Abstract: This evaluated the natural resistance of wood from seven Eucalyptus trees in field decay and soil bed tests. Two 12-year-old trees were randomly sampled per species, with 2,2 m logs being obtained from the basal section of each tree. The samples were taken in two positions in the radial direction of the stem (middle heartwood and transition zone; containing heartwood and sapwood). The field decay tests were installed in three municipalities in the southern state of Espírito Santo, and the soil utilized soil from the three field decay test areas. The field decay tests were evaluated after six, 12 and 18 months after installation and the soil bed tests after six months. The Scott-Knott test (p ≤ 0,05) was used in the analysis and evaluation of the tests. The sapwood-heartwood (transition region) exhibited the greatest mass losses for the field decay and soil bed tests. On average, for the soil bed test the lowest mass losses were observed for the soil of Vargem Alta (5,00 %), with greater mass losses observed for São José do Calçado (7,05 %) and Jerônimo Monteiro (9,90 %). In the field decay test the organisms present in the soil of São José do Calçado and related to the organic matter content Eucalyptus grandis and Eucalyptus saligna more intensely.

RESUMO O objetivo deste trabalho foi avaliar a influência de diferentes áreas úteis proporcionadas pelos espaçamentos de plantio (3 × 1, 3 × 2, 3 × 3, 3 × 4 m) na produção e na permeabilidade do cerne e do alburno da madeira de clones de Eucalyptus grandis e Eucalyptus grandis × Eucalyptus urophylla, aos 4 anos de idade. Independente do clone, não houve efeito do espaçamento de plantio na relação cerne/alburno e na permeabilidade da madeira. Todos os clones apresentaram um decréscimo na quantidade de cerne com o aumento da altura do fuste, independentemente do espaçamento de plantio, e o E. grandis (B) foi o único que a percentagem de cerne correlacionou-se positiva e significativamente com as variáveis dendrométricas (DAP e altura comercial). O uso do composto dymethil yellow foi indispensável na demarcação das regiões do cerne e do alburno nas amostras a partir de 50% da altura do fuste. A permeabilidade do cerne foi baixa em todos os clones avaliados, sugerindo obstrução dos vasos por tilas ou outras substâncias, enquanto a permeabilidade do alburno atingiu 405,4 cm3/cm.atm.s.

ABSTRACT The objective of this work was to evaluate the influence of different useful areas provided by the planting spacings (3 × 1, 3 × 2, 3 × 3, 3 × 4 m) on the production and permeability of heartwood and sapwood of Eucalyptus grandis and Eucalyptus grandis × Eucalyptus urophylla clones at 4 years old. Regardless of the clone, there was no effect of planting spacing on the heartwood/sapwood relation and wood permeability. All clones showed a heartwood decrease with increased height, regardless of planting spacing, and E. grandis (B) was the only one that had its heartwood percentage positively and significantly correlated with the dendrometric variables (DBH and commercial height). The use of the dymethil yellow compound was indispensable in defining the heartwood and sapwood regions in the samples from 50% of the stem height. The heartwood permeability was low in all evaluated clones, suggesting vessel obstruction by tyloses or other deposits, while sapwood permeability reached 405.4 cm3/cm.atm.s.

RESUMO Esta pesquisa objetivou avaliar o ambiente de trabalho em uma fábrica de produção de ferramentas. Este processo envolve as atividades de corte, orvado, viragem, forjadora, têmpera, inserção de cabos, esmeril, envernizamento e soldagem. Para avaliar o conforto térmico foi utilizado o IBUTG, para medir a velocidade do vento o anemômetro, luxímetro para avaliar a luminosidade e decibelímetro para analisar a exposição dos trabalhadores ao ruído. Os dados de IBUTG variaram em média de 20,9°C a 27,3°C. A forjadora apresentou os maiores valores de IBUTG em média durante todo o processo produtivo. Todas as atividades apresentaram velocidade do vento abaixo de 0,75 m/s, sendo aceitável para a jornada de trabalho. A iluminância, em média oscilou de 42,9 lux a 393,3 lux. As atividades de envernizamento, têmpera, forjadora e inserção de cabos apresentaram médias de iluminância abaixo dos 150 lux necessários durante toda a jornada de trabalho. Todas as atividades apresentaram ruídos acima de 85 dB(A), exceto o envernizamento e o corte. Os níveis de ruído variaram em média de 79,7 dB(A) no envernizamento às 8 h a 95,7 dB(A) no esmeril às 13 h.

ABSTRACT This research aimed to evaluate the work environment in a tool manufacturing factory. This process involves the cutting activities, orvado, turning, forger, temper, cable insertion, grinding, welding and varnishing. To evaluate the thermal comfort was used IBUTG to measure the wind speed anemometer, lux meter to evaluate the brightness and decibel meter to analyse the exposure of workers to noise. The data ranged IBUTG on average 20.9°C at 27.3°C. The forger had the highest IBUTG values averaged over the entire production process. All activities had wind speeds below 0.75 m/s, being perfectly acceptable for the entire workday. The average luminance oscillated from 42.9 lux to 393.3 lux. The activities of varnish, temper, forger and cable insertion had average illuminance below 150 lux required throughout the workday. All activities presented noise above 85 dB(A), except the varnishing and cutting. Noise levels ranged on average of 79.7 dB(A) in varnishing at 8 hours 95.7 dB (A), in the grinding at 13 hours.

Abstract: This study is a continuation of a previous study published in this journal, with the aim of evaluating the effect of the Brazilian industrial thermal modification process on some physical properties of Eucalyptus grandis juvenile wood. Flatsawn boards of juvenile wood were tested for four treatment levels: untreated and thermally modified wood at final cycle temperatures of 140 °C, 160 °C and 180 °C. Physical properties were assessed according to a standard of the Comisión Panamericana de Normas Técnicas and a method proposed by the specialized literature encompassing equilibrium moisture content (a measure of wood’s hygroscopicity), density (oven-dried and air-dried) and radial, tangential and volumetric swelling (from oven-dried to green moisture content). Thermally modified Eucalyptus grandis wood became less hygroscopic, more dimensionally stable (tangential and volumetric swelling) and less dense, even at the lowest temperature tested (140 °C), except for radial swelling, which did not differ from untreated wood.

ABSTRACT This study aimed to evaluate the environmental effect on the wood chemical composition of Eucalyptus grandis x Eucalyptus urophylla clones for pulp production. Seven clones of 6.5 years old were evaluated. The clones were planted in two growing sites, Nova Almeida - Espírito Santo and Posto da Mata - Bahia, established in 3 x 3 m spacing. Five trees were selected from each clone and discs were removed from five different positions equidistant from the trunk and at diameter at breast height (DBH) height. Two wedge from opposite sides were obtained from the discs. A chemical analysis was performed with a sample composed of all the wedges of each tree in order to determine extractive contents, lignin, holocellulose, carbohydrates and the ratio among syringyl (S) and guaiacyl (G) lignin substructures (S/G) per tree. The S/G ratio was considered to be the most stable characteristic to environmental change, followed by the holloceluloose content, which was considered the second least characteristic influenced by the growth site. Most of the studied clones presented a statistical difference between the growing site for the wood extractive content, in contrast to the total carbohydrates content that was highlighted by presenting values which were little influenced by the genetic material and the growth site.

Abstract: The aim of the research was to evaluate the effect of the attack Leptocybe invasa in dendrometric variables and wood properties of two clones of eucalyptus (Eucalyptus urophylla and Eucalyptus tereticornis), grown in the municipalities of Imperatriz (state of Maranhão) and Darcinopolis (state of Tocantins), Brazil, for Kraft pulping. Data were collected 10 trees for each clone, the 3-year-old attacked by L. invasa. The diagnosed was based on formation of large guts all over the glass, and emergency hole (closing the loop). The results were confirmed by the variation of the characteristics of species assessed relative to their total height, diameter, volume of bark, vessel frequency, fiber size, radial density profile vessel frequency, fiber size, radial density profile, and ash content. Host trees obtained alterations in dendrometric variables, content of pentosans and wood ashes for both genetic materials, not being observed variations in specific gravity, and size of vessels and fibers, as well as the contents of lignin and wood extractives.

Resumen: El objetivo de la investigación fue evaluar el efecto del ataque de Leptocybe invasa en las propiedades dendrométricas de la madera de dos clones de eucalipto (Eucalyptus urophylla y Eucalyptus tereticornis), cultivados en los municipios de Imperatriz (Estado do Maranhão) y Darcinópolis (Estado de Tocantins), Brasil, destinados a la producción de pulpa kraft. Se analizaron 10 árboles de 3 años de edad atacados por Leptocybe invasa, para cada clon. El diagnóstico fue basado en la formación de grandes agallas en la copa, y con orificio de emergencia (cerrando el ciclo). Los resultados fueron constatados por la variación de las características de las especies evaluadas con relación a su altura total, diámetro, volumen de corteza, frecuencia de vasos, longitud de fibras, perfil radial de densidad y contenido de cenizas. Los árboles hospederos presentaron alteraciones en las variables dendrométricas, contenido de pentosanos y cenizas en la madera para ambos materiales genéticos, no siendo observadas variaciones en la densidad básica, dimensión de vasos y fibras, así como en los contenidos de lignina y extractivos de la madera.

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.

RESUMO O presente trabalho teve como objetivo caracterizar a formação de anéis de crescimento no lenho de Khaya ivorensis, bem como, analisar a variação da morfologia dos elementos de vaso, visando ao entendimento do crescimento dessa espécie em plantios experimentais. Para tanto, discos da base de cinco árvores foram coletados e, após o polimento da seção transversal, realizou-se a demarcação dos limites dos anéis de crescimento. Um estudo anatômico da madeira foi realizado com objetivo de caracterizar os anéis e por meio de imagens digitalizadas dos discos foi mensurada a largura dos mesmos. Foi obtida uma série histórica de dados referente ao diâmetro das árvores para estabelecer uma correlação com a largura dos anéis mensurada ao longo dos anos. Os limites dos anéis de crescimento da madeira de mogno africano são demarcados por uma fina camada de parênquima marginal, tendo sido constatada a presença de falsos anéis. Foi observada entre as árvores correlação de crescimento anual significativa de 0,62, sendo o incremento radial do lenho irregular nos primeiros anos (anéis largos e estreitos), com destaque para o 3º e o 11º ano de crescimento, em que foram observados os maiores incrementos, devido a uma tendência biológica de adaptação ao ambiente e pela ocorrência de um desbaste realizado na área de plantio, respectivamente.

ABSTRACT The objective of this study was to characterize the formation of growth rings in Khaya ivorensis wood, as well as to analyze the variation in the morphology of the vessel elements, aiming to understand the growth of this species in experimental plantations. Disks from the bases of five trees were collected, and after polishing the cross-section, demarcation of the growth rings limits was carried out. The anatomical study of the wood was conducted with the purpose of characterizing the rings, and their width was measured by means of scanned images of the disks. A historical series of data was obtained concerning the diameter of the trees to establish a correlation with the width of the rings measured over the years. The growth rings limits of African mahogany wood are demarcated by a thin layer of marginal parenchyma, and the presence of false rings has been observed. Significant annual growth correlation of 0.62 was observed among the trees, being the radial increment of irregular wood in the first years (wide and narrow rings), and highlighting the 3rd and 11th year of growth in which the largest increases were observed due to a biological adaptation tendency to the environment and the occurrence of thinning carried out in the planting area, respectively.

RESUMO O crescimento da demanda mundial por madeira implica na busca de novas espécies de rápido crescimento com potencial silvicultural e, nesse cenário, as espécies nativas como o paricá. Assim, o objetivo deste trabalho foi determinar as propriedades físicas e mecânicas da madeira da espécie Schizolobium amazonicum (paricá). As árvores foram coletadas em plantios comerciais localizados no norte do Brasil, com idades de 5, 7, 9 e 11 anos. Das árvores de cada idade foram obtidas quatro toras no sentido longitudinal das árvores e, posteriormente, um pranchão diametral de cada tora para fabricação dos corpos de prova, os quais foram utilizados para avaliar algumas propriedades físicas e mecânicas da madeira. A densidade básica do paricá reduziu no sentido base-topo e não houve diferença entre as posições radiais, em média, a densidade básica dessa madeira caracterizou-se como baixa. A região próxima da casca apresentou menor contração longitudinal, e também, maior homogeneidade dessa propriedade ao longo do tronco, enquanto para a contração tangencial a menor variação foi encontrada na região próxima à medula. A contração da madeira de paricá foi caracterizada como baixa. A idade influenciou a maioria das propriedades mecânicas, tendo a tora da base os maiores valores de resistência mecânica.

ABSTRACT Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil). Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

RESUMO Este trabalho teve por objetivo avaliar as propriedades tecnológicas de chapas aglomeradas fabricadas com partículas de Acacia mangium e adesivo ureia-formaldeído (UF) mediante adição de tanino comercial de Acacia mearnsii na forma de pó a suas partículas. As chapas foram fabricadas sob diferentes razões de compactação e o efeito destas nas propriedades tecnológicas foi avaliado. Utilizou-se o delineamento inteiramente casualizado no esquema fatorial 4 x 4, sendo quatro porcentagens de adição de tanino em pó às partículas (0, 10, 20 e 30%), após aplicação do adesivo ureia-formaldeído e quatro razões de compactação nominais - 1,39, 1,55, 1,73, e 2,00. Foi utilizado o ciclo de prensagem com pressão de 3,92 MPa e temperatura de 140ºC por 8 minutos. A adição de tanino em pó às partículas encoladas com ureia-formaldeído proporcionou melhoras em algumas propriedades físicas e mecânicas. Os resultados indicam a adição do tanino em pó como alternativa viável de utilização em chapas de partículas, sem necessidade de sua diluição.

ABSTRACT This work aimed to evaluate the technological properties of particleboards manufactured with particles of Acacia mangium and urea-formaldehyde adhesive by addition of powder form commercial tannin of Acacia mearnsii to their particles. The particleboards manufactured under different compaction ratio and the effect of these in the properties of the boards evaluated. It used a completely randomized design in the factorial outline 4 x 4 as follows: four percentages of substitution of powder form tannin to the adhesive urea-formaldehyde - 0, 10, 20 and 30%; and four nominal compaction ratios: 1.39, 1.55, 1.73, and 2.00. The pressing cycle used was 3.92 specific pressure with temperature of 140ºC by 8 minutes. The addition of powder tannin to particles with urea-formaldehyde provided some improvements in the physical and mechanical properties. The results indicate that the addition of tannin powder is a viable alternative of use in particleboards, with no need for dilution.

RESUMO A determinação dos gradientes de umidade é uma das etapas mais importantes na avaliação da qualidade da secagem da madeira. O objetivo geral do trabalho foi estudar a qualidade da secagem natural de tábuas de teca utilizando os gradientes de umidade na espessura e no comprimento. Seis tábuas representativas (40 × 180 × 2.300 mm) foram amostradas de uma pilha de secagem natural sob cobertura, divididas em 30 partes iguais no comprimento e medidas com um medidor elétrico de umidade resistivo, resultando em quatro tratamentos: duas profundidades (1/4 e 1/2 da espessura) e duas superfícies (interna e externa) de medição. Dentre as principais conclusões, a qualidade da secagem natural pôde ser considerada boa, principalmente por dois motivos: i) os gradientes de umidade médios na espessura foram comparáveis àqueles reportados na literatura para secagem artificial de tábuas menos espessas; ii) a amplitude da umidade média entre tábuas (2,5 p.p.) foi satisfatória para um processo de secagem conduzido sem controle das variáveis ambientais. O gradiente de umidade no comprimento foi completamente diferente daqueles reportados na literatura, nos quais o topo de nenhuma tábua apresentou menor umidade do que as porções compreendidas entre os topos.

ABSTRACT The determination of moisture content gradients is one of the most important steps for assessing the quality of wood drying. The general aim of this work was to study the quality of air-dried teakwood boards according to the gradients of moisture content in thickness and length. Six representative boards (40 × 180 × 2,300 mm) were sampled from a stack air-dried under shelter, divided into 30 equal parts in length and measured with a resistance moisture meter, resulting in four treatments: two depths (1/4 and 1/2 thickness) and two surfaces (inner and outer) of measurement. As main results, we can conclude that the air-drying quality can be considered good, mainly for two reasons: i) the average moisture content gradients in thickness were comparable to those reported in literature for kiln-drying of less thick boards; ii) the range of average moisture content among boards (2.5 p.p.) was satisfactory for a drying process carried out without environment control. Length moisture content gradient was completely different from that reported in literature, in which no board tops had smaller moisture content than the parts comprehended in between the tops.

RESUMO Durante o desenvolvimento das árvores, esforços mecânicos são gerados com o intuito de mantê-la em equilíbrio e ereta em resposta a diversos fatores ambientais. Estes esforços são conhecidos como tensões de crescimento e variam na sua distribuição e intensidade nas diferentes espécies do gênero Eucalyptus. Portanto, objetivou-se avaliar a deformação residual longitudinal (DRL) e sua relação com as características de crescimento da árvore, propriedade física e mecânica da madeira de clones do híbrido Eucalyptus urophylla × Eucalyptus grandis com 30 e 35 meses de idade, em plantios florestais na região do Vale do Rio Doce, Minas Gerais, em áreas sujeita a forte ação dos ventos, que tem como consequência o tombamento e até mesmo a quebra dessas árvores. A DRL média foi de 0,086mm, e quando associada as outras características da madeira, as correlações não foram significativas. As características de crescimento das árvores, a densidade básica, o módulo de elasticidade (MOE) e módulo de ruptura (MOR) e trabalho absorvido não foram suficientes para explicar o comportamento da DRL.

ABSTRACT During development and growth of trees, mechanical stresses are generated in order to keep it balanced and upright in response to various environmental factors. These efforts are known as growth stresses and can vary in distribution and intensity across different species of the genus Eucalyptus. Thus, the objective was to evaluate the longitudinal residual strains (LRS) and its correlations with tree growth features, physical and mechanical properties of the Eucalyptus urophylla × Eucalyptus grandis hybrid clones. Trees were 30 and 35 months old, located in forest plantations of Vale do Rio Doce, Minas Gerais, in areas subject to wind action, with damping effect and even the breaking of these trees. The LRS measured with extensometer was on average 0.086mm and when associated with other characteristics of the wood, the correlations were not significant. The growth characteristics of trees, basic density, modulus of elasticity (MOE) and modulus of rupture (MOR), and absorbed work were not enough to explain the LRS behavior.

RESUMO Existem atualmente cinco principais processos de modificação térmica em operação na Europa, que aumentam a estabilidade dimensional e a resistência da madeira à biodeterioração, porém, não são eficientes contra o ataque de térmitas. Na verdade, existe pouca pesquisa a respeito do efeito da modificação térmica da madeira na resistência à biodeterioração por térmitas, sejam subterrâneas ou de madeira seca. O objetivo desta pesquisa foi avaliar o efeito do processo brasileiro de modificação térmica VAP HolzSysteme(r) na resistência da madeira de Eucalyptus grandis ao ataque de térmitas de madeira seca Cryptotermes sp. Para tanto, foram testados cinco tratamentos: madeira não tratada de eucalipto, madeira de eucalipto modificada termicamente a três temperaturas finais (140, 160 e 180°C) e madeira de pinus (controle). O ataque foi avaliado em termos de perda de massa, escore médio das notas do desgaste, número de orifícios e mortalidade das térmitas, de acordo com o método proposto pelo Instituto de Pesquisas Tecnológicas de São Paulo. Semelhante aos processos europeus de modificação térmica, o processo brasileiro VAP HolzSysteme(r) também não foi eficaz para melhorar a resistência da madeira de eucalipto ao ataque das térmitas de madeira seca, pelo menos nas condições avaliadas.

ABSTRACT There are currently in operation five major European industrial processes for wood thermal modification. They improve wood's dimensional stability and decay resistance, but are not efficient against termites attack. In fact, there is little research about the effect of thermal modification on wood resistance to termites, whether subterranean or dry-wood termites. The aim of this study was to evaluate the effect of the Brazilian process of thermal modification (VAP HolzSysteme(r)) on the resistance of Eucalyptus grandis wood to attack by Cryptotermes sp. dry-wood termites. Five treatments were tested: untreated eucalypt wood, thermally modified eucalypt wood at three final temperatures (140, 160 and 180 °C) and pine wood (control). The attack was evaluated in terms of mass loss, mean score of wear grades, number of holes and termites mortality, according to a Brazilian method proposed by the Technological Research Institute of São Paulo. Similarly to the European processes of thermal modification, the Brazilian VAP HolzSysteme(r) was not effective to improve wood resistance to dry-wood termites attack, at least in the evaluated conditions.

O trabalho objetivou realizar a caracterização anatômica e física de hastes adultas do bambu Dendrocalamus giganteus Munro. Assim, foram coletadas quatro hastes e seccionadas em colmos de 2,10 m de comprimento. Das extremidades dos colmos foram obtidos discos de 5,0 cm de espessura, os quais foram transformados em corpos de prova para a caracterização anatômica e física. Foram mensurados o percentual de fibras, de vasos e de parênquima, o teor de umidade, as massas específicas básica e anidra e a retratibilidade. O bambu estudado possui frequência de vasos de 0 a 4 vasos mm–2, média de 2 vasos mm–2, fibras com comprimento médio de 2,72 mm e o parênquima compõe 50,72% do colmo. O teor de umidade foi quantificado em 60%; a massa específica básica, em 0,66 g cm–3; a anidra, em 0,83 g cm–3; a retratibilidade volumétrica, em 15,40%. Observou-se que as características físicas do bambu foram influenciadas pela disposição e pela proporção dos elementos anatômicos.

The work aimed to carry out the anatomical and physical characterizations of adult bamboo rods of Dendrocalamus giganteus Munro. So, four rods were collected and sectioned in culms of 2.10 m long. From the ends of the culms were obtained 5.0 cm thick disks that were transformed into samples for anatomical and physical characterizations. In this study, were measured the percentage of fibers, vessels, parenchyma, the moisture content, the basic specific gravity and oven dry specific gravity and shrinkage. The studied bamboo has 0 to 4 vessels mm–2, with average of 2 vessels mm–2, with average fiber length of 2.72 mm and 50.72% consists of parenchyma tissue. The moisture content was quantified at 60%, the basic specific gravity in 0.66 g cm–3, the oven dry specific gravity in 0.83 g cm–3 and volumetric shrinkage in 15.40%. It was observed that the bamboo physical characteristics were influenced by the layout and anatomical elements proportion.

RESUMO O objetivo do trabalho foi avaliar as características anatômicas e propriedades físico-mecânicas das madeiras de duas espécies de mogno africano (Khaya ivorensis e Khaya senegalensis). Foram utilizadas cinco árvores de cada espécie com 19 anos de idade, proveniente de parcelas experimentais implantadas nas áreas da Reserva Natural Vale, Sooretama, Espírito Santo. Para a característica anatômica foram utilizadas amostras retiradas na posição de transição entre cerne e alburno (cerne periférico). Na avaliação da massa específica básica foram empregadas duas cunhas opostas dos discos obtidos na região correspondente ao diâmetro a altura do peito (DAP), tomado a 1,30 m do solo, e nas posições 0, 25, 50, 75 e 100 % da altura comercial da árvore. Para a retratibilidade foram retiradas 20 amostras obtidas aleatoriamente ao longo do tronco de cada espécie. Os ensaios mecânicos foram realizados em amostras obtidas do pranchão central, ao ser descartada a medula. As espécies foram diferentes quanto ao tipo e frequência de vasos e porosidade. Os raios foram predominantemente multisseriados e heterocelulares e as fibras libriformes. A madeira de Khaya ivorensis possui massa específica baixa, enquanto a de Khaya senegalensis, massa específica média. As duas espécies possuem estabilidade dimensional normal. Em relação as propriedades mecânicas, a madeira de Khaya senegalensis teve os maiores valores para todos os ensaios realizados.

ABSTRACT The objective of this study was to evaluate the anatomical characteristics and wood physical-mechanical properties of two African mahogany species (Khaya ivorensis and Khaya senegalensis). Five trees of each species with 19-years-old, proceeding from experimental parcels in the areas of the Reserva Natural Vale, located in Sooretama, Espírito Santo State, Brazil. For the anatomical characteristics samples were taken at the position of transition between heartwood and sapwood (peripheral heart). In the evaluation of the specific density were used two opposing wedges from discs gotten in the corresponding region to the diameter the height of the breast (DHB), taken the 1,30 m of the ground, and in positions 0, 25, 50, 75 and 100% of the commercial height of the tree. For shrinkage 20 samples obtained randomly throughout the trunk of each species. The mechanical tests were carried through in removed samples of the central large plank, to the discarded the pith. The species were different how much to the type and frequency of vases and porosity. Rays were predominantly multiseriates, heterocellulars and fibers are libriform. The wood of Khaya ivorensis has low specific density and wood of Khaya senegalensis has medium specific density. The two wood species have normal dimensional stability. In relation the mechanical properties, the Khaya senegalensis wood had the biggest values for all the carried through tests.