Climate change is manifested by an overall increase in air temperature and a significant change in the distribution and amount of precipitation (Auer et al., 2007; IPCC 2014; Gao and Giorgi, 2008). Furthermore, it is characterized by an increased frequency of extreme events (droughts, floods, devastating winds) that are a major cause of natural disasters (Beniston et al., 2007; Lenderink and Van Meijgaard, 2008). Lowland floodplain forest ecosystems are among the most sensitive to climate change (Horner et al., 2009; Pittock et al., 2008) because they are directly dependent on the hydrological regime of lowland rivers. Natural floodplain forests with old-growth characteristics practically no longer exist in Europe (Sabatini et al., 2018). Such forests are considered one of the two most endangered forest habitat types (Schnitzler, 1994; Cox and Temple, 2016). Pedunculate oak (Quercus robur L.) and narrow-leaved ash (Fraxinus angustifolia Vahl) are species that dominate in the lowland forests of southeastern Europe, including Croatia. The aim of this study was to determine the influence of climatic factors on the dynamics of pedunculate oak and narrow-leaved ash stands in the Posavina area, with emphasis on different microhabitat conditions (wet, fresh, dry). Another aim was to determine whether there is a difference in climatic sensitivity of the obtained oak chronologies with the existing European chronologies and to investigate the potential of pedunculate oak chronologies from old-growth stands. The results of climatic sensitivity (eastern and western) and 4 groups of ash within the area of central Posavina (west). Narrow-leaved ash from the lowest parts (wet) is most sensitive to climatic factors and most vulnerable to climate change, while the situation with oak is more favorable. Compared to European chronologies, oaks are less sensitive to climatic factors and form a separate group together with some other chronologies from the region. Chronologies of old-growth stands show great potential in the reconstruction of extreme events throughout history and in the reconstruction of certain climatic factors. relations reveal the existence of 2 completely separate groups of oaks according to climatic