Masting ontogeny: the largest masting benefits accrue to the largest trees

Abstract Masting, variable and synchronized seed production across years by a population of perennial plants, enhances reproductive efficiency through increasing pollination efficiency and decreasing seed predation. Masting represents a population-level phenomenon generated from individual plant behaviors. While the developmental trajectory of individual plants influences their masting behavior, the translation of such changes into benefits derived from masting remains unexplored. We used 43 years of seed production monitoring in European beech (Fagus sylvatica) to address that gap. The largest improvements in reproductive efficiency from masting happen in the largest trees. Masting leads to a 49-fold reduction in seed predation in large, compared to 20-fold in small trees. Masting yields an 8-fold increase in pollination efficiency in large, compared to 1.8-fold in small trees. Paradoxically, although the largest trees show the biggest reproductive efficiency benefits from masting, large trees mast less strongly than small trees. That apparently suboptimal allocation of effort across years by large plants may be a consequence of anatomical constraints or bet-hedging. Ontogenetic shifts in individual masting behavior and associated variable benefits have implications for the reproductive potential of plant populations as their age distribution changes, with applications in plant conservation and management.