Regeneration in a mixed stand of native Pinus canariensis and introduced Pinus pinea species

Abstract

The main objective of our study is to determine whether regeneration ofPinus pinea(an exotic species) is spreading within aPinuscanariensis(native species) stand. The study area is located in the Natural Park of Tamadaba, 1400 m asl., in the NW of Gran Canaria Island(Canary Islands). Stems and regeneration ofP. canariensisandP. pineawere mapped in five randomly selected plots where both species wereplanted together around 45 years ago. Densities and basal areas of both species were also recorded.P. canariensisdemonstrated a greaterability to disperse thanP. pinea. The two species showed different spatial patterns, withP. pineatending toward a more aggregate spatialdistribution of individuals thanP. canariensis. Bivariate spatial relationships showed no difference from a random spatial distribution, indi-cating the lack of any pattern of aggregation or rejection between the species. These results indicated thatP. pineahas not spread because it isless able to disperse (strongly barochorus) thanP. canariensis(barochorus and anemochorus). Given that the future ability ofP. pineatodisperse cannot be predicted, eradication of this species, together with additional plantings ofP. canariensisin open areas, is proposed torestore theP. canariensisstand.