作者单位:Faculty of Agronomy and Agroindustries, National University of Santiago del Estero, Av/Belgrano (S) 1912, 4200 Santiago del Estero, Argentina[1]E.T.S.I Mountains and E.U.I.T Forestry, Polytechnic University of Madrid, Av/Ciudad Universitaria s/n., 28040 Madrid, Spain[2]