EN
Scots pine stands in central Poland are now seen to be experiencing dynamic development of lower layers formed by oaks. The under−canopy natural renewal taking place in this way is sometimes characterised by good silvicultural quality, and could therefore be taken advantage of in the process of stand conversion. The study assess the quality of existing undergrowth layers of oak present in older stands of Scots pine, most especially from the point of view of their suitability for subjection to further silvicultural measures. The research material was collected in 10 objects where site type was classified as mesic mixed coniferous site type (BMśw) as well as in 11 ones with mesic mixed broadleaved forest (LMśw) site type. In each site type, 2 or 3 stands were selected to typify undergrowth layers aged 15, 20, 25 or 30 years. Assessment of oak undergrowth trees was made on the basis of 4−point scale in case of trunk or crown quality and vitality, and on a 3−point scale when vitality and the development trend were concerned. Next we selected the trees with future potential characterised by the highest quality from the point of view of all studied traits. A further determination concerned the influence on the traits in these best trees of the oak understorey that was exerted by biometric features of both the sheltering Scots pine stand and the undergrowth itself. The studied undergrowth oaks are of either very good or good quality. Around 90% of these young trees could be assigned to 1st or 2nd quality class with the respect of all of analysed traits. Furthermore, fertility of the site type was found not to have any influence on the quality of the young oaks. However, where the number of trees identified as having future potential is concerned, influence was demonstrated for density of trees in both stand and the undergrowth layer, as well as their height, breast−height diameter and basal area. Oaks forming the lower layer beneath Scots pine stands are thus characterised by good quality and growth trends, to the extent that this suggests allowing further growth to take place, with inclusion within the main stand or next generation.