Robson José de Oliveira

Avaliação técnica e econômica da extração de madeira de eucalipto com"clambunk skidder"

The objective of this study was to evaluate technical and economic log extraction activities using a clambunk skidder with tracks over the tires. The technical evaluation consisted in determining the log extraction productivity indexes and the economic evaluation was based on operational cost determination. The experimental design was complete randomized, with a 3x2x5 factorial arrangement (three slope levels, two wood productivity classes and five ranks of extraction distance, with three repetitions). In a general way, the results showed that the equipment productivity decreases with the increase of the slope terrain and the extraction distance. Its productivity varied from 18.34 m³.h -1 to 72.08 m³.h-1. The operational cost was US

Análise da trafegabilidade em estradas florestais utilizando métodos computacionais

90.93 per effective worked hour.

Evaluación de los efectos de la rotación en operadores de motosierras

RESUMO – As estradas florestais sao o principal meio de integracao entre as florestas e as empresas. A partir do exposto, percebe-se a necessidade nao apenas da correta aplicacao de atividades de manutencao, mas tambem de se determinar o tempo exato para tal intervencao. Partindo desse pressuposto, este trabalho apresenta os resultados da apreciacao de dois metodos de classificacao da qualidade de estradas nao pavimentadas, com o intuito de se verificar a aplicabilidade dos mesmos na caracterizacao das estradas florestais brasileiras e servir como base para um sistema de gestao das operacoes de manutencao destas vias. Foram medidos os principais defeitos em estradas florestais seguindo um metodo denominado de Indice de Condicao de Rodovia Nao Pavimentada (ICRNP), que serviram de base para gerar um banco de dados para testar a eficiencia do uso de redes neurais artificiais (RNA) na administracao das estradas florestais, minimizando custos e paralisacoes de trafego. Concluiu-se que a utilizacao das redes neurais artificiais apresentou resultados superiores ao metodo do ICRNP.

Perdas de solo e água por erosão hídrica em floresta equiânea em Um Latossolo Vermelho-Amarelo - DOI:10.5039/agraria.v5i4a724

An study was carried out in the natural forests of Pinus caribaea, Pinar del Rio province, Cuba, aiming at the evaluation of the different methods used for clearcuting with chainsaw, using the cut-to-length system conducted in such a way to diminish the risks of the occupational diseases in chainsaw operators, and simultaneously to maintain the productivity levels and work quality. The rotation of the work was tested with an alternation controled method by refueling the chainsaw (MAC), and a free alternation method too (MAL). Both methods used: two chainsaw operators, the lever, and the directional felling in those trees exhibiting more than 40cm diameter. These methods were compared to each other, and to that one traditionally applied on natural forests (T), that consists of one operator and its assistant who besides maintaining their functions during this activity, do not use the lever nor make the directional felling, but rather adopt spontaneous pauses. According to the results, the MAC shows to be more appropriate because: it allows to reduce the risks of accidents and occupational diseases in chainsaw operators; provides the balance of the work physiologic load and the decreases of 13.69% in load and 52.08% in the noxious effects from chainsaw, although the productivity over the effective time showed an increase of 27.32% relative to method (T), so diminishing the operating costs that justify the basic wages corresponding to the operators level for both integrants of the team.

Custos em quatro subsistemas de colheita florestal

Water erosion contributes significantly in soil degradation, and vegetation cover is one of the important factors that influence the intensity of this erosion on the soil. To this end, this study aimed to evaluate soil and water losses by water erosion under natural rainfall in eucalyptus even-aged forest, relating them to limit-values of tolerance in a Red-Yellow Dystrophic Latosol. A standard plot was installed within the forest. From this collection, soil and water collections were carried out, after each erosive rainfall. The estimated soil loss presented and average value of 0.2566 t ha -1 in the study period (six months). The estimated water loss was of 8.36 mm in the study period. These low values found show the sustainability of the studied forest, within the context of erosion, when compared to the soil loss tolerance limit, and to other research findings in native forest and bare soil.

Perdas de solo e água por erosão hídrica em floresta equiânea em um Latossolo Vermelho-Amarelo

O objetivo deste trabalho foi realizar um levantamento e fazer uma analise comparativa dos principais custos operacionais das maquinas florestais: forwarder, harvester e slignshot em quatro subsistemas de colheita em florestas de eucalipto. A analise comparativa englobou um estudo dos custos operacionais dentro de cada subsistema sendo eles divididos da seguinte forma: Subsistema 1: Harvester (Partek 911 + Cabecote 965 BR) e Forwarder (Partek 890 6X6 (18 t)).Subsistema 2: Harvester (Caterpillar 320 BL + Cabecote 965 BR) e Forwarder (Partek 890 6X6 (18 t)).Subsistema 3: Slingshot (Timberjack 608 B HD + Cabecote RISLEY) e Forwarder (Partek 890 6X6 (18 t)).Subsistema 4: Slingshot (Caterpillar 320 BL + Cabecote RISLEY) e Forwarder (Partek 890 6X6 (18 t)).O subsistema 4 Slingshot (Caterpillar 320 BL + Cabecote RISLEY) + Forwarder (Partek 890 6X6 (18 t)) apresentou um menor custo operacional em relacao aos outros subsistemas, correspondendo a uma reducao de ate 15,58% no custo operacional total. Os subsistemas que utilizaram o Havester apresentaram menor consumo de combustivel.