Differences in δ13C and diameter growth among remnant Scots pine populations in Scotland

Abstract

Published data suggest that differences in wood cellulose carbon isotope composition (δ13C) and xylem ring width among natural populations of Scots pine in Scotland (Pinus sylvestris L.) are attributable to the persistence of palaeotypes of various post-glacial migratory origins. We assessed differences in wood cellulose δ13C and ring width among Scottish Scots pine populations grown in a clone bank and in natural stands at various locations in northern and central Scotland. Ring width and wood cellulose δ13C varied significantly among natural stands. Potential water deficit was positively correlated with wood cellulose δ13C and xylem ring width in the natural stands. Neither wood cellulose δ13C nor xylem ring width of clone bank trees correlated with any climate variables at the sites from which the trees originated, indicating little adaptation to climate for these traits. Xylem ring width showed a site x population interaction for the growth sites (i.e., natural stands versus clone bank), but wood cellulose δ13C did not. These results suggest that climate variation in Scotland has not resulted in significant genetic variation in wood cellulose δ13C or xylem ring width in post-glacial populations.