Genetic evidence of stable northward extension of Pinus thunbergii Parl. forests in the Democratic People’s Republic of Korea

Japanese black pine ( Pinus thunbergii Parl.) with high salt tolerance may be an important constitutive element sustaining terrestrial ecosystem by playing a role of windbreak forests in coastal areas. Korean peninsula would be a notable region in clarifying distribution shift in Pinus species as it has northern distribution limit of Japanese black pine in Asia. Our main object was to verify genetic evidence of stable northward extension of P. thunbergii populations in DPR Korea. We investigated genetic background of 9 populations existing in Korean peninsula using nuclear SSR markers in relation to shifts in climate factors such as temperature and precipitation. Higher genetic diversity in east group (AR = 10.7 ~ 19.5) and west group (AR = 10.3 ~ 10.7) compared to north group (AR = 6.7 ~ 8.8) was found. When number of putative clusters (K) = 2, whole individuals were divided into west group and north-east group, and when K = 3, north-east group can be separated into north group and east group. Phylogeographic relationship verified by means of nSSR markers suggest that substantial increment of air temperature in DPR Korea allowed stable anthropogenic transfer of P. thunbergii forests and that artificial afforestation may bring rapid establishment of forest ecosystem owing to climate change.