Canopy Seed Banks in Mediterranean Pines of South-Eastern Spain: A Comparison between Pinus halepensis Mill., P. pinaster Ait., P. nigra Arn. and P. pinea L

• Published in: The Journal of ecology Vol. 89; no. 4; pp. 629 - 638
• Main Authors: Tapias, Raúl, Gil, Luis, Fuentes-Utrilla, Pablo, Pardos, José A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK British Ecological Society 01.08.2001; Blackwell Science Ltd
• Subjects: canopy seed bank; cone‐opening temperature; Coniferous forests; early flowering; Ecosystems; fire; Fire ecology; Forest canopy; Forest ecology; Forest fires; Human ecology; Population ecology; Seed banks; serotinous cones; Tree age
• ISSN: 0022-0477; 1365-2745
• DOI: 10.1046/j.1365-2745.2001.00575.x

1 Canopy seed banks were analysed in post-fire stands of Pinus halepensis, P. pinaster, P. nigra, and P. pinea. We determined age when flowering begins, age of first cone bearing, presence of serotinous cones and cone-opening temperatures. 2 By 15 years after the fire, P. halepensis had developed a large canopy seed bank (3-100 x 104 seeds ha-1). Fruiting started at 5 years of age. More than 86% of the cones were serotinous and had opening temperatures from 49.3 to 51.3 °C. Cones from adult trees opened at lower temperatures than those from young trees. 3 A 16-year-old P. pinaster stand had a smaller seed bank (12 000 viable seeds ha-1) and a lower percentage of serotinous cones (66.7%), with lower cone-opening temperature (45.8 ± 0.8 °C) and later first fruiting (12 years) than any of our three P. halepensis populations. 4 Populations of P. nigra and P. pinea did not show any fire adaptations: flowering was insignificant even 15 years after fire, and none of the cones produced were serotinous. 5 Serotinous cones represent a fire-survival strategy for P. halepensis and P. pinaster. Early flowering is also necessary for successful post-fire colonization in species or populations where crown fires are frequent. Late flowering and non-serotinous cones of P. nigra and P. pinea suggest that they may have evolved where ignition leads only to low intensity ground fires.