ABSTRACT Modeling diameter distribution in natural forests is an important tool for understanding the native woody species dynamics, supporting decision-making for degraded lands management and restoration. Therefore, this work aimed to fit probabilistic density functions to evaluate the diameter structure of three tree species with economic interest, such as Campomansesia xanthocarpa Marl. Ex. O. Berg, Piptadenia gonoacantha (Mart.) J.F. Macbr. and Zeyheria tuberculosa (Vell.) Bureau ex Verl., in a Semideciduous Seasonal Forest fragment at São Paulo State, Brazil. The data came from 83 temporary plots of 10 m x 20 m systematically distributed along 164 ha. Log-normal, Gamma, and Weibull functions were fitted to the three species using the fitdistrplus-package in the R program. Kolmogorov-Smirnov's adherence test was used to evaluate the fits at a 5% probability level. The functions were selected employing Akaike's Information Criterion (AIC) and Schwarz's Bayesian Information Criterion (BIC), in addition to a graphical analysis of the fitted functions. The results indicated that the three species diameter structure is positively asymmetric, representing the exponential pattern, representing continuous natural regeneration. AIC and BIC statistics indicated the Log-normal function to describe the diameter distribution of C. xanthocarpa and Z. tuberculosa, while the Gamma function was the most appropriate for P. gonoacantha. For the three species, the graphical analysis showed the Gamma function results in the best fit without tendency for estimating frequency density per diameter class.

RESUMO A modelagem da distribuição diamétrica em florestas naturais é uma ferramenta importante para compreender a dinâmica de espécies nativas lenhosas, auxiliando na tomada de decisão para o manejo e a recuperação de áreas degradadas. Dessa forma, o objetivo deste trabalho foi ajustar funções de densidade probabilística para avaliar a estrutura diamétrica de três espécies arbóreas de interesse econômico, como Campomansesia xanthocarpa Marl. Ex. O. Berg, Piptadenia gonoacantha (Mart.) J.F. Macbr. e Zeyheria tuberculosa (Vell.) Bureau ex Verl., em um fragmento de Floresta Estacional Semidecidual no estado de São Paulo, Brasil. Os dados foram provenientes de 83 parcelas temporárias de 10 m x 20 m distribuídas sistematicamente ao longo de 164 ha. As funções Log-normal, Gamma e Weibull foram ajustadas para as três espécies por meio do pacote fitdistrplus no programa R. O teste de aderência de Kolmogorov-Smirnov foi aplicado a 5% de probabilidade para avaliar os ajustes. As funções foram .selecionadas por meio do Critério de Informação Akaike (AIC) e do Critério de Informação Bayesiano de Schwaarz (BIC), além da análise gráfica das funções ajustadas. Os resultados indicaram que a estrutura diamétrica das três espécies é assimétrica positiva, as quais apresentam o padrão exponencial, sugerindo uma regeneração natural contínua. As estatísticas de AIC e BIC indicaram a função Log-normal para descrever a distribuição diamétrica de C. xanthocarpa e Z. tuberculosa, enquanto a função Gamma foi a mais adequada para P. gonoacantha. Para as três espécies, a análise gráfica mostrou que a função Gamma resultou no melhor ajuste, não apresentando tendências nas estimativas da densidade de frequências por classe de diâmetro.

ABSTRACT Optimizing resources is essential for the excellence and competitiveness of a forestry company. In this context, this study evaluated the productivity and quality of eucalyptus wood processing for energy purposes. The study was conducted in a forestry company in Paraná State in stands of Eucalyptus urophylla × Eucalyptus grandis and Eucalyptus saligna clones named stands 1 and 2, respectively, with an age of 7 years old. The trees were processed with a harvester and included the following four stem diameter limits for pulp production and co-products for energy purposes: 8, 10, 12, and 14 cm; and pulp logs with a length of 7.20 m. The technical analysis of the operation determined the average operating cycle times, utilization rate and machine productivity. In addition, a quality analysis determined the stem diameter limits for production of the co-products and the lengths of the pulp logs; the limit diameters were compared by the Tukey’s test, and the stands by the Student’s t-test (α ≤ 0.05). The results showed that the processing time decreased with increasing limit diameter, with the highest values being in stand 1 due to the higher number of branches and forked trees. The processing logs at 10 cm limit diameter provided higher harvester productivity, with 59.5 m³ PMH-¹ and 62.2 m³ PMH-¹ in stands 1 and 2, respectively. Furthermore, the best quality in the limit diameter measurement was obtained at 10 cm. Thus, the effects of forest stand and limit diameters on processing and operation quality were evident.

RESUMO A otimização dos recursos é essencial para a excelência e competitividade de uma empresa florestal. Neste contexto, o estudo avaliou a produtividade e a qualidade do processamento da madeira de eucalipto para fins energéticos. Para isso, o estudo foi conduzido em uma empresa florestal no estado do Paraná, em povoamentos de clones de Eucalyptus urophylla × Eucalyptus grandis e Eucalyptus saligna denominados povoamentos 1 e 2, respectivamente, com idade de 7 anos. O processamento das árvores com o harvester incluiu quatro limites de diâmetros do fuste para a produção de celulose e coprodutos para fins energéticos, sendo: 8, 10, 12, e 14 cm; e, toras para celulose com um comprimento de 7,20 m. A análise técnica da operação determinou os tempos médios do ciclo operacional, a taxa de utilização e a produtividade da máquina. Ao passo que, a análise de qualidade determinou os diâmetros limite do fuste para a produção dos coprodutos e os comprimentos das toras para celulose, sendo que, os diâmetros limite foram comparados pelo teste de Tukey e os povoamentos pelo teste t de Student (α ≤ 0,05). Os resultados mostraram que o tempo de processamento diminuiu com o aumento do diâmetro limite, com os valores mais elevados no povoamento 1, devido ao maior número de galhos e de árvores bifurcadas. As toras processadas no diâmetro limite de 10 cm proporcionaram uma maior produtividade do harvester, com 59,5 m³ PMH-¹ e 62,2 m³ PMH-¹ nos povoamentos 1 e 2, respectivamente. Adicionalmente, a melhor qualidade na medição do diâmetro da ponta foi obtida a 10 cm. Portanto, os efeitos dos povoamentos florestais e dos diâmetros limite na qualidade de processamento e operação eram evidentes.

Resumen El conocimiento detallado de la estructura de las plantaciones de teca es necesario para los planes de gestión sostenible. La integración de variables de teledetección con la modelización geoestadística en plantaciones de teca ha sido poco estudiada y, por tanto, el objetivo consistía en modelizar la distribución espacial de las variables del rodal de teca, incorporando covariables. El estudio se realizó en plantaciones de teca de 19 años en Brasil con 213 hectáreas en el espacio inicial de 3 m x 3 m. Se asignaron parcelas georreferenciadas de 900 m² y se obtuvieron las variables forestales después del clareo. Los índices de vegetación se calcularon a partir de operaciones aritméticas ejecutadas entre las bandas de imágenes Landsat. La interpolación de las variables forestales se procedió por el método geoestadístico univariante de kriging ordinario, así como por el método multivariante de kriging con deriva externa, considerando las variables de teledetección como covariables. El análisis estadístico de las variables de teledetección muestra una discreta correlación lineal con las variables de la teca, lo que tiende a hacer inviable su uso como covariables en la modelización geoestadística. Sin embargo, el kriging con deriva externa predice los patrones espaciales de las variables forestales con mayor detalle, lo que da como resultado a posibles errores de suavización menores que los obtenidos por el kriging ordinario, y proporciona recomendaciones más precisas para la gestión localizada en plantaciones de teca. La integración de variables de teledetección en el inventario forestal mediante geoestadística es ventajosa para cartografiar la distribución espacial de las variables de los rodales de teca.

Abstract Detailed knowledge of teak stand structure is necessary for sustainable management plans. The integration of remote sensing variables with geostatistical modeling in teak forest stands has not been sufficiently studied and, therefore, the aim was to model the spatial distribution of teak stand variables, adding covariables. The study was carried out on 19-year-old teak stand in Brazil with 213 hectares in the initial spatial of 3 m x 3 m. Geo-referenced plots of 900 m² were allocated, and forest variables were obtained after thinning. Vegetation indices were calculated from arithmetic operations conducted between the Landsat image bands. The interpolation of forest variables was performed by the geostatistical univariate method of ordinary kriging, as well as by the multivariate method of kriging with external drift, considering the remote sensing variables as covariables. Statistical analysis of remote sensing variables shows a weak linear correlation with teak variables, which tends to make them unviable to use as covariables in geostatistical modeling. However, kriging with external drift predicts spatial patterns of forest variables with greater detail, which results in lower possible smoothing errors than those obtained by ordinary kriging and provides more accurate recommendations for localized management in teak stand. The integration of remote sensing variables in forest inventory through geostatistics is advantageous for mapping the spatial distribution of teak stand variables.

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.

ABSTRACT This study evaluated the postural discomfort and health risks of workers in manual forest plantation operations of a company located in the region of Campos Gerais, Paraná State. Data was collected through interviews, using the postural diagram proposed by Corlett, in a sample of 226 workers from manual planting, fertilization and herbicide application operations. The results indicated that manual planting operations caused greater postural discomfort in the legs of 56% of workers, while the fertilization and herbicide application caused discomfort in the shoulders of 41% and 56% of workers, respectively. The perception of postural discomfort during work is important to assist managers in adopting ergonomic measures for improving the safety and health of workers.

RESUMO A análise espacial da compactação do solo causada pelo sistema de colheita da madeira pode auxiliar no planejamento das operações florestais. Objetivou-se, com este trabalho, identificar e mapear os níveis de compactação do solo, causados pelas máquinas, ao longo das trilhas de extração, pelo sistema de colheita de madeira de árvores inteiras. Foi estudado o sistema de colheita da madeira composto por feller buncher, skidder e harvester, sendo instaladas quatro malhas amostrais nas diferentes distâncias de extração da madeira (0 a 50; 51 a 100; 101 a 150 e 151 a 200 m) e avaliada a compactação do solo em quatro camadas de profundidade (0 a 10; 11 a 20; 21 a 40 e 41 a 60 cm), a fim de verificar o efeito da variação do tráfego do skidder, ao longo do talhão, por estudo das resistências do solo à penetração, com penetrômetro digital. A partir da técnica de geoestatística foram elaborados mapas temáticos e quantificadas as áreas com os diferentes níveis de compactação. Os resultados permitiram localizar as regiões ao longo do talhão com diferentes intensidades de compactação, sendo que a região próxima à margem do talhão apresentou os maiores níveis de compactação, com resistência à penetração acima de 2 Mpa e comprometendo em torno de 20% da área total, na primeira classe de distância. As demais classes de distância de extração não atingiram níveis significativos de compactação, mostrando que o aumento da intensidade de tráfego não influenciou as propriedades físicas do solo. A técnica de geoestatística mostrou-se viável para a determinação da compactação do solo nas diferentes regiões do talhão, podendo favorecer o planejamento das operações de preparo de solo.

ABSTRACT The spatial analysis of soil compaction caused by the wood harvesting system can assist in the planning of forest operations. The aim of this work was to identify and map the levels of soil compaction along the traces of wood extraction caused by the machines in the harvesting full tree system. Was studied the wood harvesting system composed of the feller buncher, skidder and harvester, being sample meshes installed at the different wood extraction distances (0 to 50; 51 to 100; 101 to 150 and 151 to 200 m), and soil compaction was evaluated in four depths (0 to 10; 11 to 20; 21 to 40 and 41 to 60 cm), in order to verify the effect of the variation of the skidder traffic along the field through the penetration resistance of the soil with the use of a digital penetrometer. Through of the geostatistics technique, thematic maps were elaborated and the areas with the different levels of compaction were quantified. The results allowed to locate the regions along the plot with different intensities of compaction, being that the region next the margin of the plot presented greater soil compaction with a resistance to penetration above 2 MPa and compromising approximately 20% of the total area of the first class distance. The other classes of extraction distance did not reach this level of compaction, showing that the increase of traffic intensity wasn’t influenced the soil physical properties. The geostatistical technique proved to be feasible in the determination of soil compaction in the different areas of the field, and may favor the planning of soil preparation operations.

ABSTRACT This study evaluated the effect on Oxisol soil compaction of traffic by wood harvesting machines from different extraction distances carried out by a logging company located in Paraná State. The harvesting system was composed of a feller buncher, skidder and harvester, in which soil compaction was evaluated at four extraction distances and four depths by means of density, porosity and soil penetration resistance. Increased machine traffic resulted in the highest compaction in the soil surface layers on the extraction trail, with the highest intensity in the region near the edge of the stand and with values above the critical density limits. Soil penetration resistance was critical in the row of traffic over the stand with significant effects at a of 0.11 to 0.60 m, which is the recommended depth for soil preparation.

RESUMO Considerando a hipótese de que os volumes de madeira apresentam dependência espacial, cujo conhecimento contribui para o manejo de precisão, o objetivo deste trabalho foi estimar a variabilidade espacial do volume de sortimentos de madeira e identificar seus padrões espaciais em povoamentos de Tectona grandis. Utilizou-se um conjunto de dados de 1.038 árvores para ajustar funções de afilamento e estimar os volumes para fuste total, serraria e lenha em 273 parcelas alocadas em povoamentos de T. grandis ao oitavo ano de idade, o qual representa o segundo desbaste que possibilita volumes comerciais. Modelos de semivariogramas foram aplicados para ajustar a dependência espacial e a krigagem pontual foi utilizada para compor mapas de volume. A modelagem geoestatística permitiu estimar a variabilidade espacial de T. grandis e desenvolver mapas de volume de madeira. Assim, tratamentos silviculturais, como desbaste e poda, bem como planejamento de intervenções espaciais, podem ser recomendados para produtos de madeira almejados.

ABSTRACT Considering the hypothesis that the wood volumes present spatial dependence, whose knowledge contributes for the precision forestry, the aim of this work was to estimate the volume spatial variability for timber assortments and identify their spatial patterns on Tectona grandis stands. A dataset of 1,038 trees was used to fit taper models and estimate the total stem, sawlog, and firewood volumes in 273 plots allocated on T. grandis stands at eight years old, which represents the second thinning that enables commercial volumes. Semivariograms models was applied to fit the spatial dependence, and punctual kriging was used to compose volume maps. Geostatistical modeling allowed us to estimate the T. grandis spatial variability and develop timber volume maps. Thus, silvicultural treatments, such as thinning and pruning, as well as for planning spatial interventions, are possible to be recommended for aimed wood products.

Este trabalho avaliou a compactação do solo submetido ao tráfego do harvester e do forwarder na colheita de madeira em povoamentos de Pinus taeda L. Os dados foram coletados em uma empresa florestal localizada no município de Campo do Tenente, estado do Paraná. A avaliação da compactação foi feita por meio dos parâmetros físicos densidade do solo, porosidade total, porosidade de aeração e resistência do solo à penetração em três níveis de profundidades: 0 a 15 cm, 15 a 30 cm e 30 a 50 cm. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey ao nível de 95% de probabilidade. O tráfego das máquinas provocou uma maior compactação nas camadas superficiais do solo, sendo que após o tráfego do forwarder houve um aumento no incremento da resistência do solo à penetração, em relação à testemunha, da ordem de 151,4%, com valor médio de 1,76 Mpa. Não houve diferença estatística significativa nas propriedades do solo devido ao tráfego das máquinas de colheita no sistema de toras curtas.

This study evaluated the compaction of a soil submitted to the traffic of wood harvesting machines in Pinus taeda L. stands. The data were obtained from a forest company located in the municipality of Campo do Tenente, Parana state, Brazil. Soil compaction was evaluated by determining the following physical parameters: bulk density, particle density, total porosity, aeration porosity, and soil penetration resistance at three depths: 0 to 15, 15 to 30, and 30 to 50 cm. The data were submitted to analysis of variance, and means were compared by the Tukey test at 5% probability level. The results show that the traffic of forest machines caused greater compaction in the soil surface layers after the traffic of forwarders, with an increase of 151.4% in the increment of soil penetration resistance compared with the control, with a mean value of 1.76 MPa. We conclude that there are no statistically significant differences in soil properties due to machine traffic in the cut-to-length system.

Nesta pesquisa, objetivou-se realizar uma avaliação da carga de trabalho físico e biomecânica de trabalhadores nas atividades de roçada manual e semimecanizada para a implantação de plantios florestais. A carga de trabalho físico foi avaliada por meio do levantamento da frequência cardíaca dos trabalhadores nas diversas fases do ciclo de trabalho, com uso de um monitor Polar Oy. A avaliação biomecânica foi realizada por meio de filmagens dos trabalhadores no trabalho, sendo definidas as posturas típicas e os dados analisados no programa 3DSSPP (Programa de Predição de Postura e de Força Estática), desenvolvido pela Universidade de Michigan, EUA. Os resultados mostraram que, a atividade de roçada manual requereu maior esforço físico, com carga cardiovascular acima do limite máximo recomendado de 40%, sendo a atividade classificada como pesada. Nesse método de trabalho, várias articulações dos trabalhadores apresentaram riscos de lesões, sendo o quadril a articulação mais comprometida, com percentual de capazes variando entre 88 e 92%.

The objective of this research was to evaluate of the physical work load and biomechanical of workers at manual and semi-mechanized mowing activities for the planting the forests. The physical work load was evaluated in a survery of the workers cardiac frequency in different stages of the work using a Polar Oy monitor. To the biomechanic evaluation the workers were filmed in the execution of the work, defined the typical postures adopted and the date analyzed in program 3DSSPP (3D Static Strength Prediction Program) developed for University of Michigan, USA. The results showed that the activity of manual mowing required greater physical effort, with cardiac frequency above the maximum limit recommended of 40% and the activity was classified as heavy. In this method of working the various joints of the workers showed injurie risks. The hip joint articulation was the most affected, with capable percentage varying between 88 and 92%.