Environmental Drivers and Age Trends in Site Productivity for Oak in Southern Poland

Site productivity provides critical information for forest management practices and is a fundamental measure in forestry. It determined using site index (SI) models, which are developed two primary groups of methods, namely, phytocentric (plant-based) or geocentric (earth-based). Geocentric methods allow direct growth modelling, the SI predicted multiple environmental indicators. However, changes non-static factors—particularly nitrogen deposition rising CO2 concentration—lead to an increase productivity, may be visible as age trend SI. In this study, we model oak. For development model, used data from 150 sample plots, representing wide range local topographic conditions. A generalized additive was productivity. We found that oak depended predominantly on physicochemical soil properties—mainly nitrogen, carbon, sand, clay content. Additionally, value slightly shaped by topography, especially altitude above sea level, position. also detected significant relationship between stands, indicating long-term increasing oak, most likely caused climatic The explained 77.2% variation.