Local adaptation is a key consideration for forestry related activities, particularly when seed is transferred from one seed zone to another for afforestation. Locally adapted trees may show differences in growth when planted in sites other than their origin. Scots pine is one of the most valuable commercial timber trees with higher rate of growth. Although growth differences have been noted in the past, the extent to which Scottish Scots pines are locally adapted at the population level has remained unclear. In this dissertation, some aspects of local adaptation in pine are discussed and previous work is reviewed (essay review) and then (research paper) an experimental trial is presented in which genetic differences among populations and families from the Scottish Scots pine distribution are tested using growth as a measure of performance. Differences are related to climatic variables from the sites of origin of the seed. Finally, the role of provenance/progeny trials or common garden tests in researching local adaptation is also discussed.