Carlos Roberto Sette Junior

Eficiência e desempenho operacional de máquinas Harvester e Forwarder na colheita florestal

The knowledge on productive capacity and variable elements that affect machines efficiency is essential for optimizing operations in forest harvesting. This study aimed to evaluate Harvester and Forwarder machines efficiency and operational performance, for forest exploitation, in the south of the Bahia State, Brazil. Data concerning the number of programmed and effective working hours, as well as reasons for machine downtime, were collected from historical archives, from October 2010 to September 2011. Based on these data, the total working hours, operational efficiency, and mechanical availability were calculated. Harvester machines showed an average of total working hours of 480 hours and 18 minutes, being 75.6% (363.2 hours) of effective work and 24.4% (117.1 hours) of downtime. Forwarder machines showed an average of total working hours of 481 hours and 36 minutes, being 84.7% (407.9 hours) of effective work and 15.3% (73.7 hours) of downtime. The average operational efficiency was of 73.2%, for the Harvester, and 82.2%, for the Forwarder, and technical downtimes, such as displacements and corrective and preventive maintenances, comprised the main reason for explaining those values. The machines operational performance showed to be adequate , according to time distribution, with 76 % and 85 % of effective working time, respectively for the Harvester and Forwarder , and an average of 89 % for mechanical availability , for both machines, which showed satisfactory operational efficiency (above 70%).

SAZONALIDADE DO INCREMENTO EM DIÂMETRO DO TRONCO DE ÁRVORES DE Eucalyptus grandis PELO USO DE DENDRÔMETROS

O presente trabalho teve como objetivo avaliar a sazonalidade do incremento em diâmetro do tronco de arvores de Eucalyptus grandis e sua relacao com as variaveis climaticas e de fertilizacao nitrogenada e com lodo de esgoto. As arvores foram plantadas no espacamento de 3 x 2 m e fertilizadas com nitrogenio (plantio, 6, 12, 18 meses) e lodo de esgoto (plantio e 8 meses), sendo selecionadas 20 arvores de eucalipto por tratamento, de acordo com a distribuicao de area basal do povoamento, instalados dendrometros de aco no DAP e mensurado o incremento em diâmetro de fevereiro/2006 a fevereiro/2008. Os resultados permitem concluir que houve efeito das variaveis climaticas na sazonalidade do incremento em diâmetro do tronco das arvores de eucalipto, sendo observado um periodo de defasagem (lag) de 28 dias para a resposta das arvores em relacao as variaveis climaticas. Com relacao ao efeito da fertilizacao, determinou-se que o incremento em diâmetro do tronco foi maior nas arvores de eucalipto com tratamento de lodo de esgoto em relacao a adubacao mineral com nitrogenio.

EFEITO DA APLICAÇÃO DO POTÁSSIO, DO SÓDIO E DA DISPONIBILIDADE HÍDRICA NA DENSIDADE APARENTE A 12% DE UMIDADE DO LENHO JUVENIL DE ÁRVORES DE Eucalyptus grandis

Expressive area of forest plantations fast-growing of eucalyptus in Brazil and in other regions of the world is under the influence of climate change, water stress and low soil fertility, affecting the growth and the quality of the wood from the trees. This study aimed to evaluate the apparent density at 12% relative humidity of the wood of Eucalyptus grandis trees with 12, 24 and 36 months, with reduced rainfall and nutrition K and Na. The treatments were defined by two water regimes (100% and 66% of rainfall, with artificial reduction with polyethylene sheeting) and three types of nutrition: K (K - 4.5 kmol/ha), N (Na - 4.5 kmol/ha) and control. The apparent density of the samples of diameter at breast height was determined by densitometry profile from digital images of rays X. The results indicated a significant difference in nutrition treatments and water availability in relation to the density of the wood. The radial apparent density profiles showed higher differences in the wood from the third year of evaluation. Digital images of the wood obtained by X-rays allowed to analyze the variation of the apparent density of the wood. Work results may be used as subsidies for the adoption of silvicultural practices in forest plantations in areas with water stress and/or affected by climate change as well as the partial replacement of K by Na.

A PROPOSED METHODOLOGY FOR THE CORRECTION OF THE LEAF AREA INDEX MEASURED WITH A CEPTOMETER FOR PINUS AND EUCALYPTUS FORESTS

Leaf area index (LAI) is an important parameter controlling many biological and physiological processes associated with vegetation on the Earths surface, such as photosynthesis, respiration, transpiration, carbon and nutrient cycle and rainfall interception. LAI can be measured indirectly by sunfleck ceptometers in an easy and non-destructive way but this practical methodology tends to underestimated when measured by these instruments. Trying to correct this underestimation, some previous studies heave proposed the multiplication of the observed LAI value by a constant correction factor. The assumption of this work is LAI obtained from the allometric equations are not so problematic and can be used as a reference LAI to develop a new methodology to correct the ceptometer one. This new methodology indicates that the bias (the difference between the ceptometer and the reference LAI) is estimated as a function of the basal area per unit ground area and that bias is summed to the measured value. This study has proved that while the measured Pinus LAI needs a correction, there is no need for that correction for the Eucalyptus LAI. However, even for this last specie the proposed methodology gives closer estimations to the real LAI values.

Propriedades físico-mecânicas do lenho deteriorado por fungos apodrecedores de árvores de Tipuana tipu

The tipuana was widely used in urban arborization. In general, inadequate management exposes the wood to the action of wood decaying fungi and insects, often associated with the fall of the trees. The aim of this study was to evaluate the physical and mechanical properties of sound and rotten tipuana wood from Sao Paulo Citys afforestation. Thirteen old trees with symptoms of wood deterioration were removed. From the basal region of the trunk were cut 1 m-length stem segments, to characterize the physical and mechanical properties of sound and decayed wood. The results indicated that through the radial wood density profile by X-ray densitometry were classified seven pattern of wood biodeterioration, named (EXS) with accumulation of extractives and sound, (ZR) with the reaction zone and sound, (NS) normal and sound, (PB INC ; PB INT ) incipient and intense white rot (PM INC ; PM INT ) incipient and intense soft rot, with apparent densities of 0.94, 0.92, 0.82, 0.66, 0.41, 0.67 and 0.44 g.cm -3 , respectively. The mechanical tests showed that wood classified as (ZR) (EXS) presented the highest values of strength and stiffness of 84 and 80 MPa and 6461 MPa and 5826, respectively; the (NS) showed values of 62 and 4642 MPa, and the (PB INC ) (PM INT ) the significant and lowest values of strength and stiffness, enhancing (PB INT ) with values of 5 and 571 MPa. The reduction of density, strength and stiffness of wood is related to the biodeterioration of wood cell walls of trees tipuana by decaying fungi

Characteristics of Wood and Charcoal from Eucalyptus clones

The characteristics of wood and charcoal depend on the genetic material and the sampling position on the tree trunk. The objective of this study was to evaluate the effect of clone and longitudinal position on the characteristics of wood and charcoal of Eucalyptus grandis x Eucalyptus urophylla. Specimens belonging to I144 and GG100 clones both at seven years of age were felled and mechanically processed for disc removal at different longitudinal positions of 0, 3, 6, 9, 12 and 15 meters from the ground. The wood and charcoal physical and energetic characteristics were evaluated according to the different longitudinal positions. The genetic material and longitudinal position influenced the wood and charcoal characteristics. Sampling positions on the tree trunks can be considered for the energetic direction of “in natura” or carbonized biomass.

Potencial de espécies de Bambu como fonte energética

The objective of this research work was to evaluate the characteristics of biomass and charcoal of Bambusa tuldoides, Bambusa vulgaris var. vittata and Dendrocalamus asper in order to investigate its potential for energy use. For comparative purposes, we used trees of Eucalyptus grandis x Eucalyptus urophylla hybrids trees with 6 years were employed. The biomass was characterized (specific gravity, proximate analysis, high heating value and energy density). The charcoal was produced with a heating rate of 1,67 oC.min-1 and final temperature of 450°C for later characterization (specific gravity, proximate analysis, high heating value, energy density and gravimetric yield). The bamboo species showed similar or superior energy characteristics in relation to the eucalyptus hybrid, except for the volatiles and ash content. The bamboo species has energy properties that indicate their potential for use as energy source.