Beech seeds in Polish forests show declining mass and increased emptiness

A 20-year study of beech seeds collected in Polish forests reveals a significant decline in seed mass and an increase in empty seeds. Researchers from the Institute of Dendrology of the Polish Academy of Sciences, Adam Mickiewicz University in Poznań, and the Forest Research Institute analyzed over 13,000 batches from 380 forest districts.

The findings, published in Forest Ecology and Management, show that the mass of one thousand seeds has decreased by approximately 10 percent over the two-decade period. Additionally, the frequency of batches containing a high number of empty seeds—those with less than 85 percent full, well-developed seeds—has risen from roughly 1 percent to 14 percent.

While embryo viability remained stable and showed some correlation with seasonal weather patterns, the decline in seed mass and the increase in empty seeds do not appear to be clearly linked to climate change, mast year frequency, or local environmental factors. The exact causes for these changes remain unknown.