The dynamics of northern red oak (Quercus rubra L.) in managed forests of central Poland

Based on data obtained from the Information System of Polish State Forests (SILP), we compiled a register of segments with northern red oak within the area of the Grotniki Forest District. For all of these stands, the cover of Q. in the tree, understory (undergrowth and shrub layer) and herb layer was determined for at least three points and then rated on a ten-point scale (1 class – 10%, 2 class – 20%, etc.). The current distribution of Q. in all forest layers was analysed with respect to the type of forest habitat and stand age. Additionally, a prosperity index of northern red oak was calculated separately for two Forest Inspectorates and for all forest habitat types. The divisions with Q. in the Grotniki Forest District comprise a total area of 4,845,86 hectares, which represents 33% of the forest district’s area. In the Grotniki Forest Inspectorate 3,447,75 hectares (38% of the forested area) and in the Glowno Forest Inspectorate 1,398,11 hectares (25%) were inventoried. In all layers of the stands, the second and the third classes of coverage were the most commonly recorded, while Q. covered the largest surface area in the herb layer, which confirms that this species is spread continuously in the forest district’s stands. In the Grotniki Forest Inspectorate, Q. occurred most frequently in stands of the third age class, whereas in the Głowno Forest Inspectorate stands of the fourth age class had the highest rate of occurrence. The forest habitat in which Q. achieved the highest prosperity index is a moderately humid mixed coniferous forest.