Gradient analysis of exotic Pinus radiata plantations and potential restoration of natural vegetation in Tenerife, Canary Islands (Spain)

Afforestation on the island of Tenerife has been carried out mainly with the native species of pine Pinus canariensis Chr. Sm. Ex DC. However, the exotic pine Pinus radiata D. Don has been introduced in some areas. Several studies have shown that plantations of exotic species facilitate forest succession in their understories on sites where disturbances prevent the recolonization by native forest species. We randomly located 250 plots in stands of P. radiata, on the island of Tenerife and recorded species. Abiotic characteristics of the plots were also noted. We evaluated the regeneration of potential vegetation of the laurel forest and pine forest under a canopy of an exotic pine species. Analysis of the species composition, resulted in four well defined groups: advanced laurel forest group (ALF), undeveloped laurel forest group (ULF), ruderal group (RU) and Canarian pine stand group (CPS). These groups can also be discriminated base on altitude, slope or canopy cover. For ALF and ULF we propose thinning restoration management and the planting of new individuals of laurel forest species. For RU and CPS, because they are potentially P. canariensis stands, we propose continuous elimination of P. radiata and enrichment with new individuals of P. canariensis.