Direct and Carry-Over Effects of Temperature Drive Height Increment of Scots Pine in the North-Eastern Baltic Sea Region

Abstract

In the eastern Baltic region, the abundance of Scots pine (Pinus sylvestris L.) has been predicted to shift due to changes in height growth and competitiveness. Under such conditions, the relationships between tree growth and meteorological/climatic conditions can provide valuable information on the ecological plasticity and adaptability of local populations. Regarding the climatic dependence of productivity and competitiveness, height increment is an informative proxy, although data gathering is laborious. In this study, meteorological sensitivity of the height increment of Scots pine across the climatic gradient of north-eastern Baltic region was assessed by the means of timeseries deconstruction and generalized additive regression. Previously published time series from sites in Latvia, Estonia, and Finland were reanalysed. The local linear weather–growth relationships showed gradual changes in sensitivity to low summer temperature to conditions related to water availability in summer in Finland and the Baltics, respectively. The regional generalization of responses indicated the prevalence of temporary and spatially stationary effects of temperature in winter and summer, which had a complex influence (direct and carry-over effects). The prevailing linearity of the regional responses suggested that, regarding height growth, the studied populations appeared adapted to a wider climatic gradient than the studied one.