Resumo-Na busca pelo aproveitamento dos resíduos gerados desde a produção florestal até os processos de transformação industrial da biomassa, desenvolveu-se o processo de briquetagem. A aglomeração de partículas de madeira facilita as operações de manuseio do material combustível, além de concentrar a energia disponível em termos de volume. O objetivo do presente trabalho foi avaliar se a matéria-prima tem influência na qualidade do briquete e verificar o efeito da pressão aplicada durante o processo nas características energéticas e mecânicas do produto final, além de avaliar o comportamento da mistura de materiais (MIX) em relação aos materiais puros. Os briquetes foram produzidos em uma briquetadeira piloto, tipo pistão hidráulico, a 120 ºC com pressão constante de 50 bar por oito minutos e 65, 95 ou 130 bar por dois minutos. Foram utilizados seis briquetes para cada tratamento. As características avaliadas foram poder calorífico superior (PCS), densidade aparente e resistência à compressão. A matéria-prima tem maior influência na qualidade dos briquetes do que a pressão de compactação. A baixa pressão é a mais indicada para briquetes de biomassa florestal de Pinus sp. Nesta, o MIX apresentou qualidade satisfatória de briquetes com PCS de 4.773 kcal kg-1 , densidade aparente de 1.220 kg m-³ e resistência à compressão de 167 kgf cm-2. Termos para indexação: Pinus sp; poder calorífico superior; densidade aparente; resistência à compressão. Variables of briquetting process and quality of forestry biomass briquettes Abstract-In the quest for recovery of waste generated from forest production to the process of industrial transformation of the biomass it was developed the process of briquetting. The cluster of wood particles facilitates the operations of handling of combustible material in addition to concentrating the available energy in terms of volume. The purpose of this study was to evaluate whether the raw material affects the quality of the briquette and verify the effect of pressure applied during the mechanical and energy characteristics of the final product, and to evaluate the behavior of the material mix (MIX) compared to pure materials. The briquettes were produced in a pilot briquetter, hydraulic piston, 120 °C with a constant pressure of 50 bar for eight minutes and 65, 95 or 130 bar for two minutes. Six briquettes were used for each treatment. The characteristics evaluated were calorific value (GCV), bulk density and compressive strength. The raw material has a greater influence on the quality of briquettes than the compaction pressure. The low pressure is the most suitable for Pinus sp forest biomass briquettes. In this, MIX submitted satisfactory quality of briquettes with PCS 4,773 kcal kg-1 , density 1220 kg m-³ and compressive strength of 167 kgf cm-2 .

For the purpose of reforestation and wood supply the leguminous tree Anadenanthera peregrina, a native species, was intercropped with Eucalyptus camaldulensis in a degraded semiarid area of Brazil. Single and mixed stands of these species were inoculated with Rhizobium and/or arbuscular mycorrhizal fungi (AMF). The growth of all species in mixed stands did not differ from those cultivated in monoculture and land equivalent ratio (LER) exceeded unity in intercropped plots. Inoculated plants showed greater height and diameter growth and dry matter and nutrient concentration in plants of A. peregrina was higher in inoculated single plots. The distribution, composition and density of AMF species was related to the rhizosphere effect of plant species. The intercropped model where all the plants were inoculated achieved soil AMF diversity patterns similar to those of the preserved area and showed also higher soil organic matter, nutrient content as well as a reduction in soil macroporosity. This model of intercropping may be considered as an efficient system for reforestation under semiarid conditions.

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This paper discusses the relationship between nutrients concentration in the leaves and soil, as well as tree growth in Eucalyptus grandis plantations. The survey was carried out in five locations in the Cerrado region of the State of São Paulo, Brazil. It was concluded that the trees were adequately nourished with S, Fe, Mn and Zn; P concentrations in the leaves were below the optimum reported in literature; K and Mg were the nutrients that most seriously limited tree growth, in ali locations despite fertilization; concentrations of 2.6 and 7.5 mg/g D.M. of Mg and K were adequate leveIs for both nutrients; fertilization with N, P, K and Mg can increase the growth of the trees in alllocations; Ca and B concentrations in the leaves were not related to the growth of the trees, showing a dilution effect. RESUMENEste trabajo fue desarrollado con el objetivo de identificar los elementos minerales limitantes aI crecimiento de Eucalyptus grandis plantado en distintos sitios. Para su ejecución fueron colectadas muestras de tejido vegetal y suelo, en plantaciones con 3 afios de edad, en 5 sitios deI Estado de São Paulo, Brasil. Los resultados obtenidos permitieron las siguientes conclusiones: las plantaciones de Eucalyptus en las regiones estudiadas se encuentran adecuadamente suplidas de S, Fe, Mn y Zn; los contenidos de P en las hojas se encuentran bajo el valor óptimo reportado en la bibliografía; K y Mg son los nutrientes minerales que limitan más significativamente el crecimiento de los árboles en todos los sitios, también en plantaciones fertilizadas; árboles cuyas hojas presentan contenidos de 2.6 y 7.5 mg/g en la materia seca de Mg y K, respectivamente, están adecuadamente nutridos de estos elementos; el aumento en la oferta de N, P, K Y Mg en el suelo, a través de una fertilización, puede aumentar el crecimiento de los árboles en todos los sitios; los contenidos de Ca y B en las hojas no están relacionados con el crecimiento de los árboles, mostrando incluso efecto de dilución.

Incident precipitation, throughfall and stemflow under a Eucalyptus grandis stand were collected and their chemical composition was analysed to quantify nutrient accretion to the soi! by precipitation during a 12 month period from November 1992 through October 1993. The stand was stablished in the State of São Paulo, Brazil, in 1991 after applications of pulp residues and ash. Throughfall and stemflow were generally richer in K, Ca, Mg and S04 but very poor in P and N probably due to the direct absorption of the latter by the canopy. The same was observed with K but only in the plot that received no pulp residue or ash. This paper summarizes the results of the present nutrient input study, correlating it with the nutrient requirement of E. grandis. RESUMEN Este trabajo evalúa la contribución de las lluvias en nutrientes minerales en el período de noviembre de 1992 hasta octubre de 1993, en plantaciones de Eucalyptus grandis abonadas con fertilizantes minerales y con residuos de celulosa y de ceniza de cal dera en el Estado de São Paulo, Brasil. Para la captación deI agua de precipitación, fueron instalados colectores en área abierta, sin Eucalyptus, y para la evaluación de la precipitación efectiva, debajo de las copas de los árboles. Se observó que después de la circulación por la copa y tronco de los árboles, el agua de lluvia presentó mayores cantidades de potasio, calcio, magnesio y sulfato. Por otra parte, nitrógeno y fósforo presentaron, por regIa general, menores cantidades, indicando una posible absorción, principalmente deI nitrógeno, directamente en el doseI arbóreo. Para el potasio hay una disminución en su cantidad en el agua de lluvia, después que ésta atraviesa la cubierta forestal, en el tratamiento que recibió menor cantidad de nutrientes en la fertilización.