brazil. Eucalyptus clones (R9: E. urophylla, B2: E. urophylla x E. grandis, H8, and D4: E. grandis x E. urophylla) were analyzed 4 years after planting at 10 sites. A total of 120 trees were sampled, and the WD was determined. The relationship between WD, mean annual increment, and climate variables (temperature, precipitation, vapor pressure deficit and soil water deficit) was assessed for each clone.

Results: The site effect and clone x site interaction were significant. Clones H8 and R9 showed the most consistent WD across sites, with density differences of 18 % and 14 %, respectively, and H8 exhibited a similar mean in 80 % of the sites. B2 and D4 were the most influenced by local growth with density variations of 28 and 22 %, respectively, indicating that WD is affected by the interaction of genotype and growth environment. Only B2 showed significant correlations between density and all environmental variables, while density in R9 did not correlate with any variable. Conclusion: Clones are similarly affected by climate across the tropical gradient of Brazil. However, the magnitude of responses differs among clones at a single site. The effects of climate conditions on density are more evident when contrasting situations are compared.

Keywords:
Tropical forestry, climate conditions, phenotypic plasticity, wood quality.

2- EMBRYOGENIC CALLUS INDUCTION FROM in vitro CULTURE OF MATURE ZYGOTIC EMBRYOS OF Euterpe edulis MARTIUS (ARECACEAE)

Victor Pereira Lago da Silva, Tsylla Assis Santos Ferreira, João Carlos Teixeira Fernandes, Ana Claudia Ferreira Cruz, Sérgio Yoshimitsu Motoike, Diego Ismael Rocha

Background: Euterpe edulis Martius, a symbolic species of the Atlantic Forest in Brazil, popularly known as the Juçara palm tree, does not produce axillary or basal shoots, which prevents its vegetative propagation through conventional techniques. Plant tissue culture techniques have been proposed for the clonal propagation of superior genotypes of this species. The present study aimed to evaluate the effect of 2,4-dichlorophenoxyacetic acid (2,4-D) on the induction of embryogenic calluses from mature zygotic embryos of E. edulis. Mature zygotic embryos were inoculated in culture media supplemented with different concentrations (20, 40, 80, 160, 320, 480, and 600 mg L⁻¹) of 2,4-D, while the control treatment contained no 2,4-D. The experiments were conducted in a completely randomized design.

Results: After 70 days in the induction medium, three morphogenic responses were observed: seedlings, abnormal seedlings, and calluses. Increasing concentrations of 2,4-D reduced the formation of normal seedlings while enhancing callogenesis up to concentrations between 160 and 279 mg L⁻¹. At higher concentrations, embryogenic calluses or oxidized explants predominated. Morphoanatomical evaluations confirmed the embryogenic identity of the calluses, which consisted of a meristematic center surrounded by a parenchymatic zone. Neutral polysaccharides and starch grains were mainly observed in the parenchymatic zone, which was not directly involved in somatic embryo regeneration.

Conclusion: This study demonstrates the formation of embryogenic calluses from in vitro cultures of zygotic embryos of Euterpe edulis. These findings contribute to the development of a complete regeneration protocol and may support the clonal propagation and conservation of this important Atlantic Forest palm species.

Keywords: Auxin, somatic embryogenesis, Juçara palm tree, plant regeneration, morphoanatomy.

3- PREDICTION OF Eucalyptus PRODUCTIVITY AND BASIC WOOD DENSITY USING A NOVEL WATER-AVAILABILITY-SENSITIVE PROXY

Aguinaldo José de Souza, Renata Guilherme Cândido da Silva, Leandro de Siqueira, Thayanne Caroline Castor Neto, Glaycianne Christine Vieira dos Santos Ataide, José Eduardo Macedo Pezzopane, Graziela Baptista Vidaurre

Abstract

Background: Water availability is a key driver of Eucalyptus productivity in tropical environments, yet traditional climatic indices often fail to adequately capture hydrological variability under humid conditions. This study evaluated how water availability, interacting with soil and management factors, influences productivity and basic wood density across contrasting tropical environments. Data from commercial Eucalyptus plantations across São Paulo, Bahia, and Maranhão were analyzed using multivariate regression models integrating climatic indices and a novel water-availability proxy (Log₁₀(AWAI)).

Results: The models showed high predictive performance (adjusted R² > 99%), with the proposed proxy exhibiting greater explanatory power in São Paulo and Maranhão. Basic wood density emerged as an integrative trait linking growth and environmental conditions: under humid climates, higher density was associated with increased biomass accumulation, whereas under drier conditions it reflected conservative strategies related to hydraulic safety. Additionally, clone HGU-1 demonstrated high ecophysiological plasticity and productive stability across contrasting environments.

Conclusion: The proposed proxy improves the representation of water availability in tropical conditions and supports more accurate water zoning, genetic material selection, and management strategies. These findings highlight the role of basic wood density as a functional indicator of the growth–safety trade-off in Eucalyptus plantations.

Keywords: Adaptive plasticity, forest ecophysiology, forest productivity, genotype-environment interaction, multivariate modeling

4- FOUR-DECADE ANALYSIS OF FIRE BEHAVIOR IN THE BRAZILIAN CAATINGA BIOME 1985-2023

Mauricio Alejandro Perea-Ardila

Abstract

Background: The Caatinga, unique in northeastern Brazil, has species adapted to the semi-arid climate. Recurrent fires put its biodiversity at risk, highlighting the need for urgent measures to protect this fragile ecosystem. This study analyzed four decades of fire behavior in the Caatinga biome (1985-2023) using data from the MapBiomas Fire project and spatial analysis, revealing an alarming increase in fire activity, which affected approximately 10.9 million hectares (≈12.74% of the biome). Results: Showed an increasing trend in the frequency and intensity of fires, with critical peaks between August and November, particularly in October where historical maximums were reached in the period 2015-2023 (48.1%). Spatial distribution showed significant concentrations in the western and southern regions of the biome, especially in the states of Bahia and Piauí, mainly linked to human activities. The temporal analysis revealed a progressive accumulation of burned areas, with a notable increase towards the end of the period studied. The recurrence of fires presented a heterogeneous distribution, with up to 39 events at the same point in critical areas, affecting mainly forest formations and herbaceous-bush vegetation.

Conclusion: The research underlines the vulnerability of the Caatinga ecosystem to these recurrent events, highlighting the urgent need to implement land management and fire management measures, including continuous monitoring programs and regional adaptive strategies that combine agricultural productivity with ecosystem conservation. This study contributes to the understanding of fire dynamics in tropical semiarid biomes, providing crucial information for decision-making in conservation and sustainable management policies.

Keywords: Burned area; Fires; Vegetation cover; Semiarid; MapBiomas.

5- EFFECTIVENESS OF DIRECT SEEDING TECHNIQUES FOR FOREST RESTORATION IN A BRAZILIAN CERRADO AREA

Paolo Alessandro Rodrigues Sartorelli, Andressa Ribeiro, Gabriel Marx Cordeiro, Mauricio Sangiogo, Kennedy de Paiva Porfírio, Antonio Carlos Ferraz Filho

Abstract

Background: Corymbia torelliana is a promising alternative for the forestry sector due to its rapid growth, resistance, and high-quality wood for charcoal and biomass production. However, there is limited information regarding its genetic performance under Brazilian conditions. This study aimed to estimate genetic parameters and evaluate correlations between growth traits in young half-sib progenies. The experiment was conducted in Lavras, MG, with 28 progenies evaluated in a randomized complete block design, with eight replications and five plants per plot. Height (H) and diameter at breast height (DBH) were measured at 12, 18, and 24 months, and genetic estimates were obtained using the REML/BLUP method, including analyses of genotypic and phenotypic correlations.

Results: Narrow-sense heritabilities showed moderate magnitude (0.18 to 0.22), as well as progeny selection accuracy (0.64 to 0.68). Individual genetic variation coefficients ranged from 8.3% to 12.8%, indicating genetic variability among individuals. The environmental effect among plots was significant, with a determination coefficient above 0.10. Average DBH ranged from 2.4 to 5.3 cm with increasing age, and mean height reached 2.91 m at 12 months. High genetic and phenotypic correlations suggest potential for simultaneous selection, although indirect selection accuracy was lower than direct selection.

Conclusion: The results confirm the genetic potential of C. torelliana for selective gains, particularly in DBH at 24 months. The study highlights the importance of improving management practices and selection strategies to mitigate environmental effects and enhance the accuracy of genetic estimates.

Keywords: Bacterial consortium, Cerrado restoration, climate change, forest inventory, native species.

6- BALANCING ACCURACY AND EFFICIENCY: OPTIMAL PLOT DESIGN FOR REGENERATION SAMPLING IN AMAZONIAN SECONDARY FORESTS

Bruno Barbosa Boás, Vitor Mateus de Carvalho Morais, Divino Vicente Silvério, Fabiano Emmert, Rodrigo Geroni Mendes Nascimento

Abstract

Background: Optimal sampling designs are crucial for accurate ecological and forestry assessments, particularly for regeneration studies in Amazonian secondary forests, which play an important role in biodiversity conservation and carbon sequestration. This study evaluated different sampling plot configurations for estimating regeneration diversity and structural attributes in a 30-year-old secondary forest in Belém, Brazil. Within a one-hectare permanent plot (100 × 100 m), all trees with a diameter at breast height (DBH) ≤ 10 cm were measured, identified, and geolocated, totaling 3,003 individuals. Trees were classified into two diameter classes: DBH < 5 cm and 5 cm ≤ DBH ≤ 10 cm. Resampling simulations using the bootstrap method subdivided the one-hectare plot into four sampling plot sizes (4 m², 25 m², 50 m², and 100 m²) with rectangular and square shapes. Simulations tested sample sizes ranging from four to (N − 1) units, with 1,000 iterations per configuration.Results: Accuracy and precision for diversity metrics (species richness and Shannon–Weaver index) and structural attributes (tree density, stem density, and basal area) were evaluated using Mean Absolute Error (MAE) and Relative Sampling Error (RSE). Results indicated that 4 m² sampling plots were the most suitable for estimating diversity metrics across both diameter classes, regardless of plot shape. For structural variables, square 4 m² plots performed best for trees with DBH < 5 cm, whereas rectangular 50 m² plots were optimal for trees with 5 cm ≤ DBH ≤ 10 cm. The influence of plot shape varied depending on the variable analyzed and the sampling plot size.Conclusion:Overall, sampling plots of 4 m² and 50 m² are recommended for efficient regeneration sampling in Amazonian secondary forests, as they provide better accuracy and precision for diversity and structural estimates across different diameter classes.

Keywords: Forest inventory, sampling simulation, urban forest, forest degradation

7- CARBON STOCK IN THE ABOVEGROUND VEGETATION OF REMEDIATED LAND QUARRIES IN NORTHWEST RUSSIA

Irina Alexandrovna Likhanova, Tatiana Alexandrovna Pristova, Aleksey Leonardovich Fedorkov, Olga Valerievna Shakhtarova

Abstract

Background: Forest recultivation can accelerate the formation of tree stand and increase carbon dioxide absorption. This study investigated the growth rates, biomass accumulation and carbon stock in stands of native Scots pine (Pinus sylvestris L.) (SP) and introduced lodgepole pine (Pinus contorta Dougl.) (LP) planted on remediated land quarries. A comparative analysis of the parameters is performed 1) in cultures using same planting material (bare-root SP seedlings) but developing on different parent materials (ancient alluvial sands, fluvioglacial sandy loams, and moraine loams) and 2) in pine cultures on the same deposits (fluvioglacial sandy loams), but using different planting materials: bare-root SP seedlings, container SP seedlings and container LP seedlings. Allometric equations were used to calculate stand biomass. The ground cover biomass was determined by the mowing method.

Results: Biometric parameters, biomass and carbon reserves, and the share of wood in the total biomass reserves increase along with the soil texture transformation from sands to silty loams. The aboveground biomass is dominated by mosses and lichens on sands to sandy loams and by herbaceous plants on loams. The LP cultures have better growth, survival, biomass and carbon stock values compared with those of the SP. In the quarries of the middle taiga subzone of Russia, 20-year-old experimental LP cultures accumulated 38% more carbon in the aboveground phytomass than SP cultures.

Conclusion: The soil conditions of quarries affect the growth and survival, biomass and carbon stock of pine crops. LP cultures outperformed SP cultures related to carbon storage on sandy loam substrates, highlighting its potential for recultivation in Northwest Russia.

Keywords: Biomass, forest recultivation, lodgepole pine, Scots pine, taiga.

8- LATENT COMPETITION AND THE INDIVIDUAL EFFECT OF MICROCLIMATIC VARIABLES ON STEM TREE GROWTH IN THE CENTRAL AMAZON

Luiz André Lima Pereira, Mikael Martins-Souza, Ricardo Antonio Marenco

Abstract

Background: Tropical forest dynamics are directly conditioned by microclimatic variations and resource competition, which modulate the development patterns of tree species. Despite their importance, there remains a significant scientific gap regarding the combined influence of these factors in high-density tropical forests where individual interactions may be masked. This study evaluates the individual effect of microclimatic variables and competitive status on the tree growth in diameter (TGD) of terra-firme species in Central Amazonia. The central hypothesis is that both microclimatic fluctuations and interspecific competition significantly and directly affect tree diameter increments.

Results: Growth of 33 trees from seven species was monitored over 48 months. To isolate the climatic impact from temporal trends, we used Principal Component Regression (PCR) and Principal Component Analysis (PCA). The average TGD was 0,15 mm month-1, with precipitation and soil water content (SWC) as the primary positive drivers for most species. Conversely, vapor pressure deficit (VPD) correlated negatively with growth rates. Regarding biotic factors, Moore’s index (Moore, et al. 1973) and four other tested indices showed no significant correlation with diameter. This high-density environment (338 stems/ha) suggests a condition where individual competitive effects are difficult to distinguish.

Conclusion: Tree growth in Central Amazonia is highly sensitive to water availability. The negative TGDVPD relationship suggests that atmospheric dryness is a limiting factor, potentially associated with adjustments in stomatal conductance. The findings support the hypothesis of “latent competition,” where high density masks the impact of specific competitors due to shared resource limitation. These results reinforce the vulnerability of tropical species to projected climate change.

Keywords: Vapor pressure deficit, soil water content, distance-dependent competition, dendrometer monitoring, terra-firme forest.

9- THE EFFECT OF CELLULOSE NANOCRYSTALS ON THE PROPERTIES OF Erythrina poeppigiana (WALP.) O.F. COOK PLYWOOD

Ricardo Gabriel de Almeida Mesquita, Mara Lúcia Agostini Valle, Daniel Piotto, José Benedito Guimarães Junior, Lourival Marin Mendes

Abstract

Background: Erythrina poeppigiana is a fast-growing, low density tropical wood species underutilized in southern Bahia, Brazil. Its plywood exhibits limited mechanical performance due to wide parenchyma bands, low lignin content, and high porosity. Cellulose nanocrystals (NCC) have been proposed as reinforcement to enhance panel stiffness and modify adhesive behavior. This study evaluated the effects of incorporating NCC into phenol-formaldehyde adhesive (PF) on the physical and mechanical properties of E. poeppigiana plywood.

Results: Plywood panels were produced with NCC loadings of 0, 1, 1.5, and 2% based on the total mass of the PF adhesive. NCC addition increased the parallel modulus of elasticity from 4651 MPa in the control to 6076 MPa at 2% NCC (≈31% increase), allowing the panels to reach the minimum requirement for concrete formwork plywood. No significant effect was observed on modulus of rupture. Water absorption and 24-hour thickness swelling increased with NCC, reflecting the hydrophilic nature of NCC and the wood’s anatomical structure. Shear strength decreased at higher NCC contents, particularly above 1%, likely due to increased adhesive viscosity and reduced spreading caused by NCC–polymer interactions. Other properties, including density and moisture content, remained unaffected.

Conclusion: NCC incorporation improved the stiffness of E. poeppigiana plywood; however, higher concentrations negatively affect bonding performance and moisture-related properties. The wood’s chemical and anatomical characteristics, notably broad parenchyma bands and low density, influence the overall performance. These findings suggest that controlled NCC incorporation offers a strategy to enhance value-added applications of underutilized species.

Keywords: Adhesive reinforcement, nanocellulose, tropical wood, wood anatomy, wood composites.

10- GENETIC PARAMETERS AND CORRELATION BETWEEN GROWTH TRAITS IN YOUNG PROGENIES OF Corymbia torelliana (F.MUELL.) KD HILL AND LAS JOHNSON

Gabriel de Resende Baroni, Adelson Lemes da Silva Júnior, Pedro Henrique Del Grossi, Adriene de Oliveira Bastos, Lavínia Barbosa Oliveira, Izabel Cristina Rodrigues de Figueiredo, Flávia Maria Avelar Gonçalves, Lucas Amaral de Melo

Abstract

Keywords: Forestry, forest breeding, heritability, indirect selection.