Eucalyptus in Gran Canaria, identification and chorology. Towards a historical review.
This taxonomic study of Eucalyptus species on the island of Gran Canaria inventories and samples 30 taxa belonging to two genera (26 of Eucalyptus and 4 of Corymbia), plus three other unidentified taxa, and a further taxon that had been sampled by Kunkel, but was not found in the field trips carried out. The history of the arrival of these species comprises 4 main stages: the influence of the hygienist medicine in the late XIX century; the influence of the so-called "Apostle of the tree" Francisco Gonzalez Diaz, great defender of the tree, early on the XX century; the development of the "National Plan for the repopulation of forests" in 1940; and finally, the demand generated by the building sector in the decade of the 60s (XX century). The cultivation and settlement of these species are closely connected to these historical processes, and 6 main events can be distinguished: Introductions along the roads, introductions of shrubby species of the E. lehmannii group, planting of specimens related to the first group in small patches or little forests in slopes, planting for wood exploitation, and finally planting in arboreta. We note the naturalization of at least 14 species: Eucalyptus camaldulensis, E. globulus, E. talyuberlup, E. blakelyi, E. conferruminata subsp. recherche, E. cornuta, E. dwyeri, E. gonphocephala, E. lehmannii, E. moluccana, E. ovata, E. robusta, Corymbia citriodora and C. variegata. However, in none of these cases have we observed an invasive behaviour, as the naturalization is, in general, limited. Therefore, the maintenance and conservation of some eucalypts and eucalypt groups is justified by historical, cultural and biodiversity reasons.