Overview
The Bigleaf Maple (Acer macrophyllum) is the undisputed giant of the maple genus, native to the dripping temperate rainforests of the Pacific Northwest. True to its name, this monumental hardwood produces the largest leaves of any maple on Earth—often spanning over a foot across—and is globally celebrated as a ‘vertical rainforest’ whose massive, moss-draped limbs support tons of living epiphytic ferns and lichens.
Biology and Physical Characteristics
Acer macrophyllum grows with a colossal, spreading crown and thick, gnarled limbs covered in ridged grey-brown bark. Its deeply five-lobed, palmately veined leaves measure 15 to 30 cm (6 to 12 in) across, with record leaves exceeding 60 cm. In early spring, before the leaves expand, the tree produces drooping cylindrical clusters of fragrant, greenish-yellow flowers rich in nectar, followed by large, fuzzy winged samaras.
Behavior and Ecology
In the humid coastal rainforests of the Olympic Peninsula and Vancouver Island, an individual Bigleaf Maple functions as a complete hanging ecosystem. Its massive horizontal branches support colossal gardens of epiphytic mosses, liverworts, and licorice ferns that can weigh up to four times more than the tree’s own foliage. The tree even grows canopy roots high into this moss to absorb water and nutrients directly from the air.
Conservation and Human Impact
Classified as Least Concern by the IUCN, the Bigleaf Maple is abundant throughout Pacific Northwest watersheds. Highly prized in woodworking for its fine, figured ‘quilted’ and ‘fiddleback’ grain used in premium acoustic guitars, it is also tapped locally to produce delicious, rich specialty maple syrup.
Interesting Factoid
The Bigleaf Maple grows canopy roots high up in its own branches: its upper limbs are so heavily covered in thick mats of wet moss that the tree sprouts roots straight out of its bark to drink water from its own moss gardens.