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EN
Old Common Oaks (Quercus robur L.), often connected with myths and legends, are the largest trees occurring in Central Europe. The present paper describes twelve largest girthed specimens of the species growing in Poland. Authors, based on their own measurements and researches, prepared a ranking list of these unique trees and estimated their health condition. Moreover, their exact localizations in Mielno, Bąkowo, Piotrowice, Kadyny, Januszkowice, Zagnańsk, Rogalin, Nogat, Węglówka, Młock, Rudka and Karczmiska were described and most popular facts and stories from their history were given. The largest girthed Common Oak in Poland is “Napoleon” growing in Mielno (1042,5 cm in circumference), the second one is the oak from Bąkowo (1020 cm) and the third – “Chrobry” from Piotrowice. In total in Poland there are three specimens of Common Oaks with trunk circumference of more than 1000 cm, and five more with circumference between 900 and 1000 cm.
EN
Scots pine is the most common tree species in Poland with the share in the species structure of Polish forests exceeding 58%. The most dangerous pathogen of this species is Phellinus pini (Brot.) Pilát), which causes the white pocket rot (also called red ring rot) of pine heartwood. It is estimated that as a result of the fungus’s activity, about 8% of annually harvested pine stems is damaged and worthless. As the Ph. pini damages only heartwood, it is often recognized that its occurrence has no influence on the tree’s physiology. As it is still unknown whether the presence of this fungus also does not affect the cambium responsible for the radial growth. We carried out studies in Scots pine stands located in the Radziwiłłów Forest District (central Poland). We investigated trees from 5th and 7th age classes (Biała Góra and Budy Stare forests, respectively). A total of 60 trees were sampled (30 per site). Half of them were specimens showing advanced symptoms of sickness, while the others were healthy specimens with no evidence of infection. From each tree we took one increment core and measured the tree−ring widths. Average tree−ring width was in case of healthy trees significantly higher than for sick trees. The research showed a significant, even of a dozen percent, reduction in the annual increment of infected trees in relation to healthy trees growing on the same site. Presumably, unidentified chemicals secreted to the cambium by the growing mycelium of Ph. pini may be responsible for this. It also seems that this relationship is progressing with the growing age of tree stands and is particularly visible in old stands, for example in reserves. Thus, Ph. pini could be one of the factors limiting the natural age of pine trees and accelerating their dieback. We also found that the growth of trees affected by the disease is influenced by a factor other than climatic, disturbing the natural rhythm of their radial increments. This factor is most likely the presence of mycelium of Ph. pini in the wood.
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