CONTENTS

Articles WILVER CONTRERAS, MARY E. OWEN DE CONTRERAS, DARIO GARAY and YOSTON CONTRERAS Manufacturing of particle boards from Caña Brava (Gynerium sagittatum) particles and urea-formaldehyde adhesive WILLIAMS LEÓN and NARCISANA DE PERNÍA Disjunctive ray parenchyma and phyllogeny FIDEL HERNÁNDEZ, MIGUEL PLONCZAK and ALEIDI SANGRONIS Methodological approach to the determination of the option value of the Imataca Forest Reserve MAURICIO JEREZ, LAWRENCE VINCENT and ANA Y. MORET A competition model for teak plantations in the Experimental unit of the Caparo Forest Reserve (Barinas-Venezuela) CLIFFORD PEÑA, BRUNO AÑEZ and MARIO DÁVILA Response of onion (Allium cepa L.) to fertilizers application of sulphur, magnesium, zinc and boron in an alkaline soils ROSAIMA GARCÍA, ALBA GARCÍA and LUISA DELGADO Bacterial wilt the tomato caused by the Biovar 2A, the Ralstonia solanacearum in several localities of the Mérida state, Venezuela JOSÉ G. MENDOZA and EDGAR JAIMES Edafogeomorphological homoneity of an study area located in Quebrada de Ramos river basin, Trujillo state, Venezuela ELVECIO PERNÍA Space sensors for environmental studies, at the doors of the XXI century

Notes LUIS CEDEÑO and CHRYSTIAN CARRERO First report of Erysiphe cichoracearum on potato in Mérida-Venezuela OSVALDO ENCINAS Forest certification or green stamp

Thesis GUSTAVO RAMÍREZ Development and application of a computarizer system to monitoring and evaluation success in Mucujún river watershed VICENTE GARAY Variation in plantations of Eucaliptus spp. in Sanare, state of Lara-Venezuela, with , management purposes JULIAN GUTIÉRREZ Use of digital image processing and geographic information systems techniques in determination of vegetation cover and use changes, Mucujun river basin, Mérida state BOLÍVAR GAMBOA Preparation and characterization of active charcoal through caribe pine and teak branch