Alnus crispa

About

Alnus alnobetula, the green alder, is a common shrub or small tree widespread across much of Europe, Asia, and North America. Many sources refer to it as Alnus viridis but this is a later name, synonymous with Alnus alnobetula subsp. alnobetula. The species was first described by Jakob Friedrich Ehrhart in 1783 as Betula alnobetula, while the name viridis was first used later, as Betula viridis, in 1785.

Summary from Wikipedia