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The objective of this study was to evaluate the composition of OSB panels created using the Amazonian species Caryocar villosum Aubl., Erisma uncinatum Warm., and Hymenolobium excelsum Ducke. The OSB was produced using a phenol–formaldehyde adhesive at a ratio of 30:40:30 for each layer. Different mixtures of Amazonian wood and Pinus caribaea var. caribaea. were tested. Physical (water absorption and thickness swelling after 2 and 24 h of immersion in water and non-return rate in thickness) and mechanical (internal bond and parallel and perpendicular static bending) tests were performed. The OSB panels composed of wood mixtures absorbed less water after 2 and 24 h of immersion when compared to the OSB produced using pine wood. After 24 h of immersion in water, the T3 panel (40% Pinus caribaea + 40% Hymenolobium excelsum + 20% Caryocar villosum) presented the lowest absorption value. In terms of swelling in thickness at 2 h and 24 h, the panel composed of 100% pine strands showed the highest swelling value, while the T3 treatment exhibited the lowest swelling value at 2 and 24 h, as well as for the rate of non-return in thickness. Regarding mechanical properties, we observed that all panels exhibited similar resistance for both parallel and perpendicular Modulus of Rupture, as well as parallel and perpendicular Modulus of Elasticity, except for the internal bond, where T3 demonstrated the highest resistance. Additionally, some OSB panels met the requirements of the EN 300 standard for OSB panels.

Branch wood presents potential volumetry that may have several applications, and its use may improve forest management efficiency in the Amazon. However, there is a lack of knowledge regarding the properties of branch wood when compared to the stem or what its potential applications might be, considering the possible variability of wood formation in branches. This study aimed to characterize physically and mechanically the branch wood of Dipteryx odorata, Hymenolobium petraeum and Hymenaea courbaril and to compare them with their respective stems. No significant statistical differences were observed for the basic density between the branch and stem woods. The branch wood of Dipteryx odorata and Hymenaea courbaril showed a lower coefficient of anisotropy (1.23 and 1.99, respectively) than the stem wood (1.62 and 2.49, respectively). D. odorata showed similar mechanical properties between the branch and stem, except for hardness, while H. petraeum and H. courbaril branch wood showed lower strengths when compared to the stem wood for all mechanical tests, except for the shear strength test. Branch wood has similar potential uses to stem wood and can be used for non-structural purposes such as small artifacts, decorative items, furniture, tools and panels composed of short, glued pieces.

Relations between crown width and tree height and trunk diameter and tree height were measured for trees of all sizes of six large emergent species (Balizia elegans, Dipteryx panamensis, Hieronyma alchorneoides, Hymenolobium mesoamericanum, Lecythis ampla and Terminalia oblonga) in the lowland tropical wet forest at La Selva, Costa Rica. Thirty to 45 individuals were chosen per species to provide a relatively even height distribution from 1 m up to the maximum encountered height. Among small juveniles, the crown widths of the two species with the smallest leaves and horizontally spreading branches were greater than those of the four large-leaved species. On reaching and exceeding the canopy, all but one species showed pronounced increases in crown width with increasing height. These patterns are linked to leaf size and first branching height in small juveniles and low densities of emergent trees at La Selva and other tropical forests, where crown expansion in all directions enhances light interception under the equatorial sun in trees that are not crowded by neighbours of similar height.

There is still limited understanding of the processes underlying forest dynamics in the world's tropical rain forests, ecosystems of disproportionate importance in terms of global biogeochemistry and biodiversity. Particularly poorly documented are the nature and time scale of upward height growth during regeneration by the tree species in these communities. In this study, we assessed long-term height growth through ontogeny for a diverse group of canopy and emergent tree species in a lowland neotropical rain forest (the La Selva Biological Station, northeastern Costa Rica). Species were evaluated based on annual height measurements of large samples of individuals in all postseedling size classes, over a 16-yr period (>11 000 increments). The study species were seven nonpioneers (Minquartia guianensis, Lecythis ampla, Hymenolobium mesoamericanum, Simarouba amara, Dipteryx panamensis, Balizia elegans, and Hyeronima alchorneoides) and two pioneers (Cecropia obtusifolia and Cecropia insignis). For each species, inherent height growth capacity was estimated as the mean of the five largest annual height increments (from different individuals) in each juvenile size class (from 50 cm tall to 20 cm in diameter). All species showed marked ontogenetic increases in this measure of height growth potential. At all sizes, there were highly, significant differences among species in height growth potential. The two Cecropia species consistently showed the highest observed maximum height increments as smaller juveniles (≤4 cm in diameter). Among the nonpioneers, Simarouba had the highest growth potential across all juvenile sizes. For all species, mean annual height increments in all juvenile size classes were very much lower than the species' potential growth rates and reflected the impacts of frequent periods of zero growth and major height losses from physical damage. Because of the same factors, maximum net height increments declined over increasing measurement intervals (1-15-yr periods). With only one exception (Simarouba amara saplings ≤1 cm in diameter that survived 10 yr), the annual height growth increments of these species showed no significant temporal autocorrelation. For the seven nonpioneer species, we estimated the minimum time required to grow from 50 cm tall saplings to 10 cm diameter trees, based on their greatest net height increments over increasing intervals. Estimated passage times increased from 7-33 yr, when based on maximum 5-yr height increments, to 37-83 yr, when based on maximum net height growth over 15 yr for the six longest studied (nonpioneer) species. Given the erratic height growth trajectories found for these juvenile trees in this 16-yr study, it is clear that much longer term observation is required. Still unknown are the actual growth trajectories that characterize successful regeneration in each of our focal species, how much time successful trees spend as suppressed juveniles, and the number of times they experience and recover from major physical damage.

This research aims to investigate, with the aid of the Brazilian standard NBR 7190, analysis of variance (ANOVA—5% significance) and the regrouping bootstrap technique, the influence of the provenance regions Bonfim, Mucajaí and Claudia on the physical and mechanical properties (twenty properties and 720 determinations) of Angelim-pedra ( Hymenolobium petraeum Ducke.) and to assess the possibility of estimating, via regression models (152 in all), the physical and mechanical properties investigated as a function of apparent density (ρ 12 ) and compressive strength parallel to the grain (f c0 ). The results indicated equivalence in most of the physical and mechanical properties, evidencing the small influence of the tree harvest regions. From the regression models, some were considered significant by ANOVA (at the 5% level of significance), which implies that variations in ρ 12 and f c0 explain variations in the values of the other estimated properties; however, the low precision indicates that it is not feasible to estimate the variables just based on the ρ 12 or f c0 .

To assess the diversity of tropical tree life histories, a conceptual framework is needed to guide quantitative comparative study of many species. We propose one such framework, which focuses on long-term performance through ontogeny and over the natural range of microsites. For 6 yr we annually evaluated survival, growth, and microsite conditions of six non-pioneer tree species in primary tropical wet forest at the La Selva Biological Station, Costa Rica. The species were: Lecythis ampla, Hymenolobium mesoamericanum, Dipteryx panamensis, Pithecellobium elegans, Hyeronima alchorneoides (all emergents), and Minquartia guianensis (a canopy species). The study was based on long-term measurement of individuals from all post-seedling size classes. Trees were sampled from 150 ha of primary forest spanning several watersheds and soil types. To evaluate individuals' microsites we recorded the number of overtopping crowns, forest phase (gap, building, mature), and crown illumination index (an estimate of the tree's light environment). For comparison, we also evaluated the microsites of three species that have been categorized as pioneers (Cecropia insignis, C. obtusifolia) or high-light demanders (Simarouba amara). For the six species of non-pioneers, mortality rates declined with increasing juvenile size class. As a group, these emergent and canopy trees showed a much lower exponential annual mortality rate (0.44%/yr at >10 cm diameter) than has been found for the La Selva forest as a whole. Growth rates increased with juvenile size class for all six species. As adults (trees >30 cm in diameter), all five emergent species showed substantial annual diameter increments (medians of 5-14 mm/yr). Small saplings and adults of all species had significant year-to-year variation in diameter growth, with much greater growth occurring in the year of lowest rainfall. Passage time analysis suggests that all six species require >150 yr for growth from small saplings to the canopy. Evaluation of all nine species revealed four patterns of microsite occupancy by juveniles. Among the non-pioneers, one species pair (Lecythis and Minquartia: Group A) was associated with low crown illumination and mature-phase forest in all juvenile stages. For two species (Dipteryx and Hymenolobium: Group B) the smallest saplings were in predominantly low-light, mature-forest sites, but crown illumination and association with gap- or building-phase sites increased with juvenile size (Simarouba also showed this pattern). Two species (Pithecellobium and Hyeronima: Group C) were strongly associated with gap or building phase as small juveniles (@<4 cm diameter) and again as subcanopy trees (>10-20 cm diameter), but were predominantly in mature-phase sites at intermediate sizes. Juveniles of the two pioneer species (Cecropia: Group D) showed the highest crown illumination and association with gap or building sites. Among the six non-pioneer species, only one aspect of juvenile performance clearly varied according to microsite group. The smallest saplings (@<1 cm diameter) of Groups B and C showed significant mortality differences across a small gradient in crown illumination; neither of the Group A species showed this pattern. Otherwise, juvenile performance was strikingly similar among the six species. All showed a capacity for growth responses to small increases in light, substantial height and diameter increments at higher light levels, equal ability to survive 4-yr periods of no growth, and very low mortality rates at intermediate-to-large juvenile sizes. Species differed significantly in growth rates, but relative differences shifted with tree size and were unrelated to microsite group. These findings do not support prevailing paradigms concerning trade-offs and correlated suites of traits. For non-pioneer tropical trees, life history classification based on generalized concepts such as gap dependence and shade tolerance is inadequate to describe the complex size-dependent patterns of life history differences and similarities that exist among species.

This study investigated the wood surface discoloration due to simulated sunlight of tropical woods native to South America. Wood of jatoba (Hymenaea courbaril L.), massaranduba (Manilkara bidentata A. Chev.), tigerwood (Astronium graveolens Jacq.), angelim amargoso (Vatairea spp.), angelim pedra (Hymenolobium spp.) and angelim vermellho (Dinizia excelsa Ducke) was exposed to a treatment by xenon-arc lamp light simulating outdoor sunlight, for 144 hours. Colour measurement of exposed and non-exposed areas of samples was performed by means of a spectrophotometer measuring in CIEL ∗ a ∗ b ∗ colour system. The resulting wood discoloration was evaluated according to the value of the overall colour change ΔE ∗. Changes of particular parameters (L ∗,a ∗ and b ∗) were also observed during exposure. The wood surface darkened rapidly during the first hours of exposure to simulated sunlight. Later, samples showed only a slight increase in lightness. Within one wood species the colour changes were more significant (higher ΔE ∗) for lighter samples.