The results of study done by numerous team of scientists led by Michał Bogdziewicz (Department of Systematic Zoology, AMU), with especially significant contribution from Jakub Szymkowiak (Population Ecology Lab, AMU), Mario Pesendorfer (Cornell Univ.), Idalia Kasprzyk (Uniwersytet Rzeszowski) and Łukasz Grewling (Laboratory of Aeropalynology, AMU).

Masting or mast seeding is a highly variable and synchronized seed production by population of plants. This mysterious plant reproductive behaviour is intensively studied. In our recent study, accepted in Ecology, we described the mechanisms leading to masting in oaks and European beech. It turns out, that highly similar reproductive patterns of these species are the result of completely different mechanisms.

Oaks produce similar number of flowers each year, and seed crop size is determined by the proportion of flowers that mature into seeds. That proportion is largely determined by the weather in spring. When spring is warm, oak tress flower in synchrony, which leads to effective pollen transfer, effective pollination, and high crop production. In contrast, cold springs desynchronize flowering which hampers pollination leading to reproductive failures.

In beech, spring temperature also regulates flowering synchronization. However, this has no effect on seed production. Beech trees show high variability in flower production, and high flower crops are coupled with high seed crops. Flower production is correlated with summer temperatures preceding seed production, i.e. when summers are hot trees initiate numerous flowers. This effect is modulated by plants resource state – if past years had small crops, trees produce biggest amounts of flowers. Interestingly, we found the same relationship for oaks, but it had no effect on crop size, since it is the flowering synchrony that matters in these species.

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