Performance of Maritime Pine Spanish Mediterranean Provenances at Young Ages in a Transitional Region Between Atlantic and Mediterranean Climates in NW Spain

Maritime pine (Pinus pinaster Ait.) occurs naturally in a wide variety of sites around SW Europe, from typical Mediterranean climates to areas in Northern Spain and France with a strong oceanic influence. Within its distribution range populations are strongly differentiated, showing local adaptations to environmental conditions that have been widely documented in different provenance trials both in the Atlantic region and in the Mediterranean area. In the present paper, we analyzed the performance of six Mediterranean provenances in three sites in the interior of Galicia (NW Spain), a transitional region between Atlantic and Mediterranean climates where few catalogued materials are available for reforestation. Seven year after planting, provenances coming from the mildest climates grew faster but showed inferior stem form. The provenance x site interaction was weak, although some significant provenance rank changes were observed in the driest site. Among the tested provenances, Serranía de Cuenca showed good early growth in all sites and acceptable stem form, being thus a potential recommended material for using in the area. The Albarracín origin showed also good results, with excellent stem form and acceptable growth, especially in the driest site. A combined spatial analysis allowed us to compare the tested provenances with improved materials from Coastal Galicia (NW Spain) and Western Australia planted in adjacent progeny trials. Although the differences were small, the Atlantic material of both breeding programs performed slightly better than the Mediterranean provenances, and represents another alternative material for use in reforestation in this transitional climate region.