Resumo em Inglês:

Abstract Some species of the Lauraceae family produce seeds that are generally sensitive to desiccation, which makes them difficult to store. The objective of this study was to characterize changes in seed quality of C. aschersoniana from two lots, as well in the physiological and cellular aspects during 12 months of storage. Seeds were stored with their original moisture content (MC) or after pre-drying to 35% MC in a cold chamber (5 °C) at a relative humidity of 40%. Seeds were sampled and tested at time 0, 3, 6 and 12 months of storage regarding to moisture content, germination and ultrastructural features. The seeds were dispersed with dormancy that was overcame by the cold storage condition and the reserves in undried seeds were partly consumed during storage. Both undried and pre-dried seeds remained viable for at least 12 months.

Resumo em Inglês:

Abstract The aim of this study was to model the height and diameter distributions and the height-diameter relationship in an old unmanaged Eucalyptus stand in southeastern Brazil. The diameter at 1.30 m above soil (DBH) and total height (H) of all 469 trees in the stand were measured. For the DBH-H modeling, besides testing various traditional linear and nonlinear models, the inclusion of diameter class as random effect was also testes. For the DBH and H distributions modeling, seven probability density function were tested. The DBH-H relationship was best represented by the Henriksen’s linear model. Including diameter classes as a random effect did not improve estimates. The three parameters Weibull distribution was the best model to describe the diameter and height in old and unmanaged planting of Eucalyptus. The DBH distribution showed the highest frequency of individuals in lower diametrical classes, influenced by competition, while H had distribution similar to normal.

Resumo em Inglês:

Abstract The aim of this work was to verify the effect of size classification on the physical and physiological quality of Eucalyptus spp. seeds to optimize the selection for covering. The seeds were separated in sieves with six size classes: 850, 710, 600, 500, 425 µm, and a non-perforated bottom (< 425 µm). Were evaluated the sieve retention, purity, weight of a thousand seeds, germination, and first count of germination. Sieve classification is effective for the separation of materials according to the best physical and physiological qualities. E. grandis seeds from the 710 µm sieve, E. robusta from the 850 µm sieve, and E. urophylla from the 710 and 850 µm sieves can be selected for covering, as they present maximum physical and physiological quality. For the three species, the smallest materials, retained in the 500, 425, and bottom <425µm sieves, must be discarded due to low purity and germination potential.

Resumo em Inglês:

Abstract Tree plantation is the most used technique for ecological restoration, although passive restoration requires a lower investment of resources. This research aimed to compare the composition and structure of the community of regenerant plants in areas under restoration through Assisted Natural Regeneration and mixed native Tree Planting, in the same area. We randomly placed 12 plots of 100 m2 each and sampled all the regenerating individuals found within them. We compared both restoration methods regarding growth pattern, dispersal syndromes, and successional groups. In both methodologies, trees and shrubs were the most abundant growth forms. The pioneer successional class was the most abundant in number of individuals for both treatments. We concluded that the two restoration methods allowed the regeneration of native species. We propose that Assisted Natural Regeneration is a viable restoration strategy, capable of boosting the initial processes of the community, especially in a matrix surrounded by remaining forests.

Resumo em Inglês:

Abstract Invasive exotic grasses are among the biggest obstacles to the success of reforestation projects. The aim of this study was to evaluate the efficiency of the crowning with cardboard in suppressing the grasses Urochloa humidicola and Megathyrsus maximus aiming its use in reforestation areas. A field experiment was installed in a completely randomized design with two treatments consisted of crowning with cardboard and without crowning (control). The crowning with cardboard caused a progressive reduction of the biomass and was effective in causing senescence of both grasses in 80% or more of the crowning area between 20 and 50 days after the crowning (F test; p<0,05). These results demonstrate the effectiveness and potential of using the crowning with cardboard to control alien grass species in reforestation areas. This method brings as an innovation the possibility of placing cardboard directly on the grass after mowing, allowing greater simplicity and lower operating cost.

Resumo em Inglês:

Abstract Heat treatment aims to reduce the compression stresses generated during the panel production, improving its dimensional stability and providing greater resistance to attack by xylophagous organisms, despite decreasing the mechanical properties. This work aimed to evaluate the physical-mechanical properties of medium density particleboard (MDP) of Eucalyptus sp. subjected to post-heat treatment with two temperature levels (200 and 260ºC) and two periods (5 or 10 minutes). The apparent density, water absorption and thickness swelling (TS) after 2 and 24h, internal bonding, MOE and MOR in static bending were evaluated. The post-heat treatment at 200 °C for 5 minutes was the most efficient, improving the TS, with smaller reductions in the mechanical properties. The temperature had a greater influence in the first hours of immersion in water (TS2h), while for a longer period (TS24h) the heat treatment time was more effective. The temperature influenced the mechanical properties more negatively than the heat treatment time.

Resumo em Inglês:

Abstract Cinchona officinalis is an important species from the Andean cloud forest that has a low regeneration rate in natural populations. In vitro regeneration of C. officinalis has been successfully established but somaclonal variation was not evaluated. The regeneration pathway and the number of subcultures on somaclonal variation were evaluated using six ISSR primers that amplified 58 loci of Inter Simple Sequence Repeats (ISSR). A dendrogram based on Jaccard´s genetic distance between the subcultures and the donor plant was produced. The results show that indirect shoot regeneration induces somaclonal variation, in the presence 2,4-Dichlorophenoxyacetic acid (2,4-D) in combination with kinetin and 6-Benzylaminopurine (BAP). In combination with 1-Naphthaleneacetic acid (NAA) or with Indole-3-butyric acid (IBA), BAP produces genetically stable explants. The highest proliferation rate was achieved using BAP and IBA. The present research study suggests avoiding the use of 2,4-D when C. officinalis is propagated for reintroduction and restoration projects.

Resumo em Inglês:

Abstract The baru (Dipteryx alata Vogel), is fruit tree displaying economic, environmental, industrial and food importance. The objective of this study was to adapt to the tetrazolium test methodology to baru seeds and evaluate the physiological quality of seeds stored for 12 months at 10 and 20 ºC, using X-ray images as a toll for detection damage throughout the storage period while also carrying out germination, emergence and electrical conductivity tests. Baru seeds remained viable for 12 months of storage, albeit with a small decrease in vigor after nine months. The applied tetrazolium test methodology was efficient in determining internal seed damage. The pre-soak time for the tetrazolium test and solution concentration was 24 hours and 0.05%. No changes in seed morphology and radiographic images were observed during the storage periods, regardless of the assessed temperature. The X-ray test enabled a precise visualization of internal baru seed structures.

Resumo em Inglês:

Abstract Coffee crop in Brazil is typically grown as a monoculture. However, we hypothesized that agroforestry system is favorable association for arbuscular mycorrhizal fungi (AMF), affecting its community structure and potentially impacting crop productivity and agroecosystem health. This study evaluated how the microclimate, soil depth, macauba field spacing and distance between coffee plants and palms affect the structure of the AMF community. The structure of the AMF community was influenced by the soil depth, microclimate features, soil moisture, maximum air temperature, and photosynthetically active radiation (PAR). The distance at which coffee-macauba influences ecological diversity indices of AMF, and higher diversity are related to the proximity between plants. AMF diversity (Richness and Shannon) in the agroforestry system exceeded that observed in the full-sun coffee in the 0-20 soil depth layer. Our results showed that the microclimate, soil depth, plant density, and distance between coffee from macauba affected the AMF community structure.

Resumo em Inglês:

Abstract Classifying seeds in terms of desiccation tolerance is the first step in determining the potential and most appropriate conditions for storage. This study aimed to characterize the tolerance to desiccation of Diospyros inconstans seeds from fruits at different maturity stages. Germination tests were performed in a 3 x 6 factorial scheme, with seeds from fruits at three maturity stages (unripe, intermediate and ripe) and six moisture contents (initial, 20%, 15%, 10%, 5% and 2.5%). Accumulated germination was analyzed by the nonlinear models Gompertz and Logistic. The percentages of normal seedlings and unviable seeds were subjected to analyses of variance and regression. Diospyros inconstans seeds are tolerant to desiccation. The tolerance is higher in seeds from fruit with intermediate maturation than unripe and ripe fruits.

Resumo em Inglês:

Abstract This study aimed to evaluate the phytotoxic activity of aqueous extracts of species from the Cerrado of Mato Grosso on the germination and initial development of lettuce seedlings, as well as to determine the chemical composition of the extracts. The species studied were: Davilla elliptica, Combretum laxum, Himatanthus obovatus, Diteryx alata, Curatella americana, Qualea grandiflora, Aspidosperma macrocarpon, Caryocar brasiliense, Pleroma candolleanum and Miconia albicans. Fourier Transform Infrared Spectroscopy (FTIR) and Thin Layer Chromatography (TLC) techniques were used to identify functional groups and chemical compounds. The extracts of the species D. elliptica, C. laxum, C. brasiliense and Q. grandiflora showed greater phytotoxic activity on the germination of lettuce seeds which varied between 96 and 17%. The presence of compounds such as: phenols, alkaloids, flavonoids and terpenes with phytotoxic properties was confirmed.

Resumo em Inglês:

Abstract The biotic factors in tropical lowland forests, especially vegetation, are essential for the sustainable management of forest products. The study aimed to investigate the species richness and diversity of trees in Buah Hitam habitats, and study the tree communities formed by tree species by collecting the data from the habitats of Buah Hitam in Wondama Bay, West Papua, Indonesia viz. primary forest, secondary, and the garden with plots 9, 9, and 8 respectively. The species richness and diversity were higher in the primary forest than that in the secondary and garden. Tree communities indicated that the primary forest differed from the secondary and garden. The habitat types have been shaped as a result of anthropogenic activities for decades. This finding is necessary to set the consensual programs by the government and local people particularly in conservation and sustainable management for the three habitats.

Resumo em Inglês:

Abstract The use of tropical species in forest plantations is an alternative to supply the demand of good quality wood. However, information regarding the performance of planted tropical species is scarce. The aim of this study was to provide an assessment of the lumber potential of Cariniana legalis (“jequitibá-rosa”), Zeyheria tuberculosa (“ipê-felpudo”) and Cordia trichotoma (“louro-pardo”) in a forest plantation. Three trees per species were sampled at age of 50 months, planted in a mixed stand with 2 x 4 m spacing in Porto Seguro, Bahia, Brazil. We assessed characteristics of the trees, the logs, lumber yield, and partial volumetric shrinkage of wood. Total volumetric shrinkage of ipê-felpudo, jequitibá-rosa and louro-pardo would be around 12.80%, 13.40% and 11.58%, respectively. Among the three species analyzed, louro-pardo had the best performance, followed by ipê-felpudo, while jequitibá-rosa had the worst performance. All species had good performance regarding log quality and dimensional stability of wood.

Resumo em Inglês:

Abstract In this study, we surveyed termites in Thailand and characterized the mounds they built in mixed deciduous forests. We analyzed soil samples from termite mounds for moisture, electrical conductivity, temperature, pH, and soil texture. Three species of wood-feeding termites were identified, including Globitermes sulphureus (47%), Microcerotermes crassus (32%), and M. distans (21%). The sizes of mounds were the largest for G. sulphureus, followed by M. crassus and M. distans. The characteristics of termite mounds were slightly acidic sandy-clay soils for G. sulphureus, slightly acidic sandy-clay-loam soils for M. crassus, and slightly basic sandy-clay soils for M. distans. The PCA revealed three groups of mound individuals without a clear separation of termite species. In future study, it is suggested to use more samples and other soil parameters such as clay minerals of different particle sizes.

Resumo em Inglês:

Abstract Based on a systematic review, 19 case studies were selected, focusing on the production of biochar through pyrolysis of five lignocellulosic biomasses (olive husk, beech wood, corncob, spruce wood, and hazelnut shell), under constant pressure (0.1 MPa) and temperature from 650.2 to 973.0 K. Interactions between process variables (temperature, residence time of the vapor phase and heating rate), biomass chemical composition variables (lignin, holocellulose, ash, carbon, nitrogen, oxygen and hydrogen content) and biochar yield-CY were evaluated by Pearson’s correlation matrix and Principal Component Analysis-PCA. Strong correlations (|r| ≥0.75, p<0.05) were found for lignin and CY (0.78); carbon and CY (0.76); nitrogen and CY (0.77). Three variables of biomass chemical composition were the most important ones for the first principal component-PC1; process variables (heating rate and the vapour residence time) were the most important ones for the second principal component-PC2. Experiments with hazelnut shell as feedstock were associated with higher CY.

Resumo em Inglês:

Abstract African mahogany is the common name of species from the Khaya genus and yields high value timber. It is planted in monocultures and agrosilvipastoral systems in Brazil since the 90’s. Here we relate the taxonomic identification of the most planted African mahogany species in Brazil, changing from Khaya ivorensis A. Chev. to K. grandifoliola C. DC. Currently we estimate there is circa 50 thousand hectares of plantations in Brazil, half concentrated in the Southeast region, with the most planted species K. grandifoliola, followed by K. senegalensis (Desr.) A. Juss.