Sapindaceae

Soapberry Family

Maple Trees

FAMILY: Soapberry family (Sapindaceae) – Acer genus. The maple family (Aceraceae) was recently integrated into the soapberry family (Sapindaceae).

SPECIES: #1 Rocky Mountain maple (Acer glabrum Torr.). #2 bigtooth or canyon maple (Acer grandidentatum Nutt.). #3 ashleaf maple or western boxelder (Acer negundo L.).

TO UTILIZE AS FOOD: The sap, inner bark, young leaves, young fruits, and seeds of species listed above are edible. All these parts are safe in moderation, but most of them taste awful, except for syrup made by concentrating the sap. The winter buds and flowers are presumably edible, but references to these parts could not be located.

Maple sap flows best in late winter on relatively warm days following freezing nights, and virtually stops flowing for the rest of the year. Flows can last from 5 days to 5 weeks. Peak flows only last a few days, occurring sporadically when environmental conditions are optimal. Trunk diameter should be at least 20 cm before tapping, and holes should be drilled on the sun-facing side. Raw sap is mostly water and about 1-4% sugar (primarily sucrose, fructose, and glucose). It tastes more like vegetable broth than syrup and lacks any hint of sweetness. It needs to be boiled down to about 1/4 of its volume to make a pleasant beverage, and about 1/40 of its volume to make syrup. One tree can yield 20-80 liters of sap, or about 1 liter of syrup over a few weeks. Maple syrup is a concentrated source of minerals including: calcium, potassium, iron, phosphorus, and magnesium. Insects crave maple sap, but they’re rarely a problem during “sugaring time” due to the cold temperatures of late winter. Bigtooth maple (A. grandidentatum) can be considered the western equivalent of sugar maple (A. saccharum).

Inner bark of all maple trees listed above is thin, tough, and difficult to acquire. These characteristics make it impractical to use as food because more energy is required to obtain it than what it provides in return. Maple bark is wood. It might pass for gum without the fibers, but it barely qualifies as food. Boiling won’t soften the bark. Fresh bark is moist and must be dried to make flour. Outer bark is easier to remove at the source rather than after the bark has dried. Inner bark yields a bland flour with a coarse texture. It’s essentially pure fiber. Mixing it with more wholesome flours is recommended. Maple sap is a much better resource than the inner bark. The inner bark can be gathered any time of the year, but it’s a wild food of minor importance.

Winter buds of maple trees can presumably be utilized as vegetables. Although no references specifically stating that the winter buds are edible were located, considering that the sap, inner bark, leaves, young fruits, and seeds are indeed edible, it should be safe to assume that the buds and other parts of maple trees can also be eaten. After remaining dormant through winter, the buds swell and grow into leaves, flowers, or branches. Winter buds are protected by scales. In Rocky Mountain maples, these scales are dull to vivid red, much more colorful than those of other species. Buds of ashleaf and bigtooth maples are green with brown highlights as they expand. The scales are weak and don’t pose any problems. At most, they put up a little resistance. Removing them is unnecessary. Winter buds are best collected as they begin to expand because they’re larger and filled with nourishment at that time. Sap flows right to the buds with the onset of warmer weather. Maple trees blooming indicate that spring is approaching. When eaten raw, the buds are bitter, astringent, reminiscent of lettuce, and “green-flavored.” Cooking offers an improvement and reduces astringency. The texture is chewable. Maple buds are apparently a good resource, but few, if any, references indicate they are edible.

Flowers of Rocky Mountain maple are presumably edible, but no references stating that they are edible were located. The petals are green, so they look more like sepals than petals. Other southwestern maples lack petals. Rocky Mountain maple flowers have a “deep green” flavor similar to lettuce, and a chewable texture. Since stalks are absent, or relatively short in this species, using the flowers like alfalfa sprouts is not an option. Other aspects are similar to the flowers of maples described below.

Flowers of bigtooth maple are presumably edible, but no references stating that they are edible were located. The flowers are inconspicuous. Except for the anthers imparting some yellow and the bud scales adding some brown, they’re unimpressive. When eaten fresh, the flavor is mild and the texture is chewable. Even the bud scales are chewable. Bigtooth maple flowers taste similar to lettuce overshadowed by bitterness. A flavor unique to maples is also apparent. Commercial foods lack a suitable comparison. Cooking offers an improvement, so bigtooth maple flowers serve well as cooked vegetables.

Flowers of ashleaf maple are presumably edible, but no references stating that they are edible were located. Male and female flowers are usually located on separate trees. Male flowers have long stalks that come in various colors including pink, yellow, and green. Female flowers have equally long stalks. In both genders, flowers hang downward in mop-like clusters. Male flowers taste slightly better and make a realistic substitute for alfalfa sprouts, realistic in texture rather than flavor. No cultivated foods taste quite like maple flowers and no wild foods provide a good comparison. Fresh flowers taste unappealing. Cooking offers a vast improvement. Ashleaf maple flowers make a decent cooked vegetable. Boiling turns the flowers dull green. Discarding the cooking water may be preferable to using it as broth since it tastes bitter. This bitter taste is barely noticeable in the cooked flowers. Any hairs are also unnoticeable. Gathering the flowers ranges from easy to difficult depending on tree size. Ashleaf maples can be shrub-like or towering giants. Steeping the pollen in hot water makes a sweet amber drink, but note that the pollen may be allergenic. Maple flowers are generally an early-season resource.

Leaves of maples listed above generally taste bitter when eaten fresh and reasonably good after cooking. Young leaves are light green. Various shades of reddish-purple may infuse the edges, and various amounts of hair may cover the surfaces. When hairs are present, cooking has little effect upon the hairs, so the final product may have a felt-like texture. Hairs can also be rather coarse. Leaves of Rocky Mountain maples tend to be less hairy than those of other species. Hairy textures may seem awkward to unaccustomed foragers “grazing” only upon store bought leaves. After overcoming any aversions to hairy vegetables, or acquiring a supply of hairless varieties, maple leaves can serve as a nourishing side dish at a time when few other wild foods are available. Cooking reduces astringency and offers an extra degree of safety. Diseases often affect maple leaves, so cooking is a wise precaution even when the leaves don’t appear compromised. Wilted maple leaves should never be consumed. Boiling yields a deep green broth. Flavor varies to some extent, but it’s consistently bitter. Maple leaves are a fair-quality wild food available in quantity early in the growing season.

Young fruits (samaras) of all maples listed above can be used in a similar manner. When eaten fresh, they generally taste bitter, acidic, and faintly like green beans. A flavor unique to maples is also apparent. It’s not a bad flavor, or at least not terribly unappealing. Young samaras are soft, tender, and completely chewable. Small amounts can safely be added to salads. Large amounts usually require cooking to reduce astringency. Hairs (when present) rarely pose any problems. Young samaras are borne with wings that soon become tough. Once that happens, only the portions surrounding the developing seeds remain usable. Cooking won’t adequately soften tough wings. A supply of samaras is usually within reach on the lower branches, and the samaras grow in clusters. Maple samaras are a decent wild vegetable available from April to July.

NOTES: Despite the abundance of maple trees in the southwestern mountains, my experiences with them are rather limited. Most of the experiences were based on trees from central and southeastern Utah and the San Mateo Mountains of New Mexico near Grants. All 3 species can be found in the Abajo Mountains of Utah. The entry on maple syrup was based on sap collected from trees in the northeastern United States. I didn’t sample the sap or seeds of any southwestern species, and I highly doubt that any of them are as forthcoming with sap as trees in the Northeast. Of all the parts, the flowers ranked among the best, yet they’re rarely mentioned in books about wild foods. Maple flowers are available in nearly unlimited quantities, which makes them a potentially valuable resource. I’m certain that Native Americans would not have overlooked such a resource, so why are maple flowers rarely mentioned in literature? Sap and nutrients flow to the buds, leaves, and flowers in spring, making these parts well worth the effort of gathering. I tried all these parts plus the inner bark and young samaras of all the southwestern species. The flowers consistently tasted milder than the buds and leaves. The inner bark and samaras also tasted mild, but these parts were tough, too tough to be practical sources of food.

IDENTIFICATION: The Acer genus is represented by about 20 species in the United States, of which only 3 grow in the Southwest, Great Basin, and Rocky Mountains. Maple trees are thornless and easily distinguished by observing the leaves and fruits. The leaves are arranged oppositely and turn beautiful shades of yellow, orange, and red in autumn. The fruits, commonly called samaras, keys, or helicopters, are winged and arranged in pairs. Ash trees produce similar fruits, except the fruits are not paired. In the Southwest, maple trees are found primarily in mountain habitats, often as a dominant part of the forest. No other trees are likely to be confused with maple trees.

Description of Rocky Mountain maple (Acer glabrum): FORM thornless shrub or tree about 3-11 meters tall; winter bud scales dull to bright red; LEAVES simple or palmately compound with 3-5 sessile leaflets; opposite; blades lobed or deeply cut; margins sharp-toothed; surfaces usually hairless (glabrous); FLOWERS regular, typically unisexual, ovary superior, and arranged in clusters that appear together with the leaves; stalks absent or short; sepals 4-6, free, and hairless; petals 4-6, free, yellowish-green, and similar to the sepals; styles 2; stamens 4-12 (usually 8); FRUITS samaras paired and winged; HABITAT mountainsides; blooming April to June. NOTES: The glabrum variety has simple leaves about 3-8 cm wide. A small-leaved variety called diffusum is also recognized, along with a 3-5-leaved variety called neomexicana in the southern extent of the species’ range. Autumn leaves are typically red.

Description of bigtooth maple (Acer grandidentatum): FORM thornless shrub or tree about 4-15 meters tall; winter bud scales gray, brown, or green; LEAVES simple; opposite; blades shallowly to deeply palmately lobed or sometimes merely wavy; margins with big, dull, rounded teeth; surfaces usually velvety; FLOWERS regular, typically unisexual, ovary superior, and arranged in drooping clusters that appear before or together with the leaves; stalks 10-30 mm long, and often with a few long spreading hairs; sepals 4-5, united at the bases, and hairy; petals absent; styles 2; stamens 4-12 (usually 8); FRUITS samaras paired and winged; HABITAT canyons and mountains, associated with oak and pine communities; blooming March to June. NOTES: Autumn leaves vary greatly in color, including vibrant shades of red, orange, and yellow.

Description of ashleaf maple (Acer negundo): FORM thornless tree about 5-20 meters tall; young twigs green and velvety; LEAVES pinnately compound with 3-7 leaflets; opposite; terminal leaflets evidently stalked; margins toothed or lobed; surfaces typically hairy; FLOWERS regular, typically unisexual, ovary superior, and arranged in drooping clusters that appear before or together with the leaves; stalks 15-35 mm long; sepals 4-5; petals absent; styles 2; stamens usually 4-6; FRUITS samaras paired and winged; HABITAT mountainsides; blooming March to June. NOTES: Several varieties are recognized based primarily on hair features. Autumn leaves are typically yellow.

REFERENCES: Couplan (pp. 300-301) indicates that the sap, inner bark, young leaves, young fruits, and seeds of species described above are edible. Gibbons (p. 177) states that the sap of all maple trees can be made into syrup.