Hansen's Northwest Native Plant Database


Acer macrophyllum (Big-Leaf Maple, Oregon Maple)

 

Kingdom

   Plantae – Plants

Subkingdom

   Tracheobionta – Vascular plants

Superdivision

   Spermatophyta – Seed plants

Division

   Magnoliophyta – Flowering plants

Class

   Magnoliopsida – Dicotyledons

Subclass

   Rosidae

Order

   Sapindales

Family

   Aceraceae – Maple family

Genus

   Acer L. – maple

Species

   Acer macrophyllum Pursh – bigleaf maple

Big-Leaf Maple (Acer macrophyllum) is the grande dame of the maple family. She generously spreads her arms to shade all who seek shelter under her glorious umbrella of large summer leaves. In autumn the lush green foliage turns to shades of gold and orange.

Make a unique natural outdoor living space. Plant two of these trees 15-17 feet apart. Enjoy them as they grow and when they are large enough, hang a hammock between them! In summertime, you'll lie on the most comfortable resting space imaginable. Cooled by a summer breeze and shaded by the Big-Leaf Maple's leaves--nature at it's finest!

In fall, she holds her leaves rather like a handkerchief she's done with and then drops them to the earth below. When she is finished dropping her discarded hankies she will have blanketed the ground with golden leaves to keep her roots warm. They will gather rain and will compost through the winter and in spring they will be rich new vitamins for the soil. Her leaves are so plentiful there will be compost to share with her neighbors--unless someone rakes up the leaves and takes them away.

If that happens, we hope the gardener will add them to the compost pile and bring them back in the spring, spreading the nutrients all around her trunk so the cycle of nature can come full circle.

A tree is known by its fruit; a man by his deeds.
A good deed is never lost; he who sows courtesy
reaps friendship, and he who plants kindness gathers love.
- Basil

Among the most handsome of maples, these impressive trees host a variety of moss, lichens and Licorice Ferns on their very bark, adding to their incredible beauty.

These rapidly growing maples are hardy from USDA 7-10 and grow along the Pacific coast to the west side of the Cascades and Sierra Nevada mountains. At maturity, they can reach 100,' with a 50' spread. The leaves reach 1' in diameter and blanket the forest in brilliant yellows and golds when they fall. Come spring and the branches will be laden with creamy yellow flowers.

Native plants such as Salal (Gaultheria shallon), Oregon Grape (Berberis) and Sword Fern (Polystichum munitum) work well for under story plantings.

 

Description: The “big daddy” of the Pacific northwest maples, Big-Leaf Maples tower above their native relatives generally reaching a height between 40 and 80 feet. The burgeoning canopy may extend out to 50 feet and its massive leaves are larger than any other maple.

With a name that translates into “large leaf” (macro=large, phylum=leaf), you cannot mistake the tree’s distinctive five-fingered leaves that broaden to over a foot in both length and width.

As the second most abundant tree in the Pacific northwest, the species proves its versatility and hardiness. This species requires a large space but it is unmatched as a shade tree.

Habit: The distinctive Big-Leaf Maple skeleton arises from a trunk that diverges into numerous long, thick vertical limbs. Within its dramatic canopy, the spreading and sometimes drooping branches create the perfect challenge for those who love to climb into treetops. Not to mention, the tree branches are hosts to a perfect “canopy community” of epiphytic plants, such as mosses and Licorice Fern (Polypodium glycyrrhiza), which tend to form thick mats covering the entire tree in a carpet of green. The trunk averages a diameter of 2 to 4 feet, but the immense mature trees may reach an astounding height of 100 feet and have a trunk stretching 5 feet across.

If you don’t have the leaves to aid identification, the Big-Leaf Maple can be distinguished from other tree silhouettes in winter by looking for the tree with grayish-brown to reddish-brown bark and a distinctive pattern of interlacing grooves and 4-sided raised ridges. Then follow one of its stout green twigs to the end and make sure it tapers to a sizeable ¼-inch terminal bud accompanied by 2 smaller buds on each side.

The broad-crowned maple bears leaves averaging 1 foot across that are divided into 5 deep lobes or points. Leaf margins are blunted with irregular, coarse teeth. Distinctive deep green leaves have shiny upper sides but become paler beneath.

The foliage turns pale yellow in the fall, and may sometimes exhibit a more dramatic show of warm orange and yellow tones. Big-Leaf Maple is the only North American maple species to exude a milky sap from its long leaf stalks. These long leaf petioles can attain a length equivalent to that of the leaf.

Big-Leaf Maple’s greenish-yellow flowers usually appear before the leaves. In spring the tree gives rise to fragrant bouquets of flowers that dangle together in leggy loose clusters. Each sweet-scented flower (there can be 10 to 50 flowers in each clustered inflorescence) measures about ¼-inch across.

By autumn the golden brown double samara develops, with wings measuring 1 to 2 inches long. Wonderfully fuzzy golden hairs cover its many samaras. As a prolific seed producer, this long-lived maple may produce up to one million seeds a year. Imagine the numbers of forest fauna that are sustained by its seeds over the some 250 years of its life.

Habitat and Range: Like most native maples, you’ll find the Big-Leaf dominating the landscape of many the riparian communities near streams and in river floodplains.

   

    

Photo credit: Walter Siegmund

 

Photo, left, credit: Daniel Passarini; Flower photo credit: Walter Siegmund; Wally Hansen at right holding bare root plants

     

Photo, eight, credit: Sarah McDfrom, Portland OR

The gregarious species can be found growing together in exclusive groups or scattered amid evergreen woods. The maple is common in foothills and valleys within southern British Columbia all the way through the Cascades down to the southern Sierra Nevada mountain range.

This versatile tree prefers the moist well-drained soils of riparian habitats but withstands both seasonal flooding and dry upland environments. The tolerant nature of this maple means the tree can reside in deep loamy soils as well as poorer rocky soils.

Big-Leaf Maple may establish in the full sun but also takes advantage of partially shaded sites. The quickly decomposing leaves are very high in nutrients and generate thick, rich soils beneath its canopy.

If you lift up a mass of maple leaf litter, you can be pleasantly surprised by finding a rare Megomphix snail or jumping slug! Many mollusk species prefer the maple’s protective layers of thick litter and nutritious humus.

The calcium-rich bark supports a veritable blanket of epiphytic plants that easily make a home within the interlaced furrows. In the moist canyons of mountain streams, mosses, lichens, and liverworts anchor into every niche and begin a mutually beneficial relationship with their host tree. While the maple provides the epiphytes with nutrients and habitat, the tree produces a network of aerial roots in its crown to tap into the abounding mats of nutrients and moisture created by the epiphytes.

Ornamental Values: Be sure you have enough space for this dramatically spreading tree. It has a reputation for dropping large limbs so be aware of plantings near buildings. Big-Leaf Maple roots also have a tendency to attack and invade water or sewer lines.

The long-lived shade tree grows rapidly when young but slows down as it matures.

For best success, plant the seedlings in an open, sunny or partially shaded area. Big-Leaf Maples thrive in well-drained soils, but do excellently in almost any soil type. The tree is hardy from zones 4 to 7.

Native Plant Gardening/Wildlife Habitat: The Big-Leaf Maple is a favorite of creatures great and small.

The numerous seeds that often remain on the tree into winter are eaten by songbirds such as evening grosbeaks, and small mammals.

The early blooming spring flowers are a great nectar source for bees and other insects.

Birds love to perch and nest within the broad network of branches.

Its long–lasting downed woody debris creates important habitat for cavity nesting birds.

The decaying wood attracts a host of insects that in turn feed a multitude of insectivorous birds.

The woody debris decomposes slowly in streams and rivers, creating perfect fish habitat.

Tender twigs, shoots and leaves are consumed by black-tailed and mule deer as well as elk.

For a successful garden, plant the trees along with its native companions Sword Fern (Polystichum munitum), Oregon Grape (Berberis nervosa), and Salal (Gautheria shallon). Its natural communities also include Douglas Fir (Psuedotsuga menziesii), Western Hemlock (Tsuga heterophylla), Vine Maple (Acer circinatum), and willows (Salix species).

Restoration and Mitigation Values: This majestic maple is great for re-vegetation of stream banks and steep slopes. Like its relatives, the massive root system of Big-Leaf Maple exhibits excellent soil binding properties. With its tendency to produce copious amounts of seed, planting just a few maples will ensure that many new generations of maples will carry on.

Historical and Cultural Uses: Big-Leaf Maple is the only western maple considered to have any real commercial significance. Large dense burls at the base of the trunk are esteemed for their attractive knotted grain patterns. The finely grained wood is fairly solid and can be fashioned into fine furniture, interior finishing, musical instruments, and cabinets as well as innumerable craft projects. Historically:

  • The wood was gathered for burning or carving into oars (it was called the “paddle tree”).

  • The leaves made temporary containers and to cover food cooking in the fire pits.

  • Rubbing leaves on prepubescent males would prevent thick whiskers.

  • The fibrous inner bark was worked into ropes and baskets.

Edible and Medicinal Uses: Of all the native northwest maples, Big-Leaf has the sweetest sap. However, the sugar content is still quite less than the famous sugar maple and you’ll need to gather a lot more sap to produce the same amount of sweet syrup.

The fragrant flowers are sweet tasting and make beautiful garnishes for salads and cakes. Raw shoots can be eaten fresh or dried and then boiled for survival.

Traditional decoctions of Big-Leaf Maple leaves were prepared by Native Americans to treat sore throats. The bark has also been described as a remedy for tuberculosis, which can be boiled to make a tea.

NOTE: Please use caution when preparing or eating any parts of a plant. Identification of the species and knowledge of a plant’s toxicity are both essential before using any plant species medicinally or otherwise. Please consult with a heath professional before attempting to treat any ailment.

Propagation Techniques: Seeds -- Big-Leaf species are early and heavy seed producers, seeds may be produced by age 10 or earlier if in an open setting. Collect the fuzzy golden seeds in fall, gather them as late in the season as possible but before the rains begin. They are quite easy to propagate.

You can sow the seeds directly into a cold frame, but you should do so as soon as possible. Many seeds don’t survive storage. For short storage place the seeds in airtight containers and store at close to freezing temperatures. Cold stratify the seeds for 1 to 3 months before sowing.

Try to aim for seed sowing in February or March. Allow the seedlings to remain in their mulched beds for at least two years before attempting to transplant.

Vegetative -- The numerous seedlings produced around a parent plant can be salvaged, but only remove those under 3 feet in height.

For a short comparison of northwest native maples, click here.

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Bibliography:

Thank you to the following references for their invaluable information:

Plants of the Pacific Northwest Coast by Pojar and Mackinnon (1994)

Western Forests, A National Audubon Society Nature Guide by Stephen Whitney (1985)

Flora of the Pacific Northwest by C.L. Hitchcock & A. Cronquist, University of Washington Press (1973)

Trees, Shrubs, & Flowers to know in British Columbia & Washington by C.P. Lyons, Lone Pine Publishing (1995)

Collecting, Processing and Germinating Seeds of Wildland Plants by J.A. Young and C.G. Young, Timberland Press (1986)

Trees to know in Oregon by Oregon State University Extension Service & Oregon Department of Forestry, Extension Circular 1450 (1995)

The Reference Manual of Woody Plant Propagation from seed to tissue culture by M.A. Dirr and C.W. Heuser, Jr., Varsity Press, Inc. (1987)

Landscaping for Wildlife in the Pacific Northwest by Russell Link, University of Washington Press & Washington Department of Fish & Wildlife (1999)

Naturescaping, A Landscaping Partnership with Nature by Oregon Department of Fish & Wildlife (2001)

US Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (2002, February) http://www.fs.fed.us/database/feis/

BCAdventure.com http://www.bcadventure.com/adventure/wilderness/forest/

Backcountry Rangers, Edible Sierra Nevada Plants Guide http://www.backcountryrangers.com/

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