Effects of climatic conditions on annual tree ring growth of the Platanus x hispanica "Acerifolia" under urban conditions of Szczecin

Szczecin harbours Poland’s largest London plane tree population. The London plane trees growing in Szczecin’s Żeromski Park were subjected to dendroclimatological research (analyses of signature years and response function). The study was based on a composite site chronology, signed ZER, spanning 105 years (1900–2004); the mean annual tree ring growth was 2.59 mm. Precipitation, particularly that in late winter- early spring and in the summer months was found to be a factor decisive for the tree’s cambial activity. A high sum of precipitation during the periods mentioned induced positive growth responses in the trees. Thermal conditions during the growth period proved to be another factor controlling the annual tree ring growth, as shown by linear relationships. The tree ring growth-climate relationships in the population under study as well as the between-parks differences in the London plane tree response can be explained by differences in habitat conditions. The trees under study grow in the vicinity of a busy, frequently repaired street and are surrounded by pavement and/or hardened road surface, which greatly limits the infiltration of moisture supplied by precipitation.