Amaury Paulo de Souza

The forestry sector has experienced continuous growth in investments and technological innovations, particularly in harvesting operations, which have been significantly enhanced by these advancements. In this context, the systematic monitoring of operator performance is an essential tool for assessing individual progress over time, based on the experience acquired in machine operation. This approach enables managers to track learning curves, plan targeted training actions, and promote the continuous improvement of operational efficiency. The objective of this study was to evaluate the productivity evolution of Harvester and Forwarder operators as a function of field experience in a forestry company in the southwestern region of the Maranhão state, Brazil. The average time consumption for performing operational cycles and their elements was assessed, correlating the time spent with experience duration and the average individual volumes of the harvested areas. A time and motion study was used to evaluate operators without prior experience. The time consumed in each element of the operational cycle and the effective working time for cutting and extraction operations were determined. In the Harvester cycle, the “Processing” element accounted for the highest percentage of time consumption, whereas in the Forwarder cycle, the “Loading” stage was the most time-consuming, regardless of the operators’ level of experience. Correlation analysis showed that, for the Harvester, the average individual volumes of the harvested areas had a greater influence on the evolution of cycle time consumption than operator experience. Conversely, for the Forwarder, field experience showed a more significant correlation. The practical experience of operators showed a significant impact on productivity, with percentage gains of 71.0% for the Harvester and 84.6% for the Forwarder. These results demonstrate that the accumulation of operational experience is directly related to performance improvement, highlighting the importance of continuous monitoring of operator performance over time.

RESUMO Pressões e cobranças na colheita florestal podem comprometer a saúde, o bem-estar e a qualidade de vida dos trabalhadores. A análise do perfil e nível de satisfação dos operadores permite melhorar a qualidade de vida no ambiente de trabalho. O objetivo foi avaliar o perfil individual (idade, dependentes, origem, endereço, qualificação profissional, experiência no setor florestal, Índice de Massa Corporal (IMC) e a percepção individual (condições de trabalho, treinamento inicial, fatores do ambiente e as condições de stress ou cansaço) de operadores de máquinas de colheita florestal de alto desempenho. Os dados foram obtidos por aplicação de questionário aos operadores de máquinas Harvester e Forwarder em empresa florestal no sudoeste do Estado do Maranhão, Brasil. Operadores, dessas máquinas, eram, em geral, jovens, sendo 94% homens com idade média de 26,5 anos, com um ou mais dependentes e origem, principalmente, urbana. Nenhum operador apresentou IMC de obeso, 63,79%, peso adequado e 34,48%, sobrepeso. Um percentual de 84,62% completaram o ensino médio, mas sem experiência no setor florestal e 18,75% relataram terem trabalhado em outra empresa florestal. Mais de 80% dos operadores avaliaram como bons os fatores e condições de trabalho, sem considerá-lo estressante ou cansativo. Porém, um total de 85,48% estavam insatisfeitos com o regime de folgas e 60% julgaram insuficiente o número de dias de descanso. O treinamento inicial foi considerado bom e a maioria afirma que gostaria de reciclagens anuais.

The introduction of the forwarder for wood extraction has provided significant improvements in forest harvesting operations. However, these machines have a high energy demand due to the high engine speed and hydraulic system pressure. Such circumstances increase the operational cost and the emission of polluting gases. Therefore, the objective of this research was to quantify technical, economic, and environmental forwarder parameters as a function of hydraulic pump pressure and engine speed. The research was carried out in the northeastern part of Brazil. The machine operations were analyzed in forest stands with average individual volumes of 0.10 and 0.29 m³ trees⁻¹. During the experiment, the machine was configured to operate with pump pressures of 240, 235, and 230 bar and engine speeds of 1550, 1475, and 1400 rpm, totaling 9 combinations. The technical analysis included the study of times and movements, productivity, and fuel consumption per cubic meter. Regarding the economic parameters, the production costs of the machine were determined. Environmental impact was measured by determining the amount of carbon dioxide and methane emitted. The results were analyzed by regression analysis. For the volume of 0.10 m³ tree⁻¹, the combination of pump pressure of 230 bar and engine speed of 1400 rpm showed the best results. For the volume of 0.29 m³ tree⁻¹, the combination of pump flow of 240 bar and engine speed of 1550 rpm provided the best results.

Excavators-based harvesters are self-propelled forestry tractors that normally operate at maximum engine speed. This results in maximum hydraulic pump flow regardless of operating conditions. The objective of this work was to quantitatively investigate the technical performance, as well was the economic and environmental outcomes, of excavators-based harvester as a function of engine speed and hydraulic pump flow. Machine operations were analyzed in forest stands with an individual average volume of 0.08 or 0.16 m3 tree–1. The machine was operated with engine speeds of 2060, 2000, 1950, or 1900 rpm and hydraulic pump flow rates of 300, 295, or 290 L min–1. This resulted in 12 different excavator-based harvester configurations. With regards to the technical performance of the machine, a study of times and movements, productivity, hourly fuel consumption, and fuel consumption was performed. Economic outcomes were considered in terms of the operational costs, while environmental impact was determined by carbon dioxide and methane emissions. Optimal excavator-based harvester operating conditions with an average volume of 0.08 m3 tree–1 were determined to be with an engine speed of 2000 rpm and a hydraulic pump flow rate of 295 L min–1. With the 0.16 m3 tree–1 volume, the best results were obtained with an engine speed of 2000 rpm and a hydraulic pump flow of 300 L min–1.

Reducing engine speed and pressure of forest machine hydraulic pumps may be a strategy to achieve a reduction in fuel costs. However, this approach can positively or negatively affect the ergonomic parameters of the operators, in particular, the whole-body vibration and repetitive movements of the operators. The objective of this research was to evaluate the acceleration force resulting from normalized exposure (Aren) and the Real Occupancy Rate and Maximum Occupancy Rate considering Repetitive Activities (ROR-MORCRA) of forwarder operating at different pump pressures, engine speed, and volume of trees. The research was carried out in forest stands with an individual average volume of 0.10, 0.14, and 0.29 m³ tree-1. For each volume, the machine was configured to operate at hydraulic pump pressures of 240, 235, and 230 bar and engine speed of 1550, 1475, and 1400 rpm, totaling 9 combinations. The values were measured in the 9 combinations and also in each phase of the machine operational cycle, using a triaxial accelerometer of the 01dB brand, model Vib 008. To determine ROR, percentage of rest due to regular breaks, percentage of time with low demand activities, percentage of usual irregular breaks, and percentage of very short breaks were calculated. To estimate MORCRA, the repetition, strength, and static effort factors were calculated. In volumes of 0.10, 0.14, and 0.29 m³ tree-1, the highest Aren values were 0.82, 0.88, and 0.99 m s-2, respectively, being obtained at the 1550 rpm engine speed. The forwarder logging operation is characterized as an ergonomic risk, which can cause discomfort, fatigue, and injuries to operators.

Níveis de ruídos em diferentes postos de trabalho em uma colhedora de tomate industrial / Noise levels in different jobs in an industrial tomato havester

Variabilidade espacial de clones de Eucalipto em função do preparo de solo e adubações / Spatial variability of Eucalyptus clones in the function of soil tillage and fertilization

Na atividade de colheita florestal, independentemente do grau de mecanização, o trabalho humano estará sempre presente, o que exige o planejamento adequado para diminuir os índices de acidentes e de doenças ocupacionais que se acumularam no Brasil. No período de 2007 a 2016, ocorreu o total de 18.934 registros em atividades de floresta plantada no país. Apesar da variedade de técnicas de avaliação de risco disponíveis na literatura, o setor florestal, em especial a colheita florestal, carece do processo próprio que possa realizar esse planejamento e que seja de fácil compreensão e aplicação. Dessa forma, objetivou-se com esta pesquisa estabelecer a matriz como ferramenta de apoio para avaliação do nível de risco, que inclui a análise da frequência da atividade, probabilidade do evento de risco e gravidade da lesão, conforme parâmetros nacionais já observados. A construção da matriz utilizou como métodos estudo de pesquisadores brasileiros e norma britânica de gestão de segurança e saúde no trabalho. Como resultado, obteve-se uma matriz com quatro classificações de risco: baixo, moderado, alto e crítico, distribuídos em pontuações que variam de 1 a 36, de forma a estabelecer um processo de avaliação de risco que considere frequência da atividade e probabilidade e gravidade do acidente.

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.

O objetivo deste trabalho foi avaliar os riscos ergonômicos a que os trabalhadores estavam expostos durante o desenvolvimento das atividades florestais de roçada e desgalhamento semimecanizado. Foi avaliada, para cada uma das atividades desenvolvidas, a exposição ao ruído e vibração, a carga de trabalho físico e a biomecânica. Os resultados demonstraram que as atividades florestais avaliadas oferecem diferentes riscos ergonômicos aos trabalhadores. Os níveis de ruído e vibração das roçadeiras e motopodas avaliadas proporcionaram valores acima do limite de tolerância recomendado pela norma brasileira. Na avaliação da carga de trabalho físico, em ambas as atividades avaliadas, a carga cardiovascular foi acima do valor recomendado. Na análise biomecânica, foi verificado que o dorso, coxofemoral, tornozelo e cotovelo são articulações que exibiram alto risco de lesões.