Desarrollo de vegetación y radiación solar que incide en laderas de la sierra de Béjar, Salamanca (España)

Abstract

A detailed study was carried out about the vegetation and solar radiation on hillside grounds of the Sierra de Bejar according to its characteristic orientation and slope for a better exploitation of its ecological resources. Chorologically the area is located in carpetano-iberico-leonesa province, bejarano-gredense section, bejarano-tormantino subsector. Its topography presents great contrasts, alternating great ondulations with high slopes. For as, in this area there was a three bioclimatic grounds: supramediterranean, oromediterranean and crioromediterranean. At heights from 1500 m onwards, the lowest values for average radiation in slopes oriented N, NE, NEN, NON, and NO have been estimated (186.9 cal.cm -2 .year -1 in winter, 246.8 cal.cm -2 .year -1 in autumn, 486.5 cal.cm -2 .year -1 in spring, and 543.0 cal.cm -2 .year -1 in summer. A greater plant aerial biomass develops, mainly due to the establishing of Pinus pinaster and P. sylvestris forests. The highest average radiation values for the study area have been detected in orientations S, SE, SES, SOS and SO (246.8 cal.cm -2 .year -1 in winter, 303.4 cal.cm -2 .year -1 in autumn, 515.2 cal.cm -2 .year -1 in spring, and 582.6 cal.cm -2 .year -1 in summer); vegetation development is scarce mostly represented by shrub Cytisus purgans , and soils are shallow. Heights about 1300 m present smoother slopes, and intermediate average radiation values have been measured (212.0 cal.cm -2 .year -1 in winter, 242.2 cal.cm -2 .year -1 in autumn, 513.2 cal.cm -2 .year -1 in spring, and 580.5 in summer); the dominant vegetation is mainly Quercus pyrenaica , and below that height Castanea sativa woods are established.