Resumo em Inglês:

ABSTRACT Carbon in the juvenile plants contribute significant share to the total carbon stock in forests. A precise estimate of aboveground biomass of the juvenile stages of trees is therefore very important. We developed a generalized allometric biomass model for the prediction of aboveground biomass of the juvenile individuals of Rhododendron arboreum (Sm.). We used data from 66 destructively sampled juveniles of R. arboreum in Gorkha district- one of the mountainous districts in Nepal, for the purpose. Using eight nonlinear functions of various forms (power, exponential, fractional forms), we evaluated several individual-level characteristics, such as size (diameter, height), crown measures (crown ratio, crown width, crown spread ratio, crown index, crown fullness ratio), height-to-diameter ratio (plant bole slenderness), number of branches, wood density, and stand-level characteristics, such as altitude and slope of sites for their potential contributions to the biomass variations of the juvenile individuals. A simple power function with cross-product of the squared-diameter and height as a main predictor and crown spread ratio as a covariate predictor showed the best fit to data (R2 adj=0. 90); RMSE=59.35 g) without substantial trends in the residuals. Our model is site-specific and its application should therefore be limited to those stands which were the basis of this study. Further works on recalibration, validation, and verification of our model using a larger dataset collected from a wider range of species distribution will be more interesting.

Resumo em Inglês:

ABSTRACT Besides being used in the wood industry, copaiba has medicinal properties. However, continuous and excessive extraction both of wood and of oil may impair the regeneration and make the product scarce. It is very important to produce quality seedlings, both for sustainable exploitation and for the recovery of degraded and disturbed areas. The purpose of the present study was to evaluate the initial growth and nutrition of Copaiba seedlings, incorporating organic residues into different classes of soils. The treatments were disposed in a design of entirely randomized blocks using the 5x4 factorial scheme, with four organic residues (rice husks in natura, carbonized rice husks, goat manure, carnauba residue), plus a treatment with soil only and four classes of soil (Latossolo Vermelho-Amarelo, Neossolo Quartzarênio, Gleissolo Háplico e Argissolo Vermelho-Amarelo), with four repetitions. At 90 days, the morpho-physiological variables of the seedling and macronutrient contents of the aerial part were evaluated. As to the morpho-physiological variables, the carnauba residue was outstanding among the residues tested in the present study. There was an increase in the quantities of P, K, Ca and Mg in the aerial part of copaiba seedlings resulting in the combination between the organic residues and the soil classes.

Resumo em Inglês:

ABSTRACT Artificial Intelligence has been an important support tool in different spheres of activity, enabling knowledge aggregation, process optimization and the application of methodologies capable of solving complex real problems. Despite focusing on a wide range of successful metrics, the Artificial Neural Network (ANN) approach, a technique similar to the central nervous system, has gained notoriety and relevance with regard to the classification of standards, intrinsic parameter estimates, remote sense, data mining and other possibilities. This article aims to conduct a systematic review, involving some bibliometric aspects, to detect the application of ANNs in the field of Forest Engineering, particularly in the prognosis of the essential parameters for forest inventory, analyzing the construction of the scopes, implementation of networks (type - classification), the software used and complementary techniques. Of the 1,140 articles collected from three research databases (Science Direct, Scopus and Web of Science), 43 articles underwent these analyses. The results show that the number of works within this scope has increased continuously, with 32% of the analyzed articles predicting the final total marketable volume, 78% making use of Multilayer Perceptron Networks (MLP, Multilayer Perceptron) and 63% from Brazilian researchers.

Resumo em Inglês:

ABSTRACT Micromorphological characters including surface, length and width of seeds were recorded for 19 species of Eucalyptus (Myrtaceae) using stereomicroscope to determine the importance of seed morphological characters as an additional tool for identification.With the aim of selecting and valorizing abiotic-stress-tolerant species with landscape and industrial values and would be a potential solution for valorizing dry arid area and development of land degradation, we launched the assessment of the performance of five Eucalyptus species (E. torquata, E. sargenti, E. gillii, E. gomphocephala x E. cornuta and E. microtheca) under salinity and osmotic potential constraints. Several NaCl concentrations (0, 3, 6, 9, 12, and 15 g.L-1) and several osmotic potentials (0, -0.03, -0.1, -0.7, -1 and -1.6 MPa) were applied to seeds cultivated in petri dishes for a period of one month. Germination rates, means time of germination and coefficent of velocity were evaluated to better understand the salt stress and osmotic potential effect on germination. Univariate and multivariate analyses were used to identify the major characteristics pertaining to salinity tolerance. Modeling of germination under both constraints saline and osmotic stress is carried out to predict the behavior of the species. The hybrid E. gomphocephala x E. cornuta was more tolerant to salt stress (15 % at 12 g.L-1) and osmotic potential (61 % at -1.6 MPa) than the others species of Eucalyptus; it showed a higher germination percentage under all tested potentials, when compared to the not hybrid species of Eucalyptus. Our analyses of seeds morphology revealed that the observations shown diversity of morphological characters in seeds. Area, length and width of seeds vary significantly between species of Eucalyptus. Micromorphological characters can provide basis for classification and delimitation of genus Eucalyptus.

Resumo em Inglês:

ABSTRACT In countries like Costa Rica, there is an interest in developing wooden trusses in a versatile and light way. However, there is a key aspect in the behavior of truss connections in this product. Therefore, the present study determines the structural behavior of the truss connections and the displacement, the resistance, the stiffness values and the failure mode of truss connections made with Gmelina arborea and Tectona grandis timber for angles of 0° and 90°; and three types of truss connectors (metal plates, screws and nails), subject to tension and compression loads. The results showed that metal plates show the highest load values with respect to the nails and screws in both species. Likewise, in the design and critical displacement stress, metal plates surpass the nails and screws in both species; and in the two angles. From these stress values, we proposed a model for the prediction of the stiffness for the truss connections of the intermediate angles (30°, 45° and 60°) and the test showed that the prediction was low, the bias was 3%.

Resumo em Inglês:

ABSTRACT Determination of leaf nutrient concentrations is traditionally performed by carrying out destructive procedures, requiring laboratory chemical analysis, specialized equipment, and skilled labor. However, technological advances in recent years have now made it possible to analyze leaf nutrient concentrations using non-destructive methods such as leaf reflectance. This study evaluates the relationship between leaf reflectance and nutrient concentration in order to develop and apply nutrient indices by proximal sensing data in plantations of Eucalyptus. Two experiments were carried out for the development, application and validation of nutrient indices in Eucalyptus stands in the municipalities of Lassance and Três Marias, Minas Gerais state, Brazil. Study I was undertaken in Eucalyptus stands with 25 months old and, three clones. Leaves from the lower crown were visually classified into five color patterns using the Munsell chart for plant tissues. Study II was carried out in commercial stands of a hybrid of Eucalyptus urophylla ST Blake, whith 9, 12, 15 and 25 months old. Analysis revealed strong relationships between leaf nutrients and leaf reflectance in the visible and near infrared regions (400 - 900 nm) of the light spectrum. Correlation analysis between leaf reflectance and nutrients can be useful in an exploratory analysis of leaf nutrient concentration. Some nutrient indices developed (NI, PI, SI and CuI) provided satisfactory estimates of leaf nutrient concentration in Eucalyptus stands. The nutrient indices developed in this study may be a useful alternative to laboratory chemical analysis.

Resumo em Inglês:

ABSTRACT The classification of sites through curves of Site Index allows to predict the yield of the planted forests at a certain age of the stand and to plan cultural treatments. The goal of this research was to compare linear and non-linear models of fixed effects vs. mixed non-linear models to estimate the site index in plantations of Prosopis alba var Griseb in the irrigated area of the province of Santiago del Estero, Argentina using the guide curve method. The data used comes from temporary plots, permanent plots and growth data from the stem analysis of selected individuals based on their greater growth in height within the sampled areas. The registered variable for the evaluation of the site was the dominant Height (HD), defined as the average height of the 100 thickest trees per hectare. Considering that the source of data from repeated measurements on the same subject implies the presence of correlation and/or heteroscedasticity, it was proposed to evaluate statistical models that allow to properly representing the structure of the variance-covariance matrix, improving the accuracy in the adjustment. From the analysis of the results, it appears that the models non-linear mixed models have had better performance in the adjustment of the Site Index than linear and non-linear models of fixed effects. The most accurate model (smallest AIC and BIC) in the site index estimation was the mixed non-linear regression model of “Gompertz”, with structure of composite symmetry correlation and exponential heteroscedasticity.

Resumo em Inglês:

ABSTRACT The aim of this research was to investigate sugarcane bagasse (SCB) particleboards, using two kinds of particles, from pith and fibers, reinforced with cellulose nanocrystals (NCC). The NCCs were dispersed in the adhesive urea formaldehyde (UF) using a sonificator in two proportions (0 and 1%). The NCCs and UF were applied in the SCB particles using a rotary blender. The particleboards were produced in three layers using two kinds of particles: pith and fibers. After dispersion of the adhesive, the mixture was compressed to produce the particleboards, which were characterized by physical, mechanical and thermal properties. The anatomical and chemical features relating to pith and fiber were very similar. The particleboards made with and without NCCs did not differ statistically for most properties: modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) thermal conductivity (TC), and the volume heat capacity (VHC). Particleboards made only with fibers and without NCCs showed higher internal bond (IB). In the other hand particleboards made only with fibers in the face and pith in the core (without NCCs) showed lower thickness swelling after 24 hours (TS24h). Probably, the NCCs did not improve the particleboards performance, because less links were available for SCB to interact with the adhesive. For the others properties the particleboards made with pith and fibers did not showed statistical difference (MOE, MOR, TC, WA, TC and VHC), demonstrating that separation of pith and fiber are not significant and does not affect the final properties of particleboards.

Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate operators’ posture and repetitive motions in the mechanized wood harvesting operations, aiming comfort, safety, and health of forest operators. The study was carried out in the clearcutting of pine stands located in Paraná State, Brazil. Data were obtained in tree cutting operations with feller buncher and wood processing with harvesters, in which three operators in each machine were filmed during their workday. The typical postures were evaluated by Rapid Whole-Body Assessment (REBA) and Rapid Upper-Limb Assessment (RULA) methods, while repetitive motions were evaluated by Latko, Silverstein and Strain Index (SI) methods. The results showed the feller buncher operators remained long period seated in static position, with fists turning outside the neutral line and without pauses for recovery, although REBA and RULA methods had identified low postural risk. In wood processing operation, the spinal column and neck were the most affected body parts, presenting medium postural risk and the need for investigations and quickly changes by REBA and RULA methods, respectively. Besides that, wood harvesting operations with feller buncher and harvester were classified as high repeatability, showing more than 30 thousand repetitive motions in a workday, indicating high risk of Repetitive Strain Injuries (RSIs) and Musculoskeletal Disorders (MSDs) in the operators. Therefore, it is concluded the ergonomic measures are necessary to improve operators’ comfort and health.

Resumo em Inglês:

ABSTRACT Aiming at contributing to the knowledge of the biology and propagation of Cariniana pyriformis Miers, a native species with high timber and ecological attributes, ripe fruits were harvested. Initially, in 400 seeds and 320 fruits, the size, fresh mass, seed water content, number of seeds per fruit, number of seeds per kilogram and fruit color were assessed. Then, a homogenous seed sample was immersed for 24 hours in five doses (0, 250, 500, 750 and 1000 mg.L-1) of gibberellins (GA3) and cultivated in a greenhouse. For this, a completely randomized design was adopted with six replications of 25 seeds each. Fruits and seeds showed values, on average ± standard deviation, of 76.1 ± 11 mm and 48.1 ± 8.2 mm in length, and 49.6 ± 5 mm and 7.2 ± 0.7 mm of width, respectively, with 62.3 ± 22.3 g of fresh mass per fruit and 13 ± 3.1 seeds per fruit. One kilogram corresponded on average to 6715 seeds with 11% water content. In the greenhouse, emergence speed index and emergency percentage of seedlings increased as the GA3 dose increased, allowing a more concentrated emergency process in a shorter period. Highest variation was found for fresh mass per fruit (CV= 35%) and number of seeds per fruit (CV= 24%). Immersion in 1000 mg.L-1 in GA3 for 24 hours triggers seedling emergency in C. pyriformis (approx. 71%), and then it is recommended for plant propagation, since the treatment accelerated and synchronized seedling emergency.

Resumo em Inglês:

ABSTRACT The soil properties reported in areas with different management provide useful information about the systems’ operation, state of conservation and resilience. In this way, this study evaluated physical properties and organic matter dynamics of soil under different plant covers in seven areas consisting of: five areas under ecological restoration (REC1 to REC5), an areas with native vegetation (MATA) and a sugarcane crop area (SC), all located in State of Mato Grosso do Sul, a transition area between the Cerrado and Atlantic Forest biomes. Samples were taken at the 0-10 and 10-20 cm layers and were analyzed for soil density (Ds), macroporosity (Ma), microporosity (Mi), total porosity (PT), weighted mean diameter (DMP), aggregate stability index (IEA), and the particle sizes of organic matter. There were no differences in DMP between the areas, however, sugarcane crop area and areas under ecological restoration (REC 1, 3 and 4) had high values of density and microporosity and low contents of the fractions of organic matter, which can promote a greater restriction to the root development of plants. Among the areas under restoration, REC1 and REC5 presented physical conditions with higher similarity to the native vegetation area. Changes in the physical soil properties and parameters such as Total organic carbon (COT), confirmed that the restoration practices applied improved the soil quality.

Resumo em Inglês:

ABSTRACT Proposing technological innovations in the investigation of the structure and behaviour of wood is important to optimize its use. The assimilation of methods diffused in other areas, such as particle image velocimetry (PIV), can allow a rich range of information for different aspects. The aim of this study was to estimate the Young’s modulus using the PIV technique, independently of the wood density. The Young modulus value was obtained by universal testing machine, transversal vibration and PIV technique. Cedrela spp. and Eucalyptus cloeziana wood specimens were analyzed and their Young modulus were compared and correlated. The PIV technique presented mean Young’s modulus values statistically equal to those of the universal testing machine. The standard error of prediction from PIV approach was 0.46 and 0.97 GPa for Young’s modulus estimates for Cedrela spp. and Eucalyptus cloeziana wood, respectively.

Resumo em Inglês:

ABSTRACT Increasing population, mobility and requirements of human beings have significant effects on the dynamics of land use and land cover. Today, these impacts need to be understood and analyzed for the applicability of decision support systems, which are an important tool in the management of natural resources, urban and rural areas. The aim of this study is to detect the temporal and spatial changes of land cover and human population, in northwest Turkey. For this purpose, using satellite images of 1997-2007 and 2017 years’ land cover was estimated for 2027 by ANN (Artificial Neural Network) approach. Kappa values are 93%, 87% and 95% for 1997, 2007 and 2017 respectively. As a result, learning success was 80.6%, and correctness validation value was 90.1% for 2027 simulation. In parallel, the spatial analysis of the population was conducted for 2000-2007-2017. Using the exponential rate of change; the population was predicted to increase by concentrating on the urban area and the rural areas surrounding the urban (with a rate of 2.019%) for 2027. According to the results; rural population, urban population, forest, and built-up areas is estimated to increase by 4.14%, 5.58%, 2.72%, and 0.77% respectively from 2017 to 2027, while the agricultural and water area is estimated to decrease by 3.47% and 0.02% respectively. Consequently, the observation of population movements and the use of the ANN approach in simulations could be suggested for the success of planning in forest and land management.

Resumo em Inglês:

ABSTRACT Leaf-cutting ants are the main pests in forest plantations. The most commonly used chemical control for the ants is toxic bait. However, the active ingredients in these baits have been restricted by forest certification organizations, justifying the search for new active compounds to control these insects. Thus, this work aimed to evaluate the formicidal activity of alkaloid fractions from the roots, stems, branches and leaves of Psychotria hastisepala and Psychotria leiocarpa (Rubiaceae) against Atta sexdens Forel, 1908 (Hymenoptera: Formicidae). The alkaloid fractions were obtained from the crude methanolic extracts of P. hastisepala and P. leiocarpa by the acid-base extraction method employing liquid-liquid partitions. The fractions, previously solubilized in propanone, were applied topically to the pronotum of worker ants. Bioassays were conducted in a completely randomized design, with six replicates of each treatment and 10 ants per replicate. Insect survival was assessed daily for 21 days. The median lethal time was estimated by Weibull models. The root fractions from P. hastisepala presented the highest toxicity, followed by those from the branches, stems and leaves. Among fractions from P. hastisepala roots, the most toxic were a fraction that apparently is rich in lipophilic compounds and nonbasic alkaloids and a fraction that is likely rich in quaternary benzophenanthridine alkaloids, protopine alkaloids and tertiary bases. Psychotria leiocarpa fractions were not toxic to this insect. Psychotria hastisepala is potentially useful for the development of new products for A. sexdens control.