A vigorous European maple with milky sap, widely planted in cities for its dense shade and now invasive in much of North America.
Where it grows
Norway maple is native from the Pyrenees and Norway east to the Caucasus and Iran. Introduced to North America in the 18th century as a street tree, it has spread aggressively in the northeastern United States, where it now displaces native sugar maple from many woodlands.
How to recognise it
The five-lobed leaves are similar to sugar maple but larger, broader than long, and tipped with bristle-like points. The clearest field mark is the milky white sap exuded when the leafstalk is snapped — sugar maple sap is clear. The bark is grey, shallowly furrowed in a network of low ridges. Spring flowers are bright greenish-yellow.
Uses
The dense, pale wood is used for furniture, butcher blocks, and kitchenware, particularly in northern Europe. Fast growth, dense shade, and tolerance of urban pollution and salt made it a defining American street tree of the mid-20th century.
Conservation
In its introduced range Norway maple is now classed as invasive in several states because it shades out native wildflowers and prevents oak and sugar maple regeneration. Removal programmes are underway in many parks and reserves.