Abstract Introduction: The great diversity of tropical timber species demands the development of new technologies capable of identifying them based on their patterns or anatomical characteristics. The application of convolutional neural networks (CNN) for the recognition of tropical timber species has increased in recent years due to the promising results of CNNs. Objective: To evaluate the quality of macroscopic images with three cutting tools to improve the visualization and distinction of anatomical features in the CNN model training. Methods: Samples were collected from 2020 to 2021 in areas of logging and sawmills in the Central Jungle, Peru. They were later sized and, after botanical and anatomical identification, cut in cross sections. A database of macroscopic images of the cross-section of wood was generated through cutting with three different tools and observing its performance in the laboratory, field, and checkpoint. Results: Using three cutting tools, we obtained high quality images of the cross section of wood; 3 750 macroscopic images were obtained with a portable microscope and correspond to 25 timber species. We found the ''Tramontina'' knife to be durable, however, it loses its edge easily and requires a sharpening tool, the ''Pretul'' retractable cutter is suitable for cutting soft and hard wood in small laboratory samples and finally the ''Ubermann'' knife is suitable for use in the field, laboratory, and checkpoint, because it has a durable sheath and interchangeable blades in case of dullness. Conclusion: The quality of the images is decisive in the classification of timber species, because it allows a better visualization and distinction of the anatomical characteristics in training with the EfficientNet B0 and Custom Vision convolutional neural network models, which was evidenced in the precision metrics.

Resumen Introducción: La gran diversidad de especies maderables tropicales demanda el desarrollo de nuevas tecnologías de identificación con base en sus patrones o características anatómicas. La aplicación de redes neuronales convolucionales (CNN) para el reconocimiento de especies maderables tropicales se ha incrementado en los últimos años por sus resultados prometedores. Objetivo: Evaluamos la calidad de las imágenes macroscópicas con tres herramientas de corte para mejorar la visualización y distinción de las características anatómicas en el entrenamiento del modelo CNN. Métodos: Recolectamos las muestras entre el 2020 y 2021 en áreas de explotación forestal y aserraderos de Selva Central, Perú. Luego, las dimensionamos y, previo a la identificación botánica y anatómica, las cortamos en secciones transversales. Generamos una base de datos de imágenes macroscópicas de la sección transversal de la madera, a través del corte, con tres herramientas para ver su rendimiento en el laboratorio, campo y puesto de control. Resultados: Usamos tres herramientas de corte para obtener una alta calidad de imágenes transversales de la madera; obtuvimos 3 750 imágenes macroscópicas con un microscopio portátil que corresponden a 25 especies maderables. El cuchillo ''Tramontina'' es duradero, pero pierde el filo con facilidad y se necesita una herramienta para afilar, el cúter retráctil ''Pretul'' es adecuado para madera suave y dura en muestras pequeñas de laboratorio; el cuchillo ''Ubermann'' es apropiado para el campo, laboratorio y puesto de control, porque tiene una envoltura duradera y láminas intercambiables en caso de pérdida de filo. Conclusiones: La calidad de las imágenes es decisiva en la clasificación de especies maderables, porque permite una mejor visualización y distinción de las características anatómicas en el entrenamiento con los modelos de red neuronal convolucional EfficientNet B0 y Custom Vision, lo cual se evidenció en las métricas de precisión.

ABSTRACT Background: The biodiversity of the Peruvian Amazon tropical forests is one of the most expressive in the world, with 2500 forest species, although restricted to about 250 tree species used commercially. This species diversity indicates the challenge magnitude for research in taxonomy and timber species identification. Likewise, it implies the complexity of biodiversity conservation and restoration measures, which are directly related to the control of deforestation, cutting and transport of illegal wood. With this objective, the present study describes the macroscopic wood anatomical features in order to identify 20 tree species from Peruvian Amazon Forest, “Selva Central”, including an identification key and tree species botanical validation. Results: The wood species are included in 12 families commonly found in the tropical forests of Peru, highlighting the Fabaceae (25%), Moraceae (15%), Podocarpaceae and Lauraceae (10%) families and are sold as timber for several uses and applications in the internal market and for export. The wood species presented common anatomical features, such as diffuse porosity, visible axial parenchyma mainly distinct, and, eventually, with ray storied, e. g: A. cearensis, M. balsamum and M. peruiferum. Conclusion: The tropical tree species identification is possible by analyzing their wood macroscopic anatomical structure. The results can be also applied in the wood trade traceability by controlling deforestation and illegal wood commerce and in proposing policies for biodiversity conservation and sustainable use of natural resources. They constitute, likewise, a database for the recent wood identification methodologies presented in the specialized literature.

ABSTRACT Background: Knowledge of the anatomy and properties of wood help to understand the quality of wood and plan its ideal technological use, therefore, it is necessary to understand the variations in wood characteristics and properties. Here we evaluate the radial variation of wood density and fiber morphology of two commercial forest species in a tropical humid forest of the department of Madre de Dios in Peru: Jacaranda copaia and Hura crepitans collected in a management area. Results: Forestry collecting 10 usable trees by species. We provide general values of the densities and fibers of the two species studied. Conclusions: Regarding the variation of the radial density, J. copaia presented a density growth in the pith-bark direction, while for H. crepitans its variation was not significant, these variations are clearly explained by the morphology of its fibers.

Resumen: En el presente trabajo se determinaron los parámetros colorimétricos mediante el sistema CIELAB y la densidad aparente por densitometría de rayos X en madera de Guazuma crinita para obtener información de su calidad en el uso como madera solida o transformada. La evaluación se realizó en tres niveles del eje axial (basal, medio y apical) de una plantación de 5 y 8 años, en la zona de Puerto Inca, departamento de Huánuco, Perú. En ambas edades, empleando el sistema CIElab, se encontró que la madera es de coloración homogénea y se clasifica como rosa grisáceo. La densidad aparente medida por densitometría de rayos X en el sentido médula - corteza fue de 520 kg/m3 y 560 kg/m3 para 5 y 8 años respectivamente; con promedios mayores en el nivel basal (5 años: 650 kg/m3; 8 años:680 kg/m3) y menores en el nivel apical (5 años: 430 kg/m3; 8 años: 470 kg/m3). Los perfiles densitométricos mostraron, en general, que radialmente hay un aumento de la densidad aparente en el sentido médula - corteza. La densidad de la madera madera de 5 años resultó más uniforme que la de 8 años con un índice de uniformidad de 149,7 y 170,3, respectivamente.

Abstract: In the present work, the colorimetric parameters were determined using the CIELAB system and the apparent density by X-ray densitometry in Guazuma crinita Mart. wood to obtain information of its quality in use as solid or transformed wood. The evaluation was carried out in three levels of the axial axis (base, medium, apical) of one plantation of 5 and 8 years old, in Puerto Inca, department of Huánuco, Peru. It was found that in both ages, according to CIElab system, the wood is of homogeneous coloration and is classified as greyish pink. The apparent density measured by X ray densitometry in the pith - bark direction was found to be 520 kg/m3 and 560 kg/m3 for 5 and 8 years, respectively; with higher values at the basal level (5 years old: 650 kg/m3; 8 years old: 680 kg/m3) and lower towards the apical part (5 years old: 430 kg/m3; 8 years old: 470 kg/m3). The densitometric profiles showed, in general, that there is an increase in apparent density radially in the pith-bark direction. The 5-year-old wood density was more uniform than the 8-year-old one with a uniformity index of 149,7 and 170,3, respectively.

Abstract: This study set out to determine which environmental factors of growth and silvicultural practices can affect the properties of Eucalyptus robusta coppice wood and also to study variability in those properties depending on the factors. Hundred and thirty-five coppice logs aged 2 to 10 years were collected from five zones in the Highlands of Madagascar. Wood density at 12% moisture content was measured by X-ray microdensitometry. Chemical properties, such as the total extractives, Klason lignin and holocellulose contents were predicted using near infrared spectrometry prediction models. The results significantly showed (p-value<0,001) that wood density (543 - 836 kg/m3), total extractives (3,1 - 9,8%) and Klason lignin content (24,6 - 35,3%) increased with age, with the opposite occurring for holocellulose (63,8 - 69,9%). Wood density also varied significantly (p-value<0,001) depending on the zones, which was not the case for chemical properties. The densest woods were found at the hottest zones with less acid soils. Woods were less dense in zones, characterized by high rainfall and a soil rich in nitrogen and organic carbon. The plantation spacing, elevation of the zone and soil texture did not significantly affect wood properties.

Abstract: The aim of the present study was to determine the physical properties of the Guazuma crinita wood by conventional methods, as well as to estimate these properties by near infrared spectroscopy (NIR) through the development of multivariate calibration models. The samples were obtained from five trees and from three levels longitudinally for 5 and 8 years of age randomly selected from a plantation in Puerto Inca, Department of Huánuco (Perú). Basic density, volumetric, tangential and radial contraction were determined by the conventional methods. Models were developed by regression of partial least squares (PLS) through mathematical transformations. For the validation of the models, a new group of samples -which did not participate in the development of the model were used. Statistical significance was found F 5años = 191,5; F 8 años =84,9) between the different heights in the stem. Basic density and volumetric contraction show values of (0,88 and 0,83) and RPDp (1,55 and 3,27) acceptable for prediction.

Resumen: El objetivo del presente estudio fue determinar las propiedades físicas de la madera de Guazuma crinita por el método convencional, así como estimar estas propiedades por espectroscopia infrarroja cercana (NIR) a través del desarrollo de modelos de calibración multivariada. Las muestras fueron obtenidas de tres niveles del eje longitudinal en 5 árboles para 5 y 8 años de edad seleccionados al azar de una plantación en la zona de Puerto Inca, departamento de Huánuco (Perú). Se determinó la densidad básica, contracción total volumétrica, tangencial y radial por el método destructivo o convencional. Los modelos fueron desarrollados por regresión de mínimos cuadrados parciales (PLS) mediante transformaciones matemáticas. Para la validación de los modelos se empleó un grupo de muestras que no participo en el desarrollo del modelo. Se encontró diferencias estadísticas significativas (F 5años = 191,5; F 8años =84,9) entre las tres alturas en el fuste. Para densidad básica y contracción volumétrica se encontró valores de (0,88 y 0,83) y RPDp (1,55 y 3,27) aceptables para la predicción.

ABSTRACT The Atlantic Forest of southeastern Brazil has been considered to have the highest number of tree species per hectare in the world. Assessing the influence of climate on tropical tree species is a priority in the face of ongoing climate change, and for which dendrochronological studies have been important. We address the dendrochronological potential of Licaria bahiana Kurz (Lauraceae), an endemic species of the Atlantic forests. We studied growth ring anatomy of L. bahiana and applied dendrochronological methods to investigate how short-term variation in climate affect its radial growth. Distinct growth rings were observed in all individuals and demarcated by darker tangential fiber zones in latewood. Trees showed high climatic sensitivity (0.48) and growth synchrony (intercorrelation r = 0.69; rbar = 0.38). Radial growth was negatively influenced by high temperatures at the beginning of the current growing season (r = -0.46) and by excessive rainfall at the end of the current growing season (r = -0.29), which are periods that correspond to the phenological reproductive phases of the species. Climate anomalies during this period may alter the tradeoff between growth and reproduction, in favor of the latter.

ABSTRACT The aim of this study was to evaluate the effects of potassium and sodium fertilization (control: 4.5kmol.ha-1 of KCl and 4.5kmol.ha-1 of NaCl), and water regimes (100% and 63% rainfall with artificial exclusion) on wood and briquette density in Eucalyptus grandis trees at 5 years, and the application of X-ray densitometry on the quality of briquettes. Tree trunk samples were obtained to determine wood density, production and briquette density by X-ray densitometry and stereometric. The artificial exclusion of rainwater promoted an increase in wood density, and the fertilization treatments versus water availability did not affect the density of briquettes. The method used to determine the briquette density influenced the average values, with an increase of 12% in the X-ray densitometry to the stereometric.

ABSTRACT The productive sustainability of eucalyptus planting is threatened when both diseases and disorders of growth occur. These interferences can have abiotic origin as environmental conditions can negatively affect the wood quality. This study has the goal of evaluating influence of different levels of physiological disorders in dendrometric variables and wood quality from seven-year-old Eucalyptus grandis x Eucalyptus urophylla hybrids intended for wood pulping production. The trees from commercial plantations in State of Maranhão, Brazil were separated into three levels of physiological disorders by means of morphologic changes. Then, they were evaluated according to dendrometric variables, anatomical characteristics, chemical properties, density of wood, and kraft pulp process. The physiological disorder levels significantly influenced all evaluated properties. Moreover, the wood from trees with higher severity of symptoms resulted in higher average values of dendrometric variables, basic density, and fibers dimensions. In addition, apparent density exhibited a different standard in the pith region with increase on radial wood profile. Trees with the least severe disorders exhibited changes in dendrometric and anatomical variables, mainly in wood volume and fibers dimensions, respectively.

ABSTRACT The use of wood in the form of charcoal for energy production, has great economic importance in Brazil. In this context, the study of variables and mechanisms that affect charcoal quality is essential. The present study aimed to verify the influence of some physical properties of Eucalyptus wood on the quality and yield of the produced bioreducer. We used three commercial Eucalyptus clones, cultivated for use in the steel industry, determining wood density and shrinkage, density and immediate chemistry of the charcoal produced and the charcoal gravimetric yield. The data was submitted to Pearson’s correlation analysis. Correlations between wood density and apparent charcoal density as well as charcoal ash content were observed. All clones presented characteristics suitable for the production of charcoal for the steel industry, with emphasis on the hybrid E. urophylla x E. grandis.

RESUMO A madeira de eucalipto de árvores adultas é utilizada para os mais diversos fins, entretanto, a utilização desta madeira de árvores de idade precoce é limitada. O objetivo foi caracterizar e propor utilizações para madeira de eucalipto com dois anos de idade. Seis clones de Eucalyptus grandis × Eucalyptus urophylla, com dois anos de idade, foram selecionados e suas características anatômicas, ultraestruturais, físicas e mecânicas avaliadas. A madeira do clone A apresentou fibras mais robustas e de melhor arranjo microfibrilar, resultando em melhores propriedades mecânicas e, por isto, melhor desempenho para uso estrutural. O clone F apresentou madeira com pouca variação da densidade básica no sentido radial, facilitando sua trabalhabilidade e, com o clone B, apresentou menor coeficiente de anisotropia e, por isto, a madeira é recomendada para locais com alta variação de umidade. A heterogeneidade das características da madeira dos clones avaliados corrobora a necessidade estudos por clone para uma sua melhor utilização.

ABSTRACT Eucalyptus wood from adult trees is used for several purposes; however, the wood of younger trees has limited use. This study aims to characterize and propose uses of two-year-old eucalyptus wood. Six two-year-old Eucalyptus grandis × Eucalyptus urophylla clones have been selected and their anatomical, ultrastructural, physical and mechanical wood characteristics evaluated. The wood of Clone A shows more robust fibers with better microfibril arrangement, resulting in better mechanical properties, and therefore, a better performance for structural use. Clone F showed a low variation of wood basic density in the radial direction, facilitating its machinability, and with the Clone B, showed a lower anisotropy, and therefore, the wood is recommended for locations with high variations of humidity. The heterogeneity of the wood characteristics of the evaluated clones confirms the need for further studies, to choose those most adequate to each use.

RESUMO Expressiva área das plantações florestais de eucalipto de rápido crescimento no Brasil e em outras regiões do mundo encontra-se sob o efeito das mudanças climáticas, do estresse hídrico e da baixa fertilidade do solo, afetando o crescimento e a qualidade do lenho das árvores. O presente trabalho teve como objetivo avaliar a densidade aparente a 12% de umidade do lenho das árvores de Eucalyptus grandis com 12, 24 e 36 meses, com redução da precipitação pluviométrica e nutrição de K e Na. Os tratamentos foram definidos por dois regimes hídricos (100 e 66% das chuvas, com redução artificial com lonas de polietileno) e três tipos de nutrição: K (K - 4,5 kmol/ha), N (Na - 4,5 kmol/ha) e controle. A densidade aparente a 12% de U.R. das amostras da posição do DAP do tronco das árvores foi determinada pela densitometria de raios X e por imagens digitais do lenho. Os resultados indicaram diferença significativa da densidade aparente a 12% de U.R. das árvores de eucalipto nos tratamentos de nutrição e de disponibilidade hídrica. O perfil radial de densidade aparente mostrou maior diferença a partir do terceiro ano de idade das árvores. Pelas imagens digitais, analisou-se a variação radial da densidade aparente da madeira. Os resultados do trabalho fornecem subsídios para a adoção de práticas silviculturais nas áreas de plantações florestais com estresse hídrico e/ou afetadas pelas mudanças climáticas, bem como a substituição parcial de K por Na.

ABSTRACT Expressive area of forest plantations fast-growing of eucalyptus in Brazil and in other regions of the world is under the influence of climate change, water stress and low soil fertility, affecting the growth and the quality of the wood from the trees. This study aimed to evaluate the apparent density at 12% relative humidity of the wood of Eucalyptus grandis trees with 12, 24 and 36 months, with reduced rainfall and nutrition K and Na. The treatments were defined by two water regimes (100% and 66% of rainfall, with artificial reduction with polyethylene sheeting) and three types of nutrition: K (K - 4.5 kmol/ha), N (Na - 4.5 kmol/ha) and control. The apparent density of the samples of diameter at breast height was determined by densitometry profile from digital images of rays X. The results indicated a significant difference in nutrition treatments and water availability in relation to the density of the wood. The radial apparent density profiles showed higher differences in the wood from the third year of evaluation. Digital images of the wood obtained by X-rays allowed to analyze the variation of the apparent density of the wood. Work results may be used as subsidies for the adoption of silvicultural practices in forest plantations in areas with water stress and/or affected by climate change as well as the partial replacement of K by Na.

RESUMO O estudo teve como objetivo analisar as propriedades físicas e mecânicas do carvão de clones de eucalipto por análise de componentes principais e demonstrar as correlações entre essas propriedades, a fim de avaliar qual propriedade de carvão deve ser almejada no processo para obter um produto de alta qualidade. Desta forma, foram cortados oito clones de Eucalyptus e dois de Corymbia, coletando três árvores por clone e cinco discos em diferentes alturas. Os discos foram transformados em amostras para ensaio, totalizando uma média de 75 amostras por clones, que foram carbonizados sob condições específicas para a análise da densidade aparente, compressão paralela às fibras e degradação linear e volumétrica devido à alta temperatura. Vale ressaltar que os dados foram ponderados pelo disco e por árvore, para a uma média mais próxima da realidade. Para as correlações, foi utilizada a análise multivariada de componentes principais. Nisto, verificou-se a ação da densidade aparente do carvão como o ponto focal das outras propriedades estudadas e observou-se que quanto maior a densidade, maior será a força de compressão paralela à grã, o módulo de elasticidade e o rendimento gravimétrico.

ABSTRACT The study aimed to analyze the physical and mechanical properties of charcoal from eucalypt clones by principal component analysis and demonstrate the relationships between these properties, in order to assess which charcoal property should aimed in the process to obtain a higher quality product. In this way, was cut eight clones of Eucalyptus and two of Corymbia, collecting three trees per clone and five disk in different heights. The disks were transformed into test samples, totaling an average of 75 samples per clones, which were carbonized under specific conditions for analysis of apparent density, compressive strength parallel to grain and linear and volumetric degradation due to high temperature. It is noteworthy that the data were weighted by disk and per tree, to an average closer to reality. For correlations, was used multivariate analysis of principal components. Herein, it is found that the apparent density of charcoal acts as the focal point of the other properties studied, and observed that as the higher the density, higher will be the compressive strength parallel to grain, the elastic modulus and the gravimetric yield.

RESUMO As árvores de Pinus taeda – introduzidas no Brasil em 1880 e em ensaios experimentais em 1936 – têm sido relacionadas na literatura especializada ao processo de invasão biológica de algumas áreas de campos gerais e de altitude dos estados do Paraná e Santa Catarina, de cerrado no estado de São Paulo, de restinga no estado de Santa Catarina e de pampas no estado do Rio Grande do Sul. Os anéis de crescimento anuais formados no lenho das árvores de Pinus taeda constituem importante ferramenta na avaliação do processo de invasão biológica. Com esse objetivo, no presente trabalho avaliou-se a dispersão espacial-temporal de sementes analisando-se os anéis de crescimento do lenho de árvores de Pinus taeda de plantações e de regeneração natural na região de Faxinal do Céu, estado do Paraná. Os resultados possibilitaram determinar a idade e a taxa de crescimento do tronco das árvores de Pinus taeda de plantações, a data da germinação, a área de dispersão das sementes e a taxa de crescimento das árvores de regeneração natural. Os resultados permitem, da mesma forma, discutir o processo de invasão de árvores de Pinus taeda pela dispersão das sementes em áreas limítrofes às plantações florestais.

ABSTRACT The Pinus taeda trees - introduced in Brazil in 1880 and in experimental trials in 1936 - have been listed in specialized literature of biological invasion process in some areas of general fields and altitude of the states of Parana and Santa Catarina such as, the savanna in the state São Paulo, sandbar in the state of Santa Catarina and pampas in the state of Rio Grande do Sul. The annual tree-rings formed in the wood of Pinus taeda trees constitute an important tool in the evaluation of the biological invasion process. The present study aimed to evaluate the spatial-temporal dispersion of seeds by analyzing the tree-rings of Pinus taeda trees from plantations and natural regeneration in the region of Faxinal do Céu, state of Paraná. The results allowed determining the age and growth rate of the pine trees trunk from plantations; the date of germination, the seed dispersal area and the growth rate of trees of natural regeneration. The results allow, likewise discussing the invasion process of pine trees by seed dispersal in areas close to forest plantations.

Resumen En los procesos de transformación y aserrío de la madera se generan residuos que pueden usarse como fuentes de materia prima para la producción de pellets. El objetivo de este trabajo fue evaluar la eficiencia, la calidad por imágenes de rayos X y las propiedades energéticas, físicas y mecánicas de pellets fabricados con residuos obtenidos del procesamiento de trozas de Cupressus lusitanica y Tectona grandis. Los resultados indicaron un porcentaje de eficiencia bajo para ambas especies forestales, con 25% para C. lusitanica y 20% para T. grandis. En la evaluación de calidad, los pellets de C. lusitanica se caracterizaron por poseer zonas de mayor claridad y pocas fisuras de corto tamaño en su superficie, mientras que en los de T. grandis se presenta un mayor número de zonas de mayor claridad, además de mostrar fisuras de mayor profundidad y largo. En relación con las propiedades evaluadas, se encontró que los pellets de T. grandis tienen una menor densidad aparente, menor PC, menor resistencia a la compresión y menor uniformidad en la densidad de su superficie y un porcentaje de cenizas, CH y durabilidad mecánica mayor, al compararlos con los de C. lusitanica.

Abstract The process of transformation and sawmilling of sawlog generates residuals that can be used as sources of raw material for the production of pellets. The aim of this study was to evaluate the efficiency, pellet quality for x-ray photographic and the energetic, physical and mechanical properties of pellets fabricated from residuals obtained from processing sawlogs of Cupressus lusitanica and Tectona grandis. The results showed a percentage of low efficiency for both species, 25% for C. lusitanica and 20% for T. grandis. In the quality evaluation, pellets were found that pellet fabricated with C. lusitanica pellets is characterized by having high density areas (about 1300 kg m-3) and few cracks of short size on the surface. But the pellets of T. grandis residues present an irregular density (high and low density in the pellet) and present deeper and longer cracks. Regarding the properties evaluated, it was found that the pellets of T. grandis were characterized by having a lower apparent density, lower net calorific power, lower resistance to compression and lower uniformity in the density of its surface and a greater percentage of ash, moisture content and mechanical durability, if they are compared with pellets of C. lusitanica.