RESUMO Este trabalho teve como objetivo determinar a concentração de taninos condensados na casca da árvore Mimosa tenuiflora (Willd) Poir. Adicionalmente, foram avaliadas as propriedades físico-mecânicas de painéis de madeira laminada cruzada (MLC) colados com um adesivo à base de taninos de M. tenuiflora. A casca foi coletada de cinco árvores. A formulação adesiva foi sintetizada pela mistura de taninos em pó, paraformaldeído e água a 50°C sob agitação contínua. Extrato de taninos da casca em seu estado primitivo sem qualquer tratamento químico prévio ou modificação foi empregado para sintetizar o adesivo. Foram determinados a viscosidade, pH, teor de sólidos e tempo de gel da formulação adesiva. Os painéis foram fabricados com madeira de Eucalyptus spp. O desempenho de colagem foi avaliado determinando as propriedades físicas (densidade aparente e absorção de água) e mecânicas (módulo de elasticidade – MOE, módulo de ruptura – MOR e resistência ao cisalhamento) dos painéis de MLC. O teor de taninos condensados na casca de M. tenuiflora foi de 23,4%. As propriedades adesivas foram pH = 3,93, TS de 50,64%, tempo de gel de 460 s e viscosidade de 6.000 cP. Os valores de MOE, MOR e resistência ao cisalhamento foram 4.411, 16,18 e 1,06 MPa, respectivamente. Os taninos de M. tenuiflora são promissores para a formulação de adesivos para unir MLC.

ABSTRACT This study aimed to determine the concentration of condensed tannins in the bark of Mimosa tenuiflora (Willd) Poir trees. Additionally, the physical-mechanical properties of cross-laminated timber (CLT) panels bonded with an adhesive based on M. tenuiflora tannins were assessed. Bark was collected from five trees. The adhesive formulation was synthesized by mixing powdered tannins, paraformaldehyde, and water at 50 °C under continuous stirring. Bark tannins extract in its pristine state without any previous chemical treatment or modification was employed to synthesize the adhesive. Viscosity, pH, solids content, and gel time of the adhesive formulation were determined. CLT panels were manufactured with Eucalyptus spp. wood. The bonding performance was assessed by determining the physical (apparent density and water absorption) and mechanical (modulus of elasticity – MOE, modulus of rupture – MOR, and shear strength) properties of the CLT panels. Condensed tannins content in the M. tenuiflora bark was 23.4%. Adhesive properties were pH = 3.93, TS of 50.64%, gel time of 460 s, and 6,000 cP for viscosity. Values of MOE, MOR and shear strength were 4,411, 16.18, and 1.06 MPa, respectively. The M. tenuiflora tannins are promising for the formulation of adhesives to bond CLT.

ABSTRACT Background: Neotropical species lack autecological information. Among these, are phenological studies, which help to understand forest dynamics and provide important contributions to the collection, restoration, and conservation programs. This research aimed to characterize the vegetative and reproductive phenological behavior of neotropical species Geoffroea spinosa Jacq. in a seasonally dry tropical forest, as well as to verify if there is a correlation between phenophases and environmental parameters. Twenty individuals were accompanied monthly for two years, to detect and tally the presence of floral buds, flowers, immature fruits, ripe fruits, leaf emergence, presence of mature leaves, and defoliation. A semi-quantitative evaluation was carried out with the Fournier method. Results: The results showed that the population had synchrony of reproductive events, with more than 50% of the individuals blooming and fruiting during the same time interval. Furthermore, the circular statistical test indicated a high seasonality for reproductive events (r ≥ 0.50 and p < 0.001). Among the vegetative events, all were classified as non-seasonal (r < 0.5). G. spinosa, showed a significant correlation (p ≤ 0.05) for all meteorological variables evaluated. Conclusion: The reproductive phenophases of G. spinosa showed strongly seasonal behavior, unlike vegetative events. the period between mid-February and the end of March was the most propitious for fruit collection. No seasonality was observed for the vegetative events. The species proved to be sensitive to El niño conditions. Follow-up phenological studies associated with meteorological variables are important for a better understanding of the dynamics of vegetative behavior in response to climate change.