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Acer glabrum - Torr.

Rock Maple

Author	Torr.	Botanical references	11, 60, 200
Family	Aceraceae	Genus	Acer
Synonyms
Known Hazards	None known
Range	Western N. America - Alaska to California, west to New Mexico.
Habitat	Edges of mountain streams, on rocks and in coniferous woods, 1500 - 2000 metres[82, 184].
Edibility Rating	2 (1-5)	Medicinal Rating	1 (1-5)

Physical Characteristics

A decidious Tree growing to 9m.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils, requires well-drained soil and can grow in heavy clay soil. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires moist soil.

Habitats

Woodland Garden; Secondary; Sunny Edge; Dappled Shade;

Edible Uses

Edible Parts: Inner bark; Leaves; Seed.

Edible Uses: Condiment.

Edible young shoots - cooked. They are used like asparagus[85]. The seedlings, gathered in early spring, are eaten fresh or can be dried for later use[213]. The dried crushed leaves have been used as a spice[257]. Seeds - cooked. The wings are removed and the seeds boiled then eaten hot[213]. The seeds are about 6mm long[82]. Inner bark[85]. No more details are given but inner bark is often dried, ground into a powder and then used as a thickening in soups etc or mixed with cereals when making bread. An emergency food, it is usually only used when all else fails[85].

Medicinal Uses

Antiemetic; Birthing aid; Cathartic; Galactogogue.

A decoction of the wood and bark is said to cure nausea[213]. Another report says that this is specifically the nausea caused by smelling a corpse[257]. An infusion of the bark has been used as a cathartic[257]. A decoction of the branches, together with the branches of Amelanchier sp., was used to heal a woman's insides after childbirth and also to promote lactation[257].

Other Uses

Containers; Fibre; Fuel; Preservative; Wood.

The leaves are packed around apples, rootcrops etc to help preserve them[18, 20]. A fibre obtained from the inner bark is used for making mats, rope etc[99, 257]. The bark has been used to make spoons, paint containers etc[257]. Wood - tough, hard, heavy, close grained, pliable[82, 99]. It weighs 37lb per cubic foot[235]. The wood can also be used as friction sticks[99]. The green wood can be moulded.[99] The wood is too small for commercial exploitation, though it makes a good fuel[99, 229]. It was often used by native North American Indian tribes for making small items such as snowshoes, drum hoops, bows and pegs[257].

Cultivation details

Of easy cultivation, it succeeds in any soil, preferring a good moist well-drained soil[11]. Prefers a sunny position but tolerates some shade[11, 200]. Grows well in heavy clay soils. Chlorosis can sometimes develop as a result of iron deficiency when the plants are grown in alkaline soils, but in general maples are not fussy as to soil pH. Hardy to about -25°c[184]. This species grows well at Kew, a specimen was 12 metres tall in 1967[11]. The tree is almost fastigiate[11]. Most maples are bad companion plants, inhibiting the growth of nearby plants[18, 20]. Trees are usually dioecious. Male and female trees must be grown if seed is required[226].

Propagation

Seed - best sown as soon as it is ripe in a cold frame, it usually germinates in the following spring. Pre-soak stored seed for 24 hours and then stratify for 2 - 4 months at 1 - 8°c. The seed has a hard coat and can be slow to germinate, often taking 2 years. The seed can be harvested 'green' (when it has fully developed but before it has dried and produced any germination inhibitors) and sown immediately. It should germinate in late winter. If the seed is harvested too soon it will produce very weak plants or no plants at all[80, 113]. When large enough to handle, prick the seedlings out into individual pots and grow them on until they are 20cm or more tall before planting them out in their permanent positions. Layering, which takes about 12 months, is successful with most species in this genus. Cuttings of young shoots in June or July. The cuttings should have 2 - 3 pairs of leaves, plus one pair of buds at the base. Remove a very thin slice of bark at the base of the cutting, rooting is improved if a rooting hormone is used. The rooted cuttings must show new growth during the summer before being potted up otherwise they are unlikely to survive the winter. It is very difficult to find suitable wood for cuttings.

Links

Permaculture.info Details of this plant in the Permaculture.info project, a community plant and permaculture database.

References

[11] Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981
A classic with a wealth of information on the plants, but poor on pictures.

[18] Philbrick H. and Gregg R. B. Companion Plants. Watkins 1979
Details of beneficial and antagonistic relationships between neighbouring plants.

[20] Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. 1978 ISBN 0-88266-064-0
Fairly good.

[60] Hitchcock. C. L. Vascular Plants of the Pacific Northwest. University of Washington Press 1955
A standard flora for Western N. America with lots of information on habitat etc. Five large volumes, it is not for the casual reader.

[80] McMillan-Browse. P. Hardy Woody Plants from Seed. Grower Books 1985 ISBN 0-901361-21-6
Does not deal with many species but it is very comprehensive on those that it does cover. Not for casual reading.

[82] Sargent. C. S. Manual of the Trees of N. America. Dover Publications Inc. New York. 1965 ISBN 0-486-20278-X
Two volumes, a comprehensive listing of N. American trees though a bit out of date now. Good details on habitats, some details on plant uses. Not really for the casual reader.

[85] Harrington. H. D. Edible Native Plants of the Rocky Mountains. University of New Mexico Press 1967 ISBN 0-8623-0343-9
A superb book. Very readable, it gives the results of the authors experiments with native edible plants.

[99] Turner. N. J. Plants in British Columbian Indian Technology. British Columbia Provincial Museum 1979 ISBN 0-7718-8117-7
Excellent and readable guide.

[113] Dirr. M. A. and Heuser. M. W. The Reference Manual of Woody Plant Propagation. Athens Ga. Varsity Press 1987 ISBN 0942375009
A very detailed book on propagating trees. Not for the casual reader.

[184] Phillips. R. & Rix. M. Shrubs. Pan Books 1989 ISBN 0-330-30258-2
Excellent photographs and a terse description of 1900 species and cultivars.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

[213] Weiner. M. A. Earth Medicine, Earth Food. Ballantine Books 1980 ISBN 0-449-90589-6
A nice book to read though it is difficult to look up individual plants since the book is divided into separate sections dealing with the different medicinal uses plus a section on edible plants. Common names are used instead of botanical.

[226] Lauriault. J. Identification Guide to the Trees of Canada Fitzhenry and Whiteside, Ontario. 1989 ISBN 0889025649
Very good on identification for non-experts, the book also has a lot of information on plant uses.

[229] Elias. T. The Complete Trees of N. America. Field Guide and Natural History. Van Nostrand Reinhold Co. 1980 ISBN 0442238622
A very good concise guide. Gives habitats, good descriptions, maps showing distribution and a few of the uses. It also includes the many shrubs that occasionally reach tree proportions.

[235] Britton. N. L. Brown. A. An Illustrated Flora of the Northern United States and Canada Dover Publications. New York. 1970 ISBN 0-486-22642-5
Reprint of a 1913 Flora, but still a very useful book.

[257] Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998 ISBN 0-88192-453-9
Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.

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