Acer macrophyllum

Acer macrophyllum, or Big leaf maple, is a large tree of the Aceraceae family growing up to 35 m tall with deciduous leaves turning yellow in the fall. When the bark is young it is smooth and green turning grey-brown and ridged with age. The trunk and limbs are often covered with mosses, lichens and ferns. Individual leaves are five-palmately lobed, 15-30 cm at the widest point, dark green on the upper surface, slightly lighter green lower surface and are arranged oppositely along branches. The flowers are small, measuring at only 3 mm across and greenish yellow in color. The inflorescence is composed of several flowers in a pendant cluster, typically appearing before the leaves. The fruit is a 3 to 6 cm wide samara, or paired winged seeds, golden-brown in color. The wings of the seeds form a V-shape when still intact and will spin like helicopter blades when airborne, aiding in seed dispersal.

The habitat of Big leaf maple includes low elevation moist sites generally coinciding with Douglas Fir trees (Pseudotsuga menziesii) having recently been disturbed by clearing, fire or logging. There is a strong competition between big leaf maple and conifer seedlings.

A. macrophyllum has a relatively fast growth rate and can grow up to 3 m in a single year.

In the Pacific Northwest, the trunks of A. macrophyllum can be so densely covered with epiphytes the bark is no longer visible. The moss layers can be thick enough that a “soil-like” layer is formed and will support roots of trees, known as ‘canopy roots.’

Traditionally, native people of the Pacific Northwest have used A. macrophyllum as an herbal remedy for moles, throat ailments and to ensure the growth of a full beard. The wood was used to make paddles and spindle whorls. The leaves were also very useful in everyday life as temporary containers. As a food, the seeds were sprouted and eaten and the sap was made into a weak flavored maple syrup.




Pojar, J. and A. McKinnon (1994) Plants of the Pacific Northwest Coast. Lone Pine Publishing, Washington, Canada.

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