Diameter growth performance of northern red oak (Quercus rubra L.) in northeastern Hungary

Northern red oak (<i>Quercus rubra</i> L.) isanimportant introduced tree species inHungary, particularly inthe Nyrsg region. This study investigates its diameter growth (<i>DBH</i>) insix forest subcompartments, with stand ages ranging from 20 to71 years. 5- and 25-year diameter increments were calculated. The distribution ofdiameter and diameter increment values was also determined. The results show significant growth across all sites. For example, quadratic mean diameter (<i>QMD</i>) increased from 16.4 cm to30.4 cm over 25years inthe forest subcompartment Encsencs 12A, and from 20.3 cm to38.4 cm infehrt 2A. Five-year <i>DBH</i> increments ranged from 1.8 cm (±0.8) inolder stands to4.2 cm (±0.5) inyounger ormiddle-aged stands. The findings confirm <i>Q. rubra</i>'s capacity for steady diameter growth in northeastern Hungary and contribute valuable growth data for future yield modelling and forest management strategies.