Time series modelling of relationships between climate and long-term radial growth of loblolly pine

Abstract

Time series techniques were utilized to evaluate the influence of selected climatic factors on basal area increment growth of loblolly pine (Pinustaeda L.) in rural Alabama and to address the possibility of a changing growth trend. This study is unique in its application of these techniques to an important southern United States timber species. An important asset of the study is the availability of long-term weather records from a weather station only 0.5 km distant. Basal area increment from 1906 to 1986 was modelled using an autoregressive integrated moving average model. Significant predictors of annual increment are previous annual increment, average temperature in June, precipitation in May, June, and August, the annual drought index for southern pine, and the Palmer drought severity index value for August. The best predictor variable examined was the August Palmer drought severity index value. Basal area increment was examined for interventions indicating a changing growth trend. No significant (p ≤ 0.05) interventions were observed in the climatically modelled series.