Effects of climate change on the distribution of Pinus sylvestris L. stands in Spain. A phytoclimatic approach to defining management alternatives

This paper presents some contributions on the possible effects of climatic change on the distribution of Pinus sylvestris L. stands in Spain. We studied the phytoclimatic status of Scots pine in current climate conditions (period 1951-1999) and in projected future climate conditions (2050). The phytoclimatic diagnosis followed a modified version of the Allué-Andrade phytoclimatic system. This calculation determines potential areas for Scots pine totalling 8,444,700 ha in current climate conditions and only 1,269,100 ha in 2050 conditions. The shrinkage of the area is especially pronounced in the southern half of Spain, where the model predicts that the species will practically disappear from the Baetic mountain ranges and from a major part of the Central System. In phytoclimatic terms, the maximum values of suitability correspond chiefly to the oroborealoid transitional to nemoral subtype VIII(VI)1 in current conditions, but in projected future conditions the maximum values correspond to areas currently assigned to oroarticoid transitional to oroborealoid subtypes X(VIII). The lowest viability scores are found in the southern half of the Iberian Peninsula and in Mediterranean transitional and nemoromediterranean subtypes. The results also suggest that stands of Pinus sylvestris will migrate upwards and will encounter a serious limitation in the scant availability of high mountain areas other than in the large northern massifs like the Pyrenees and the Cantabrian Cordillera, which accounts for their scant capacity to colonize new areas (2,134 km2 as opposed to extinction over 73,890 km2).