Przestrzenny rozkład opadu cetyny oraz przyrostu pierśnicy w drzewostanach sosnowych rosnących po likwidacji ogniska reprodukcji cetyńców Tomicus piniperda (L.) i T. minor (Hart.)

The studies were conducted in the years 1992−1996 and 2001−2002 in the Węgle Forest Sub−district, Zagnańsk Forest District. The aim of the studies was to compare the spatial pattern of needle drop caused by Tomicus sp. and the dbh increment in pine stands before and after the liquidation of the sawmill and timber landing. Eight zones at different distances from the sawmill were distinguished: I – edge zone, II – 100 m, III – 300 m, IV – 500 m, V – 700 m, VI – 900 m, VII – 1100 m and VIII – 2000 m (control). The needle drops were collected from each zones using under−canopy plots of 4 m². in size and drilling into trees at the dbh using a Suunto increment borer. Research results confirmed the significant effect of the reproduction centres of Tomicus sp. on the losses in tree increments. The higher significant values of the needle drop during the functioning of the timber landing were related to the lower values of the dbh increment, and with the low needle drop following the liquidation of the landing the increment values were levelled in first zones.