Canopy seed banks in Mediterranean pines of southeastern Spain: a comparison between Pinus halepensis Mill., P. pinaster Ait., P. nigra Arn. and P. pinea L.

Tapias, R Gil, L Fuentes-Utrilla, P Pardos, JA

R. Tapias et al., Canopy seed banks in Mediterranean pines of southeastern Spain: a comparison between Pinus halepensis Mill., P. pinaster Ait., P. nigra Arn. and P. pinea L., J ECOLOGY, 89(4), 2001, pp. 629-638

45

INGLESE

Article

Environment/Ecology

JOURNAL OF ECOLOGY

0022-0477 → ACNP

89

4

2001

629 - 638

ISI

0022-0477(200108)89:4<629:CSBIMP>2.0.ZU;2-D

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 begin s, 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 se ed bank (3-100 x 10(4) seeds ha(-1)). Fruiting started at 5 years of age. M ore than 86% of the cones were serotinous and had opening temperatures from 49.3 to 51.3 degreesC. 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 se eds ha(-1)) and a lower percentage of serotinous cones (66.7%), with lower cone-opening temperature (45.8 0.8 degreesC) and later first fruiting (12 y ears) than any of our three P halepensis populations. 4 Populations of P. nigra and P. pinea did not show any fire adaptations: f lowering 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 co lonization in species or populations where crown fires are frequent. Late f lowering and non-serotinous cones of P. nigra and P. pinea suggest that the y may have evolved where ignition leads only to low intensity ground fires.