Bigleaf Maple Acer macrophyllum

Bigleaf maple is the most common deciduous hardwood in west-side Pacific Northwest forests, and for mushroom foragers it’s one of the most productive trees to know. Dead and dying maples host oyster mushrooms, honey mushrooms, deer mushrooms, and a long list of bracket fungi. If you’re foraging in lowland forests west of the Cascades, you’re walking through bigleaf maple habitat — and you should be checking every downed log and standing snag.

The leaves are the largest of any maple in the world, up to 12 inches across with deep five-lobed palmate structure. Mature trees reach 50 to 100 feet tall with broad, rounded crowns and thick, deeply furrowed gray-brown bark. In wet PNW forests, bigleaf maples are often draped head to toe in mosses and licorice fern (Polypodium glycyrrhiza), creating their own micro-ecosystem on every branch.

Bigleaf maple thrives in moist, well-drained soils along stream corridors, riparian areas, and lowland forest bottoms. Its range runs from southern British Columbia to southern California, almost entirely west of the Cascade crest. In Washington and Oregon, you’ll find it in nearly every west-side drainage from sea level up to about 3,000 feet. It’s a pioneer species that colonizes gaps and edges, and a major component of mixed hardwood-conifer forests alongside red alder and Douglas-fir.

Unlike the conifers that dominate most PNW forests, bigleaf maple’s role in the fungal world is primarily saprotrophic. The wood decomposes readily, and fallen maples become long-term substrates for wave after wave of fungi. The tree also has cultural and commercial significance — the wood produces prized “quilted” and “spalted” figure used in lutherie and fine woodworking, and there’s a small but growing interest in tapping bigleaf maple for syrup (though it yields far less sugar than eastern sugar maple).

Associated Mushrooms

Bigleaf maple is a saprotroph’s paradise. The soft, fast-decomposing wood supports oyster mushrooms, bracket fungi, and a rotating cast of wood-decay species from fall through spring. Here are some of the most reliable associations.

Oyster Mushroom

Pleurotus ostreatus

One of the most common edible mushrooms on fallen bigleaf maple. Fruits in overlapping clusters on dead and dying wood, primarily in fall and winter but possible year-round in mild PNW weather.

Saprotrophic Edible Photo: Jeremy Collison

Deer Mushroom

Pluteus cervinus group

A classic wood rotter found on maple stumps, logs, and buried wood. Brown cap with free pink gills — a reliable indicator of well-decayed hardwood.

Saprotrophic Caution Photo: Jeremy Collison / CC BY-NC

Artist’s Bracket

Ganoderma applanatum

A perennial bracket fungus that may be found on living and dead maples. Brown woody shelf with a white pore surface — scratchable for drawing, hence the common name.

Saprotrophic Photo: Jeremy Collison / CC BY-NC

Late Fall Oyster

Sarcomyxa serotina

Fruits late fall through early winter on hardwood logs, especially maple and alder. Olive-green to yellow-brown caps distinguish it from true oysters.

Saprotrophic Edible

Honey Mushroom

Armillaria ostoyae

Both parasitic on living maples and saprobic on dead wood. Fruits in large clusters at the base of trees and on roots in fall. Must be thoroughly cooked — never eat raw.

Parasitic Saprotrophic Caution Photo: Harrison Reber / CC BY