Understanding tree growth in relation to environmental conditions is essential, particularly in the context of climate change,where rising temperatures, frequent droughts, and disturbances threaten forest health and productivity. This study useshigh-resolution data from four intensively monitored Picea abies stands in Austria (2010-2020), with dendrometers recordinghourly stem increments on 10 trees per site, allowing for detailed analysis of growth responses to environmental changes.For thispurpose we tested different generalized additive mixed models (GAMs) using environmental data collected on site. The best modelconsisted of combinations of soil moisture (SM) and soil temperature (ST) data. Furthermore we analysed how the relationshipsestablished differ for three different times during the growing season. We found that high SM consistently had a positive effect ontree growth, wheras the effect of ST varied depending on the timing.Our findings underscore the importance of monitoring soilconditions, particularly for species like Picea abies, which are known to react more sensitive to environmental changes due totheir shallow rooting systems and vulnerability to drought.