Direct sowing of holm oak acorns: effects of acorn size and soil treatment Francisco Bruno Navarro, María Noelia Jiménez, María Ángeles Ripoll, Emilia Fernández-Ondoño, Eduardo Gallego and Estanislao De SimónAnn. For. Sci., 63 8 (2006) 961-967DOI: https://doi.org/10.1051/forest:2006079