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ABSTRACT Background: Today, the biggest threat to mammalian predators with wide distribution areas is habitats fragmentation or changing climate conditions. We aimed to reveal the habitat suitability modeling and mapping of the Brown bear, which is an important large mammal in Turkey’s borders, under change climate. The habitat suitability modelling was determined using the present (2010) and future (2040-2070-2100) chelsa climate scenarios (IPSL-CM6A-LR SSP126-SSP370-SSP585) Maxent method with the present data obtained by examining all studies on Brown bear. Then, the mapping result values for the different years and scenarios were classified as 0.5 unsuitable habitats, 0.51-0.8 suitable habitats and 0.81-1.0 most suitable habitats. Results: We determined that the variables contributing to the habitat suitability model of Brown bear are annual precipitation amount, the average annual air temperature, the precipitation amount of the wettest month, the ruggedness and elevation. According to the mapping results for different years and scenarios; Brown bear have suitable habitat a minimum of 14.87% of the study area in today, 12.56% in 2040 year, 10.93% in 2070 year and 8.24% in 2100 year. According to the SSP585 climate scenario of 2100 year, the habitat suitability of the Brown bear decreases by approximately 45%. Also, the climate envelope model created with MaxEnt revealed, the change climate in the 2100 year endangered the Brown bear. Conclusion: Therefore, these results will be a source of information for the sustainability of the extinction of the Brown bear, for the pre-protection of existing and potential habitats and for reducing the impact of change climate conditions.

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ABSTRACT Background: Climate change, which has mainly manifested in Iran in the form of intensifying periods of drought, can have profound effects on the valuable forest ecosystems of Zagros in the west of Iran. In this study, the drought trend in the period from 2000 to 2020 was investigated on the spatio-temporal dynamics of greenness of Zagros oak forests in Kohgiluyeh and Boyer Ahmad province in the west of Iran. SPI, PDSI, NDVI and EVI with modeling their relationship based on GWR was used. Also, based on two climate change scenarios RCP2.6 and RCP8.5, the simulation of drought conditions and changes in forest greenness until 2050 were studied. Results: The results showed that the peak greenness of the oak forests has a significant sensitivity to changes in rainfall and drought at the end of the cold period of the year and in the spring season. The negative phases of the drought have been completely consistent with the periods of greenness loss. Also, both the greenness and the area of ​​the oak forests have decreased. The EVI index showed the highest sensitivity to the PDSI, and the developed model based on these two indices had a spatial explanation coefficient between 40 and 70%. Conclusion: The implementation of the developed model under two scenarios showed that the forest greenness will face a decrease of about 25% in the RCP8.5 scenario and about 15% in the RCP2.6 scenario until 2050. The relationship between drought and forest decline was proven in this study.

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ABSTRACT Background: Bamboo species have a high potential to produce biomass and stock carbon. However, biometric tools are not available to estimate biomass production for most giant bamboo taxa. The aim was to develop an additive equation system to estimate the aboveground biomass by structural component and the total of the three bamboo species. Destructive sampling was applied, and a sample of 101 mature bamboo specimens was collected. The nonlinear power allometric model was used to integrate two additive equations systems, which were formed by the structural components of biomass: culm, branches and leaves as well as aboveground biomass total. The predictor variables were: diameter at breast height (D) for the S1 system, and D in combination with the total height (D2H) for the S2 system. Results: It was determined that the SUR method in combination with the dummy variables technique and the correction of heteroscedasticity is an adequate fit strategy. Given that the additivity property is fulfilled, specific values of the parameters of each system and by taxon are identified. In addition, the variance of the error stabilizes. The aboveground biomass of the culm constitutes 86.40%, 90.48%, and 93.94% for Bambusa oldhamii Munro, Guadua aculeata Rupr., and Guadua angustifolia Kunth, respectively. The S1 system was selected, and its statistics regarding the total aboveground biomass were 0.92, 4.9 kg, -0.35 kg, and 0.05 for the fit statistics R 2 adj , RMSE, S, and E, respectively. Conclusion: This biometric tool will easier to carry out aboveground biomass inventories, as well as to infer the carbon content and CO2 equivalent at the specimen level.

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ABSTRACT Background: Vegetation indices have recently been proposed for remote sensing SAR (synthetic aperture radar) sensor measurements to monitor vegetation. However, they still lack validation studies on different vegetation types for their correct application. Thus, the objective of this study was to test the applicability of the Dual-polarization SAR Vegetation Index (DPSVI) and the modified DPSVI (DPSVIm) as indicators of aboveground biomass (AGB) from dense forest fragments. Results: Three forest fragments, comprising 54 forest plots with AGB ranging from 12 up to 220 Mg ha-1, were studied. These forest fragments belong to the Brazilian Atlantic Forest biome, and were located within the Doce river hydrographic basin in the state of Minas Gerais, Brazil. AGB was compared with the DPSVI and DPSVIm indices, computed from dual-polarization Sentinel-1 images, using Spearman’s rank correlation test through two approaches. In the first approach (A1), correlation tests were performed using all forest plots; in the second approach (A2), samples were taken from plots on flat to undulating terrain slopes. The correlation of AGB with DPSVI presented no significant correlation (p-value >> 0.05). In contrast, for DPSVIm, the correlation with AGB was significant and positive, with coefficients ranging from 0.4 in approach A1 to 0.7 in approach A2. Conclusion: While the DPSVI index did not show a correlation with the AGB of the studied forests, even though it is a C-band index, the DPSVIm was found to be a good indicator of the amount of AGB in forests and therefore has potential for applications in future studies, particularly in areas with reasonable slope or flat terrain.

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ABSTRACT Background: The objective of this study was to detect native trees from different flight configurations and smoothing techniques in Canopy Height Models (CHMs) in a native remnant in the municipality of Curitiba, State of Paraná, Brazil. To do so, eight flights were carried out with a Phantom 4, with two flight planning applications (Litchi and Pix4Dcapture) and two flight arrangements (single and double), totaling four flights for each application. All flights were processed using the Pix4Dmapper program. The LiDAR database was obtained with a DJI Matrice 300 system and from this data, the Digital Terrain Model (DTM) of the area was extracted. From the UAV data, the Digital Surface Model (DSM) of each flight was obtained. Subtracting each DSM from the DTM resulted in the CHMs for each UAV flight flown. The CHMs were smoothed with the CHMsmoothing function and three search window sizes were tested (6.5 x 6.5, 8 x 8, and 10 x 10). Results: The results of the ITD approach revealed that in unsmoothed and smoothed CHMs, the search window of size 8 resulted in the best precision metrics, with the highest recall, precision, and F-score values. In the smallest window size, there was the highest number of false positives while in the largest window size, the omitted trees were more representative. Conclusion: The best combination between flight parameters and smoothing techniques was with the Litchi application, with a single flight and 80% lateral and longitudinal overlap, resulting in individuals detected with an F-score of 0.94.

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ABSTRACT Background: The insertion of stand variables allows for generalized mixed-effects height-diameter model, and the inclusion of random effects aids in model flexibility and application to new databases through calibration. This study aimed to develop a generalized mixed-effects model capable of accurately predicting the total height of Pinus taeda trees, subjected to different management regimes and at different ages. Results: Experimental data between 4 and 27 years of age collected from stands of Pinus taeda located in the State of Santa Catarina were used. The experiment covers a combination of different planting densities and thinning intensities. The Lasso method was used to select the model’s independent variables, and mixed modeling was implemented, with calibration using BLUP (best linear unbiased predictor). Dominant height and quadratic mean diameter were selected in different formulations by the Lasso method to compose the predictor variables of the model, along with diameter at 1.3 m (dbh). Random effects were entered into the intercept and inverse of dbh terms of the model. Conclusion: The results show that the generalized model developed presents flexibility and can be applied to Pinus taeda stands in southern Brazil using the calibration of random effects, when necessary, by collecting a small sample of plot data.

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ABSTRACT Background: Extensive research seeks to improve forest management by understanding the effects of silvicultural treatments on productivity. Continuous forest inventory (CFI) plots offer valuable data for such studies. However, accuracy relies heavily on the twin plot concept, where two adjacent plots (twins) are established to isolate treatment effects from natural variation. This study explored the validity of the twin plot concept by analyzing data from 191 plot pairs in clonal eucalypt plantations. Specifically, it aimed to assess the equality of production volume and the internal structure between CFI plots and their twin plots. Results: Normality assumptions for plot volume differences were not met, even after applying a transformation procedure. Paired t-tests couldn’t be performed, but the non-parametric Wilcoxon test indicated no statistical difference in plot volumes. However, a different procedure called the L&O test revealed significant statistical differences. Gini coefficients demonstrated variations in tree volume distribution between plot pairs. Limited tree numbers and varying diameter classes prevented the use of Chi-square tests for diameter distribution equality. The Kolmogorov-Smirnov test showed non-adherence to estimated distributions using the Weibull distribution function. The L&O test identified significant differences in diameter distributions in 55 of the 191 plot pairs. Conclusions: We have concluded that it is critical to determine the twin nature of plots during first tree measurement to properly analyze the effects of silvicultural treatments on forest productivity. This requires robust statistical tests, adherence to assumptions, examination of internal plot structures, and adequate plot sizes for modeling diameter distribution.

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ABSTRACT Background: This study reveals the surprising impact of large trees on biomass modeling and estimation in tropical forests. Findings emerged from viewing tropical forests as an Extremistan environment-a domain where a small number of extreme events disproportionately impact overall outcomes. The aims were to: (i) determine whether humid tropical forests can be characterized as an Extremistan environment, (ii) quantify the impact of large trees on the biomass quantification, and (iii) recommend better practices to mitigate the impact of large trees. The methods included forest simulation, biomass model calibrated with multi datasets and extensive examination of the impact of large trees on model performance and mean biomass estimation. Results: The select group of the 1% heaviest trees account for 25-35% of the total biomass, a concentration analogous to the wealth concentration in developed countries. Additionally, a “tyranny” of the 5% heaviest trees (diameter >18-31 cm) was observed, in which 50-75% of the total biomass is retained, significantly affecting biomass modeling and mean biomass estimation regardless of the model used. Conclusions: This study confirms that humid tropical forests behave as an Extremistan environment. For biomass and carbon inventories, installing 10,000-m² sample units is recommended to mitigate the “tyranny” effect of the 5% heaviest trees, with a minimum size threshold of 4000 m².

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ABSTRACT Background: Hancornia speciosa is a species known for its medicinal and nutritional properties. Despite being a plant native to several regions of Brazil, some aspects of its production system are not yet well defined. Large-scale asexual propagation stands out, making it difficult to establish commercial orchards with materials with superior characteristics. In this context, this article aimed to investigate the scientific production related to the propagation and conservation of the mangabeira, using a mixed methodology of bibliometric analysis and literature review. The Scopus and Web of Science databases were consulted and the VOSviewer software was used to map the cooperation network between authors, institutions, and keywords. Results: The study included 72 articles and found a significant increase in scientific production on mangabeira propagation and conservation since 2009. Most studies focused on seed technology, seedling production, in vitro propagation and conservation, and cryopreservation. Additionally, it was observed that mangabeira seeds do not tolerate a reduction in moisture content, and the combination of materials for the composition of the substrate, such as coconut fiber, manure, and sand, can provide an adequate basis for developing seedlings. It was also observed that MS culture medium, complete or with half saline concentration, or WPM medium can be used for in vitro germination and initial seedling growth. Conclusion: Through this review, we concluded that the mangabeira presents substantial potential for the development of innovative propagation techniques, with a special focus on methods that facilitate the clonal propagation of the species, such as grafting, rooting cuttings, and micropropagation. It is expected that future research will expand knowledge about the in vitro and ex vitro propagation of this species, contributing to the expansion of commercial plantations with a focus on adding to the processing of its fruits.

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ABSTRACT Background: The objective of this study is to characterize the diversity and genetic structure of A. colubrina in three Atlantic Forest fragments in the south of Espírito Santo state, using Inter Simple Sequence Repeats (ISSR) molecular markers. Genomic DNA from 85 trees was analyzed using 12 ISSR primers, generating 147 fragments, of which 109 were polymorphic (74%). Markers were characterized as moderately informative, with a mean polymorphic informational content of 0.34. Results: Low genetic diversity was found for the three fragments and in the total sample, based on Nei’s diversity parameters (H* = 0.26) and Shannon’s index (I* = 0.38). In the dissimilarity analysis, four groups were observed in the dendrogram with an exclusive clustering trend by location. The analysis of molecular variance confirmed that most of the genetic variation is found within populations (73.50%), however, with high genetic differentiation between them (Φ ST = 0.26). This result was supported by the Bayesian approach that indicated genetically structured populations. Conclusion: The data obtained reveal that forest fragmentation affected the diversity and genetic structure of A. colubrina and allow expanding knowledge for the development of effective strategies for the conservation and management of the species.

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ABSTRACT Background: The objective of this study was to evaluate the quality indicators for wood and charcoal from the Eucalyptus urophylla x Eucalyptus grandis hybrid (Clone GG 100) in different planting spacings. The study was conducted with the hybrid using the spacings of 2×1, 2×2, 3×2, and 3×3 m. The chemical properties of wood and charcoal were analyzed, and dry wood mass and energy per hectare were estimated. The data were subjected to the t test for comparison of means. Moreover, principal component analysis was conducted to assess the relationships between wood and charcoal indicators as a function of spacing. Results: The 2×2 m spacing showed the highest values for dry wood mass, lignin mass, mass of charcoal, and energy. The wider spacings of 3×2 and 3×3 m resulted in wood and charcoal of increased quality by showing wood of greater resistance to thermal degradation and charcoal of higher yield. Conclusion: Spacing between trees influenced wood quality indicators. The 2×2 m spacing showed higher estimates of mass and energy per hectare. However, wide spacings with an area greater than 6 m2 are more suitable for charcoal production due to their superior wood properties, especially basic density and total lignin, which influence gravimetric yields and bulk density.

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ABSTRACT Backgrounds: Urban and peri-urban fragments are vital for biodiversity conservation, requiring genetic assessment of tree species in fragmented forests. The aim of this study was to analyze the genetic variability and diversity for adult individuals of J. micrantha along an urban-rural gradient in the Araucaria Forest. Fifteen individuals were sampled, with five from each remaining forest type. Initially, 10 ISRR primers were tested. Five mother trees were chosen from each site (urban, peri-urban, and rural) with a minimum distance of 100 m. The experimental design was a RCBD with 15 progenies, three provenances, three blocks, and 20 plants per plot, totaling 900 seedlings. Results: The average percentage of polymorphic loci was 93.33%. The urban population showed a greater loss of genetic diversity (H=0.1806). 79% of the genetic diversity was found within populations. The observed gene flow value (Nm) was 1.8790, indicating that there were no random losses of alleles within populations. The fragments did not exhibit significant differences, but there were significant differences among the progenies. The stem diameter (SD) and the height-diameter relationship (H/SD) emerged as the key traits for selecting new individuals due to their higher heritability (< 0.50), accuracy (< 0.70), and relative coefficient of variation (< 7%). Conclusion: The urban fragment is the most affected, but gene flow between fragments prevents the random loss of alleles. The analysis suggests that these fragments form a unique population, despite geographic barriers. Thus, the three fragments can be considered when choosing superior individuals for future progeny tests in genetic improvement programs for the species.

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ABSTRACT Background: Eucalyptus globulus Labill. is a species of great interest to the pulp industry. However, it has a low rooting capacity, which makes it difficult to clone on a commercial scale. In micropropagation, the supply of cytokinins is necessary to stimulate proliferation, but the type and concentration of cytokinins can negatively affect adventitious rooting. This study evaluated the effect of metatopoline (mT) and benzyladenine (BA) on in vitro multiplication, elongation, and rooting of E. globulus clones. In the multiplication medium, concentrations of 0.44 and 0.88 µmol BA, 0.41 and 0.83 µmol mT, and a control medium without cytokinins were supplied. Results: During the multiplication phase, mT increased the proliferation rate. In addition, mT presented lower production of small explants, less than 0.5 cm in height. In the rooting phase, easy rooting clones treated with 0.41 µmol of mT reached rooting percentages of 91%, while with the use of BA it was 50%. However, in clones with difficult rooting, no differences were observed in relation to the type of cytokinin. Explants treated with mT developed longer roots than those originated with BA, which presented roots similar to those of the control treatment (T). Conclusion: With the use of mT in the multiplication medium, the in vitro elongation, proliferation and rooting of E. globulus was improved, therefore improving the quality of the in vitro explants for the acclimatization stage.

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ABSTRACT Background: The determination of seed moisture content is of utmost importance for the evaluation of its quality. Near-infrared (NIR) spectroscopy has been successfully applied to estimate properties of biological materials. However, studies using this technique on forest seeds are still scarce. Thus, the aim of this study was to explore the potential of NIR spectroscopy for estimating the moisture content of E. uniflora seeds. NIR spectra were obtained using optical fiber from 100 individual seeds that were dehydrated in silica gel for 2, 7, 14, and 21 days. Subsequently, the seeds were subjected to the moisture test by the oven method, and had moisture contents of 52.4%, 41.7%, 33.1%, 21.8%, and 18.1%, respectively. Results: Principal component analysis (PCA) of the spectral signatures explained 100% of the data variability. The moisture content was associated with the spectra by partial least squares regression (PLS-R) and the predictive model presented a coefficient of determination in cross-validation (R²cv) of 0.88 and the root mean square error of cross-validation (RMSEcv) was 5.43%. Conclusion: The statistics associated with the models indicate that NIR spectroscopy has potential for estimating the moisture content of E. uniflora seeds.

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ABSTRACT Background: The water deficit characteristic of semi-arid regions can cause negative changes in plant physiology. Arbuscular mycorrhizal fungi can meet water needs by associating with plant roots, improving seedling quality. The physiological parameters and the quality of the seedlings of Parkia platycephala Benth. were evaluated as a result of the association of isolated strains of Gigaspora rosea, Gigaspora margarita, Acaulospora koskei, Acaulospora morrowiae, intercalated strains (a mixture of the four strains mentioned above) and a control (without inoculation) under two conditions of water regime (with and without stress). Results: Artificial inoculation of AMF is a promising management technique in the production of P. platycephala Benth seedlings for improving the physiological state, increasing seedling quality, and drought resilience. Under restriction water restriction conditions, the seedlings showed lower values of net CO2 assimilation, leaf transpiration, stomatal conductance, and higher values of internal CO2 concentration. Under these conditions, the G. rosea strain stood out with the lowest rate of net CO2 assimilation (A), leaf transpiration (E), and stomatal conductance (gs) with increases of 34, 49, and 70 %, respectively, compared to the control. Conclusion: Stomatal closure is a strategy used by Parkia platycephala Benth. seedlings to prevent excessive water loss, and the Gigaspora rosea strain is responsible for mediating the best physiological conditions and better quality seedlings.

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ABSTRACT Background: The present study verified the effect of controlled-release fertilizer (CRF) doses combined with tube volumes on the initial growth of seedlings of Khaya anthotheca and Khaya grandifoliola, through evaluations of morphological, physiological, and nutritional characteristics. The experiment was conducted in a factorial arrangement (5 × 2), evaluating the interaction of five concentrations of 15-9-12 CRF and two tube volumes. After 180 days, the morphological parameters of the seedlings were evaluated. Samples of the aboveground and root parts were collected for determination of macronutrients and organic carbon. Results: Regarding the interaction dose × container volume, for all evaluated characteristics, K. anthotheca and K. grandifoliola seedlings grown in substrate without the addition of CRF showed the lowest means, while seedlings with higher doses resulted in statistically superior responses for the studied attributes. The multivariate analysis of principal components, concerning the nutrients present in the leaves and roots of K. anthotheca and K. grandifoliola, allowed for characterizing the groups of nutritional similarities between the CRF doses and the volume of the tubes. Conclusion: The different doses of CRF resulted in significant variations in the growth of K. anthotheca and K. grandifoliola seedlings, with the application of the 10 g L-1 dose of CRF recommended for both species. The volume of the tubes did not show disparities in the morphological growth characteristics analyzed in the studied species, highlighting the Dickson Quality Index as one of the most accurate measures. The volume of 280 cm³ stood out, indicating seedlings of better quality.

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ABSTRACT Background: The restricted dispersibility of cellulose in water has grown to be a significant problem which is a key step in making cellulose soluble in water and common solvent. To overcome the obstacle, cellulose structure is being modified to improve the surface properties and the utilization of the cellulose itself. In this study, cellulose I and cellulose II were examined after treated with water-soluble 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO). The hydrogen bond between chains and the crystallinity of the cotton linter (cellulose I) was first broken by NaOH/urea. Then, cellulose I and NaOH/urea-treated cellulose (cellulose II) were oxidized with sodium chlorite, sodium bromide, and TEMPO in a catalytic amount. Results: The success of oxidation is achieved when both cellulose I and II treated with TEMPO had preferentially converted the hydroxyl groups to carboxylate groups through Fourier Transform Infrared Spectrometer (FTIR). Besides, through X-ray diffraction analysis, cellulose I and II exhibited a decreased in the crystallinity. The scattered structure revealed through morphology analysis proved that cellulose treated with TEMPO had resulted in a more dispersed and separated cellulose fibre structure. Conclusion: The result showed, cellulose has been successfully modified using TEMPO-mediated oxidation with improved dispersion properties. The scattered structure revealed through morphology analysis proved that cellulose treated with TEMPO had resulted in a more dispersed and separated cellulose fibre structure. High cellulose dispersion ability will allow the manufacturing process of hydrogel, film and fibre to be much easier and faster. This is necessary for creating novel, environmentally friendly materials for various applications across numerous industries and future research anticipated to increase.

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ABSTRACT Background: The macauba (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) is a palm tree native to tropical regions and occurs in much of the Brazilian territory. Current studies are focused on the extraction and exploitation of vegetable oil from this fruit. However, there are few studies on the residue, the endocarp, which represents approximately 25% of the total mass of the fruit. Studies that search for solutions for using residue, thus adding value, and generating environmentally friendly products, are of fundamental importance. Thus, this research aimed to evaluate the physical and mechanical properties of reconstituted wood panels produced with different proportions of macauba endocarp particles to replace pine wood particles, in addition to characterize the physical and chemical properties of macauba endocarp. The chemical characterization tests were performed according to applicable standards. The basic density was determined according to the NBR 11941 standard. Thermogravimetric analysis (TGA), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR) were also performed. The particleboards panels were produced with a nominal density of 0.70g/cm³ and dimensions of 25x25x1.5cm. Five different treatments were evaluated with variations in the proportion of macauba endocarp particles in the core of the panel. For particle agglutination, phenol-formaldehyde adhesive was used at a proportion of 9% for the core and 12% for the faces, based on the dry mass of each panel. Scanning electron microscopy (SEM) was used to analyze the panel surfaces. Results: The endocarp of Acrocomia aculeata has low extractive content, high lignin content and high densification, 1.23g/cm³, when compared to Pinus oocarpa wood, 0.43g/cm³. All panels were classified as low density according to CS 236-66 and had an average apparent density between treatments of 0.586g/cm³. A greater dimensional stability and a decrease in the static bending properties of the panels was observed as the proportion of macauba endocarp particles increased. The internal bonding of the panels showed a positive result with the increase in the use of particles of the residue. Conclusion: The panels produced have potential for use for non-structural purposes.

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ABSTRACT Background: Paulownia tomentosa wood has chemical properties that satisfy the requirements for good raw material to obtain cellulose-based products, such as nanocellulose. Cellulose nanocrystals (CNC) are derived from naturally occurring cellulosic fibers, constituted of cellulose chains with an organizational setting that results in rigid rod-shaped crystals. This study assessed the wood wastes from Paulownia tomentosa Steud. as raw material for producing cellulose nanocrystals (CNC) using alkaline and delignification treatments, followed by a hydrolysis process with sulfuric acid at the 52% and 58% concentrations. The isolation of CNC from Paulownia tomentosa wood wastes was confirmed through different spectroscopic analyses. Results: The suspensions of nanocrystalline cellulose CNC-52 and CNC-58 showed yields of 8.34% and 7.62%, respectively. The particle size distribution of the suspensions, determined by the AFM technique, presented an average of L = 180.01 nm and W = 20.46 nm in CNC-52 and L = 128.06 nm and W = 10.18 nm in CNC-58. Moreover, the FTIR and XRD results demonstrated that there was no difference in the structure of the crystalline network and the chemical composition between cellulose (Kiri-CB) and the CNC. Conclusion: The results obtained from this study allowed to conclude that it is possible to employ the Paulownia tomentosa wood waste as a source of cellulose for extracting CNC by hydrolysis, adjusting the sulfuric acid concentration to 58% and maintaining it at 45 °C for 60 min.

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ABSTRACT Background: The use of X-rays non-destructive technique in color scale in 2D and 3D needs further studies to understand variations in the apparent density of wood stored under natural conditions. The objective of this study was to evaluate, by digital X-ray images and to test the rainbow scale in digital X-ray images in 2D and 3D, the apparent density of eucalyptus wood after storage in the field during 365 days. Trees of two diametric classes were randomly distributed at three heights in a pile in direct contact with the soil. The apparent density of the wood and its diametric profiles in the radial direction were determined using digital X-ray images in gray scale, and converted to a rainbow scale and the density variations plotted on a 3D surface. Results: The wood density decreased as the storage period increased. The density of the samples at 0 days of storage evaluated with the 3D images was homogeneous, while an intense attack by xylophagous organisms due to the exposure to the environmental conditions was observed in those collected at 365 days of storage. Conclusion: The rainbow scale color from X-ray images facilitated to visualize and to interpret the variation of apparent density distribution of the wood.

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ABSTRACT Background: Converting açaí waste fibers into kraft pulp and paper demands high amounts of preserved fibers. Manual removal preserves the fibers, but mechanical methods are faster. Therefore, this work aimed to compare three methods to extract açaí fibers from the seed’s surface concerning efficiency and fiber quality for cellulose pulping. Results: Açaí waste fibers have ≈ 34 % of cellulose and ≈ 61% of non-cellulose structural components (based on extractive free mass) and ≈ 6% of non-structural extractives and ashes (based on total mass). They occur united into bundles that dissociate into short (388 µm) fiber cells. Their pulp-paper quality indexes were aspect ratio (31.8-41.2), wall fraction (52.8 %), flexibility coefficient (47.2 %), boiler index (0.6), Runkel index (1.2), and Mulsteph index (0.8). The manual removal preserved the fibers but had the lowest efficiency (0.1 g/min). The food processor provided intermediate preservation of the fibers and efficiency (0.5 g/min). Despite the highest efficiency (3.9 g/min) of the hammer mill method, the friction with the hammers damaged the fibers and increased the levels of extractives from 4 to 8% and hemicelluloses from 34 to 40%. Conclusion: Açaí waste fiber bundles are dissociable into short fibers and have a favorable chemistry for kraft pulping and developing cellulose products. The fiber morphology is not ideal, but not limiting, demanding adjustments in the future kraft pulping parameters. The extraction of the fiber by the food processor is recommended, which is manageable to the local communities to support an integrated bioeconomy of the açaí waste.

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ABSTRACT Background: The production of cellulose microfibrils/nanofibrils (CMF/CNF) has attracted increasing attention in recent decades due to their excellent barrier, mechanical, and surface chemistry properties. However, large-scale industrial production of CMF/CNF has been a major challenge due to their high energy consumption, limiting their application. In this context, in recent years many studies have focused on developing pre-treatments designed to facilitate the fibrillation of CMF/CNF by reducing energy consumption during their production. This review highlights the latest advances in the use of silicates as chemical pre-treatments for CMF/CNF production, covering the main aspects related to the effects of chemical modification on the production and the properties of materials for application in biodegradable packaging. Results: Energy consumption reductions of up to 30% were achieved by pretreating cellulose pulps using silicates. In addition, the pre-treatments resulted in smaller CMF/CNF diameters and greater individualization of the nanofibrils. Studies evaluating the thermal stability, hydrophobicity, mechanical properties, and porosity of CMF/CNF pre-treated with silicates have reported promising results. The application of CMF/CNF pretreated with calcium and magnesium silicates in cardboard coating resulted in packaging with low water vapor permeability and high ductility. Conclusion: Silicates interact well with cellulose surfaces, making them a promising material for the chemical pre-treatment of CMF/CNF. Furthermore, the modification by silicates could be an interesting strategy for expanding the use of CMF/CNF in the development of new products.

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ABSTRACT Background: Acacia mearnsii and Eucalyptus dunnii are species planted mainly for tannin and cellulose production. However, its woods have characteristics favorable to their use for energy generation, being commercialized in the form of firewood, chips or charcoal too. Biochar is a stable form of carbon that can be obtained by converting small particles of wood in the pyrolysis process and that can be used as solid fuel, among other applications as a soil conditioner. In this study, the properties of biochar produced in a horizontal reactor using wood of these species and under milder temperatures were evaluated. Results: Temperature of 350 oC and the reaction time of 30 minutes promoted an increase in higher calorific value of 33% for A. mearnsii and 51% for E. dunnii, with gravimetric yield of 39% and 32%, respectively. it was found that the 250 and 300 oC was not efficient to carbonize the wood of both species. An increase in specific surface area is observed with increasing carbonization temperature. Bigger increases were produced at temperatures of 350 oC for E. dunnii and 420 oC for A. mearnsii, with increase in porosity. At these temperatures, there was an increase in surface area and a decrease in pore size. Conclusion: In temperatures of 350 oC, the woods of both species provided a good quality biochar with porosity, surface area, pore size and pyrolysis yield suitable for energy use. For soil conditioning use, considering these aspects, suggested to test the appropriate temperatures for each species, between 350 and 420 oC.

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ABSTRACT Background: Natural weathering reduces the durability of wood products. In this situation, preservative surface treatments are recommended for wood products to increase life and resistance and decrease the wood’s hygroscopic capacity. This study aimed to evaluate the surface characteristics of three Amazonian wood species - Schizollobium parahyba var. amazonicum , Cordia goeldiana, and Manilkara elata - treated with a silicon-based nanoproduct. Results: The species were classified according to the following classes of basic density: low (<0.550 g cm-3), medium (between 0.550 and 0.720 g cm-3), and high density (> 0.730 g cm-3). The nanoproduct was sprayed along the grain of the wood samples. Wettability, roughness, and colorimetric properties were determined before and after treatment application. The application of the nanoproduct significantly reduced the wettability of the wood, particularly in S. parahyba var. amazonicum, which showed a 117% increase in contact angle, indicating lower hydrophilicity. Although the application of the nanoproduct affected the colorimetric parameters (L*, a*, and b*), the colorimetric grouping table showed that the colors of the wood did not change. Additionally, the surface roughness of S. parahyba var. amazonicum increased significantly post-treatment compared to untreated samples. Conclusion: Therefore, the nanoproduct can be indicated for low, medium, and high-density wood species and for purposes that need to maintain their natural color and reduce their hydrophilicity.

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ABSTRACT Background: Anadenanthera colubrina (Vell.) Brenan, commonly known as angico, is a species of high socioeconomic and environmental value, distinguished by its high concentration of tannins in various plant parts. This study aimed to co-validate the quantification method of tannins and associate their quantification with data on the development of young specimens of Anadenanthera colubrina (Vell.) Brenan from different environments. Seeds were collected in two areas in the Western Cariri of Paraíba. Plants were evaluated regarding their height, diameter, fresh and dry mass, and tannin quantification 90 days after emergence. Partial validation was performed in accordance with current Brazilian legislation. Results: Regarding the development data, only height was statistically different between the study areas, and the specimens from Sumé were the highest (73.6 cm) ones. The tannin quantification method proved to be selective, linear, accurate, and robust, with analytical reliability in the quality control of the plant drug the of part aerea. Principal component analysis justified 79.3% of the data, evidencing the efficiency of the adopted model. Two main groups were formed, in which biomass and diameter data were associated with specimens of matrices from Serra Branca, whereas specimens from Sumé were more related to tannin production and plant height. Conclusion: This set of data contributes to the sustainable use of the species and is promising in the innovation and technological development of sustainable products based on raw materials rich in tannins from A. colubrina.