Bigleaf maple (Acer macrophyllum): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Acer macrophyllum Pursh in USDA PLANTS, maple family
Other names	Broadleaf maple and Oregon maple (Silvics)
Native status, USDA PLANTS	Native in Canada and the lower 48 states
Size, Silvics	Most mature trees are about 15 m (50 ft) tall and 50 cm (20 in) in diameter; large trees often reach 30 m (100 ft) and 90 to 120 cm (36 to 48 in); the largest known in 1977, in western Oregon, had a circumference of 1064 cm (419 in) at breast height, a height of 30.8 m (101 ft) and a crown spread of 27.4 m (90 ft)
Leaves, Silvics	Usually up to 30.5 cm (12 in) across, exceptionally 61 cm (24 in)
Form, Silvics	Rounded crowns on short, branching boles if open-grown; trees grown close together tend to have straight stems, clear of branches on their lower half to two-thirds
Age and roots, Silvics	The oldest attain ages of 200 years or more; the root system is shallow and widespreading, suited to shallow or saturated soils
Green weight of the wood, NRS-38	47 lb per cubic foot, without bark

Native range

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) says the native range of bigleaf maple extends from latitude 33 to 51 degrees north, always within 300 km (186 mi) of the Pacific Ocean. It is not found in southeastern Alaska or on the Queen Charlotte Islands, but grows on Vancouver Island at least as far north as Port Hardy. On the mainland the range is a continuous belt from near Sullivan Bay, British Columbia, to within 16 km (10 mi) of San Francisco Bay, California, including the western slopes of the Coast Ranges of British Columbia, the Olympic Peninsula, the Coast Ranges of Oregon and California, and the western slopes of the Cascade Range in Oregon and Washington. The handbook calls it less common south of San Francisco Bay, with extensive stands in the Santa Cruz and Santa Lucia Mountains and isolated groves along the southern California coast to San Diego County, and common on the western slopes of the Sierra Nevada north of the Yuba River.

Most of the standing sawtimber volume the handbook estimates is in Washington (about 19.6 million cubic m) and Oregon (about 18.0 million cubic m), and it gives 1.1 million cubic m for British Columbia, on the south coast and Vancouver Island.

Flowers, seed and sprouting

Silvics says bigleaf maple begins to produce seed at about 10 years of age and continues every year after. It is polygamous, with male and perfect flowers mixed in the same dense, cylindrical racemes. The flowers are greenish yellow and scented and appear before the leaves, from March at low elevations and in the south to June at high elevations and in the north. The fruit is a hairy double-winged samara with wings 3.5 to 5 cm (1.4 to 2 in) long, ripening in September and October. Most seeds are dispersed by wind between October and January.

The handbook says the species is not a pioneer that rapidly invades disturbed areas, but is often present in undisturbed stands and responds to disturbance with vigorous sprout growth. It describes silviculture of the species as usually involving control rather than culture, because vigorous stump sprouting is a problem in harvested stands. It says girdled bigleaf maples survive for several years and sprout.

Uses

Silvics calls bigleaf maple an excellent shade tree and one of the few commercial hardwood tree species on the Pacific Coast, small compared with its conifer associates. It says the wood is used in the furniture industry, especially for piano frames, and that the sweet sap can be made into syrup, though of lower quality than sugar maple syrup. Deer and elk browse twigs and young stems.

Wood

Silvics says the wood is neither as hard nor as strong as that of sugar maple. The Wood Handbook (FPL-GTR-282, 2021) puts bigleaf maple in the soft maple group with silver maple, red maple and boxelder, notes that bigleaf maple comes from the Pacific Coast while the others are found in the eastern United States, and says soft maple wood resembles hard maple but is not as heavy, hard and strong. Its uses for the group include railroad crossties, boxes, pallets, crates, furniture, veneer, woodenware and novelties. The group is also described on the red maple page. Table 5-3b has a separate bigleaf maple row, shown below.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.44	7,400	620
At 12% moisture content	0.48	10,700	850

The Wood Handbook states that specific gravity is based on oven-dry weight and the volume when green or at 12% moisture content. The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Diseases, insects and damage the handbook names

Silvics (1990) says fungi are responsible for much of the defect in bigleaf maple.

Wood-rotting fungi. Decay is seldom a serious problem in young undamaged trees, but the handbook says stem and branch wounds are invaded by Heterobasidion annosum, Fomitopsis pinicola, Polyporus berkeleyi and Inonotus dryadeus, which can reduce the tree to a hollow shell. See Heterobasidion and Inonotus dryadeus.
Root and butt rots. Overmature trees are often decayed by Armillaria root rot and by butt rots caused by Ganoderma applanatum and Oxyporus populinus; see Ganoderma.
Verticillium wilt. Occasionally kills forest trees but is called most serious on ornamental bigleaf maples.
Carpenter worm. Prionoxystus robiniae may seriously damage living maples of all sizes, particularly open-grown ones, and the larval tunnels degrade lumber.
Wood borers in dead wood. Powder-post beetles damage dead trees and maple products, and a roundheaded borer makes large burrows in dead or dying trees.
Animals and roots. Mountain beavers clip twigs and young stems, nematodes sometimes attack roots, and rodents, slugs and other invertebrates cause a high percentage of seedling mortality, with seed predation by small mammals also high.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.