Half a century of seed years in major tree species of Poland

Data on fruiting estimates for the six main forest species of Poland: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) KARST.), white fir (Abies alba MILL.), European larch (Larix decidua MILL.), oak (jointly Quercus robur L. and Q. petraea LIEBL.), beech (Fagus sylvatica L.), that is being regularly collected by the Polish Forest Service through an annual questionnaire sent out to all Forest Districts has been compiled onto a single drawing showing the magnitude and temporal positioning of seed years. A short discussion is given of the nature of recurrence of seed and cone crops in various parts of Poland.