Acer macrophyllum aka Bigleaf Maple

Acer macrophyllum is known as bigleaf maple or Oregon maple. This large tree belongs to the Sapindaceae family. It sheds its leaves each year. Its native range runs from British Columbia to southern California. It grows in woods, beside streams, and on rocky slopes. Most native sites lie near the Pacific coast. Garden trees reach 40–75 feet [12.2–22.9 metres] tall and wide. Some trees reach 100 feet [30.5 metres] in height. The crown becomes broad and round with age.

Trees in open ground form low branches and rounded crowns. Those in dense woods grow taller and straighter. Young bark is smooth and gray-brown. Older bark darkens and forms deep grooves and joined ridges. Thick twigs change from green or red to gray-brown. The tree can sprout from its base or cut stump. Its leaves grow in pairs and have five deep lobes. They span about 0.5–1 foot [0.15–0.30 metres], sometimes more. Their upper faces are dark green, with paler undersides. Leaf stalks release milky sap when broken. Fall brings yellow, gold, and orange tones.

Small, scented, green-yellow flowers hang in clusters during spring. Missouri Botanical Garden gives the bloom period as April to May. Male and female flowers can share the same cluster. The fruit consists of paired samaras with hairy seed heads. Their wings meet at a narrow angle. Seeds turn tan when ripe, and fruit appears in fall. Birds and small mammals eat the seeds. Deer and elk feed on young trees.

Give this maple sun or partial shade and soil that drains well. It grows best with moist soil and cool summers. It prefers slight acidity but accepts several soil types and pH levels. It also tolerates somewhat dry ground. Hot, humid southeastern US summers can limit its performance. Missouri Botanical Garden lists USDA zones 6–7; RHS rates it H6. Its size suits parks and large grounds where shade is needed. Shallow roots can damage paths and drives. Mosses and ferns often cover its trunk in moist western woods.

Serious pest problems are not usual, but some troubles occur. These include aphids, mites, caterpillars, and horse chestnut scale. Diseases include powdery mildew, Verticillium wilt, leaf scorch, and honey fungus. People use the wood for furniture, cabinets, floors, and veneer. Sap can make syrup, though it contains less sugar than sugar maple sap. Plants For A Future lists flowers, leaves, shoots, seeds, and inner bark as edible. That source reports no known hazards.