Climate extremes have become the costliest risks to agriculture and are now threatening seed production of forests. Ninety percent of forests globally regenerate from native seed production. A continental scale analysis of climate extremes in North America and Europe finds a wide range of species responses to late freeze and drought that are better explained by geography than trait differences or phylogenetic conservatism. Drought responses have been greatest in dry habitats. Late freeze is decreasing seed production on both continents despite large differences in past effects.\ Tree fecundity or seed production per tree per year is estimated from North America and Europe. Estimates come from two data types. Seed-trap (ST) data derive their fecundity estimates from seeds collected in traps on mapped inventory plots. Inference includes a dispersal kernel and species assignment as most seed-traps are resolved to the genus level. This genus-level resolution explains storage of data by genus. Crop-count (CC) data derive their fecundity estimates from a subset of the full crop paired with an estimate of the fraction represented by the count. The estimate for an individual tree year integrates ST CC or both data types.
