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ABSTRACT Nutrient prediction models applied to tree species from Brazilian Caatinga can be a crucial tool in understanding this biome. The study aimed to fit a mixed model to predict nitrogen (N), phosphorus (P), and potassium (K) content in tree species native to the Caatinga biome located in Floresta municipality, Pernambuco State – PE, Brazil. The following species were considered the area’s most important and evaluated in the present study: Poincianella bracteosa (Tul.) L.P.Queiroz, Mimosa ophtalmocentra Mart. ex Benth, Aspidosperma pyrifolium Mart, Cnidoscolus quercifolius (Mull. Arg.) Pax. & Hoffm, and Anadenanthera colubrina var. cebil (Griseb.) Altschul. Four trees, representing the average circumference in each diameter class, were harvested for NPK quantification. The Spurr model was evaluated for NPK prediction, and species inclusion as a random effect was significant (p > 0.05) in all models. The Spurr model with fixed and random effects presented better statistics than fixed-effect models in all parameters for all nutrients. Generated NPK predicting equations can be a handy tool to understand the impact of wood extraction over Caatinga’s biogeochemical cycles and guide forest management strategies in semi-arid regions of the world. RESUMO Modelos de predição de nutrientes aplicados a espécies arbóreas da Caatinga brasileira podem ser uma ferramenta crucial para a compreensão do bioma. O estudo teve como objetivo ajustar um modelo misto para prever os teores de nitrogênio (N), fósforo (P) e potássio (K) em espécies arbóreas nativas do bioma Caatinga localizadas no município de Floresta, Pernambuco – PE, Brasil. As seguintes espécies foram as mais importantes da área e avaliadas no presente estudo: Poincianella bracteosa (Tul.) L.P.Queiroz, Mimosa ophtalmocentra Mart. ex Benth, Aspidosperma pyrifolium Mart, Cnidoscolus quercifolius (Mull. Arg.) Pax. & Hoffm e Anadenanthera colubrina var. cebil (Griseb.) Altschul. Quatro árvores, representando a circunferência média em cada classe de diâmetro, foram colhidas para quantificação de NPK. O modelo Spurr foi avaliado para predição de NPK e a inclusão de espécies como efeito aleatório foi significativa (p > 0,05) em todos os modelos. O modelo de Spurr com efeitos fixos e aleatórios apresentou estatísticas melhores que os modelos de efeito fixo em todos os parâmetros para todos os nutrientes. As equações de previsão de NPK geradas podem ser uma ferramenta útil para entender o impacto da extração de madeira sobre os ciclos biogeoquímicos da Caatinga e orientar estratégias de manejo florestal em regiões semiáridas do mundo.

ABSTRACT The use of forest seedling banks is recommended for producing seedlings of species essential for specific forest typologies for which propagation poses challenges. However, given the lack of understanding of how human intervention, such as the removal of regenerating individuals from the forest, influences the composition and structure of the plant community, there is a pressing need for further research. Our primary objective here was to identify the effects of seedling removal on natural regeneration in forest communities and to characterize seedling bank dynamics three years after anthropogenic intervention. A randomized block design was used for the experiment, consisting of five removal intensities (0, 25, 50, 75, and 100% removal), with evaluations conducted every three months for three years. All individuals of the shrub-arboreal component between 5-55 cm heights were measured. Collected data were analyzed to determine the impacts of the removal of individuals and the influence of environmental elements on the seedling community. We found that the shrub-arboreal component of the forest community exhibited marked resilience three years following the removal of regenerating individuals. Removal of up to 50% of regenerating individuals does not appear to interfere with plant community dynamics, suggesting species with a high density of individuals in the seedling bank are resilient to the impacts of human intervention. Although climatic seasonality also affects seedling bank dynamics in plant communities, this effect depends on the level of human intervention in an area and, therefore, has been omitted from the analysis.

ABSTRACT Mistletoe is an important nutritional resource for the frugivorous ornithological fauna in several ecosystems. However, in great intensity, they can reduce the vigor of their host trees, requiring adequate management in urban afforestation, without depleting this source of food for birds. The hypothesis that there are hemiparasites with host specificity was the reason for this study. Thus, a floristic census of the trees was carried out at UFMT, campus Cuiabá; the infestation by genus of hemiparasite present was recorded, in quantity and degree of infestation, in addition to the quantification of seeds of the hemiparasite germinated without the development of the vegetative part, whose cotyledons necrotized and died. A total of 4265 tree individuals were evaluated, distributed in 46 families, in which 16,52% were identified of the genera Phoradendron, Psittacanthus, and Struthanthus, of which about 90,0% were Psittacanthus. The highest infestation occurred in 24 families, highlighting Fabaceae (28,3%) and Combretaceae (25,6%), and the species Terminalia catappa, Anadenanthera peregrina, and Vatairea macrocarpa. The presence of germinated seeds of the hemiparasite with dead cotyledons varies between tree species and between individuals of the same species. The highlight was in Rutaceae, Arecaceae, and Rubiaceae, and in the species Acrocomia aculeata, Caryocar villosum, and Genipa americana L. that present individuals with natural control potential, even with the presence of frugivorous ornithological fauna and the dispersion of the hemiparasite. In general, the intensity and degree of infestation are low, and there is no infestation in the Caryocaceae, Rutaceae, and Rubiaceae families, highlighting the species Caryocar villosum, Murraya paniculata and Alibertia edulis.

ABSTRACT Glued Laminated Timber technology allows the construction of wooden structural components bonded with adhesive. This technology enables the creation of large-scale structures, with technological control over the material, and in a competitive industrial system. Focusing on the structural application of wood, the present study assessed the strength of bonded joints with different angles between the fibers of Pinus sp. wood, joined with a two-component polyurethane adhesive based on vegetable oils. The bonded joints were fabricated with angles of 0°, 10°, 20°, 30°, 45°, 60°, 70°, 80°, and 90°, and were evaluated for shear strength under compression and torsion. When regression analysis was performed, shear compression values showed compliance with Hankinson’s equation, with an R2 value close to 0.76. However, shear torsion results yielded R2 values near 0.17. Thus, Hankinson’s equation was unsuitable as an estimator for torsional shear strength values. The specimens showed a different mechanical response to shear when tested in compression compared to those tested in torsion.

ABSTRACT The main function of the adhesive is to promote adhesion between materials, as well as provide fluidity and fill in the gaps between joints. Information such as grammage and bonding pressure is fundamental when it comes to the execution of structures in glued laminated wood. In this sense, the objective of this study was to evaluate the shear strength in compression of bonded joints using a one-component polyurethane adhesive with cold curing at three different gram levels, being 150 g.m-2, 200 g.m-2 and 250 g.m-2, with spreading on a single face, applied at two pressure levels, 0.7 MPa, and 1.0 MPa. The apparent density was determined, and with that, four blocks/density groups were obtained, which comprised four repetitions. In addition, the percentage of failure in the specimens after performing the shear test was analyzed. Statistical data analysis was carried out adopting a randomized design in a 2x3 factorial block to analyze the effects of grammage and bonding pressure on wood strength and failure The homogeneity and normality of the data were tested, and later the analysis of variance (ANOVA). The results showed that the joints’ strength was not affected, both for weight and pressure levels. As for the wood failure percentage, the values obtained were low, with averages below 35%.

ABSTRACT Phenology is defined as the study of the timing of biological events and the biotic and abiotic factors that trigger them. This study reports a description of the phenology of Byrsonima pachyphylla and B. verbascifolia in an ecotonal area between the Cerrado and Amazonia biomes in the Brazilian state of Tocantins, to contribute to a better understanding of their autoecology in this region. Two populations of 15 adult individuals of each species, randomly selected in a Cerrado area in Porto Nacional, Tocantins, were surveyed for 12 months. Percentages were estimated of leaf flush, young, mature, and senescent leaves (vegetative phenology), flower buds, open flowers, green and ripe fruits (reproductive phenology) present in the canopy, as well as the synchrony of the reproductive phenophases. The vegetative and reproductive phenological events were seasonal and occurred mainly at the end of the dry season and during the transition from the dry to the rainy season. Considering the vegetative and reproductive phenology, B. pachyphylla was classified as “evergreen with continuous growth” and as a late-flowering species, whereas B. verbascifolia was classified as “evergreen with seasonal growth” and as an early-flowering species. The reproductive phenological activity of the species exhibited high synchrony. The results suggest that the vegetative and reproductive events are peculiar to each species and represent effective strategies for their survival in the Cerrado, which is markedly seasonal.

ABSTRACT When producing Ilex paraguariensis seedlings through vegetative propagation, selecting the correct populations and genotypes, and obtaining juvenile material, may be fundamental for its success. Therefore, this search aimed to test its vegetative propagation through cutting and rescue using detached branches of different populations in Santa Catarina state, Brazil. Thus, two experiments were installed in September 2019 in order to test: I) the cuttings of four populations belonging to the municipalities of Catanduvas (CT), Painel (PL), Três Barras (TB), and Urupema (UR), using ten randomly chosen genotypes from each, and; II) the epicormic sprouting of detached branches from these same populations. Both experiments were carried out in Lages, Santa Catarina. In February 2020, the cutting was evaluated according to the percentages of survival, callus, rooting, new sprouts, and original leaves permanence. The branches were evaluated every 30 days after storing, observing the percentages of sprouting branches, number of sprouts, and length of sprouts in centimeters. As for cutting, there was a low survival percentage in all populations (<15%), but some genotypes presented greater vigor, such as TB1 (46%), TB7, and TB3 (both 28%). Most live cuttings presented calluses (>70%), characteristic of material of high maturity. Rooting was low for populations (<1.5%) and genotypes (<10%). Branches presented sprouts up to 60 days, with TB presenting the highest total number of sprouts (approximately 300) and the greatest average length (2.8 cm). In general, survival and rooting of cuttings were affected by both populations and genotypes, highlighting TB. A similar response was observed for the branches’ sprouting. New studies with more populations, further analyses of the branches’ characteristics, and better storage conditions are recommended.

ABSTRACT To simplify the characterization of wood species, the Brazilian standard document ABNT NBR 7190-1 (2022) establishes the determination of mechanical properties employing the characteristic strength in the compression parallel to grain (fc0,k). This mechanical property is estimated using the linear relation given by the following expression fv0,k = 0.12·fc0,k Brazilian and European standard documents support the estimation of fv0,k using relations among properties. However, the European guidelines in the EN 384 (2019) have used the conventional characteristic strength in the static bending test (fM,k). Thus, this study aimed to investigate the efficiency of the ratio fv0,k = 0.12·fc0,k for adopting 30 hardwoods. The variance analysis results demonstrate the divergence among the experimental outcomes and those values estimated using the relation cited. Therefore, regression models at two parameters were considered to obtain more accurate estimates of fv0,k by adopting fc0,k, and fM,k as independent variables. Regarding the results, the geometric (R² = 80.80%) and linear (R² = 74.19%) models were the most accurate for the estimates of fv0,k in terms of fc0,k, and fM,k, respectively. This fact evinces the good accuracy of the models under consideration, which may provide a more rigorous structural design compared to the correlation currently prescribed by the ABNT NBR 7190-1 (2022). RESUMO Para simplificar a caracterização de espécies de madeira, o documento normativo brasileiro ABNT NBR 7190-1 (2022) estabelece a determinação de propriedades mecânicas por meio da resistência característica na compressão paralela às fibras (fc0,k). Essa propriedade mecânica é estimada utilizando-se da relação linear dada pela expressão a seguir fv0,k = 0.12·fc0,k. Ambos os documentos normativos europeu e brasileiro prescrevem a estimativa da fv0,k empregando-se relações entre propriedades, embora as diretrizes da europeia contidas na EN 384 (2019) utilize a resistência característica convencional obtida no teste de flexão estática (fM,k). Assim, esse estudo teve o objetivo de investigar a eficiência da relação fv0,k = 0.12·fc0,k para 30 espécies folhosas. Os resultados da análise de variância demonstram a divergência entre os resultados experimentais e aqueles estimados utilizando-se da relação citada. Portanto, modelos de regressão em função de dois parâmetros foram considerados para se obter estimativas mais precisas da fv0,k através da adoção da fc0,k e fM,k como variáveis independentes. Com relação aos resultados, os modelos geométrico (R² = 80.80%) e linear (R² = 74.19%) foram os mais precisos para a estimativa da fv0,k em termos da fc0,k e fM,k, respectivamente. Este fato evidencia a boa precisão dos modelos em questão, o que pode proporcionar um dimensionamento estrutural mais rigoroso quando comparado à correlação atualmente prescrita pela ABNT NBR 7190-1 (2022).