A large, fast-growing deciduous maple reaching roughly 60-90 feet with a broad, domed crown, big five-lobed leaves, and the maple's signature paired winged samaras. Its honest virtue is toughness: it shrugs off wind, salt spray, and air pollution better than almost any other large tree, which has long made it a classic coastal and exposed-site shelterbelt. Its honest liability is that it self-seeds aggressively — outside its native montane range it has naturalised so freely that it is widely regarded as an invasive weed tree (notably across Britain and in parts of North America), with seedlings appearing everywhere. Native to the mountains of central and southern Europe and the Caucasus (POWO), it is best reserved for exposed, salt-laden, or polluted sites where its resilience earns its keep and where its prolific seeding is acceptable — and never near horse paddocks, because its seeds and seedlings are toxic to horses.