The age of mature Abies alba Mill. trees in the Białowieża Forest and the onset of their seed production

Scattered groups of Abies alba Mill. of various ages occur in the Polish part of the Białowieża Forest; however, the true age of the mature stands remains uncertain. The aim of this study was to determine the actual age of a mature silver fir population (subcompartment 498 Ci) of unknown origin and to estimate the onset of seed production. Because age estimation based solely on tree size is unreliable in shade-tolerant species, we applied an integrated approach combining dendrochronological analysis with empirical age–height data derived from natural regeneration. Increment cores were collected from 29 trees as close as possible to the root collar (8–52 cm above ground level). The time required for trees to reach the sampling height was reconstructed using growth data obtained from 92 seedlings and saplings. The results indicate that the median reconstructed year of establishment was 1928, corresponding to an estimated age of 98 years in 2026. An indirect estimate of the age at which seed production began, based on the oldest regeneration individuals recorded, was 61 years. These findings provide preliminary evidence that the environmental conditions of the Białowieża Forest are conducive to the growth and reproduction of silver fir.