Yellow Birch is a large native aromatic deciduous tree with a straight trunk and broad rounded crown of drooping branches growing 70 to 100 feet high. The crown will be irregularly narrow in dense woods.
Bark is a smooth shiny reddish-brown that separates into papery curly strips and with age becomes tan to golden-yellowish or silver gray with expanded lenticels, fissures and scaly plates. The golden yellow of a typical mature tree is how the common name came about.
Twigs are greenish-brown to reddish-brown, slender, with hair when young; smooth and brown later, with scattered light colored lenticels, and usually have small glands. The glands and the inner pith give off a wintergreen odor and taste when crushed. Buds are ovoid, sharp pointed, reddish-brown with a fringe of hair on the scale margins.
Leaves are alternate, simple, elliptical, 4 to 6 inches long with a pointed tip, rounded to heart-shape base and a sharp double-toothed margin, 9 to 11 veins per side, dark dull green above, light yellow green below, hairy when young. Leaves often have resinous glands along the vein which also give off the wintergreen odor when crushed. There are small stipules at the base of the leaf stalk. Leaves usually occur on short spur shoots of the twig, 2 per shoot. Fall color is a bright yellow.
Flowers: The tree is monoecious, that is with separate male and female flowers. Male flowers (staminate) occur in a cluster of 3 to 6 reddish-green catkins, that appear on the twigs in the fall and then elongate up to 3 - 4 inches long, in the spring, near the ends of twigs, in hanging clusters taking on a yellow-purple color. The individual flowers are only 1/8 inch long, are yellowish with 2 stamens, a 4-lobed calyx and are in groups of 3 and somewhat obscured by small bracts. Female flowers (pistillate) appear with the leaves and are reddish-green upright catkins, about 3/4 to 1-1/4 inches long at maturity, back of the tip on the same twigs. Each flower has an ovary, a pair of styles but no calyx or petals and occur in groups of 3 and are also obscured by bracts. Catkins are also referred to as 'aments'.
Fruit: Pollination is by wind. Flowers mature to a short-stalked upright cylindrical non-woody cone-like structure, 3/4 to 1-1/4 inches long, brownish in color with many 3-lobed hairy scales, each scale containing a 2-winged nutlet, the wings narrower than the nutlet, which mature in the fall and disperse by wind and water in the winter. These cone-like structures will usually remain on the twig after seed release. Seeds are not produced on young trees and once production starts crops are heavy once every 10 years and much lighter on intervening years.
Habitat: Yellow Birch grows in many environments from moist marsh areas to uplands. It has adapted to landscape plantings and grows well if adequate moisture is provided. Full sun is best- it tolerates some shade but not deep shade. It can be a long-lived tree, unlike the Paper Birch. It does not spread from its root crown, but will re-sprout from a stump although those sprouts are usually short lived. It's root system is broad and shallow. The plant will hybridize with Paper Birch but unlike Paper Birch it is a dominant species.
Names: The genus, Betula, is the Latin word for the birch tree. The species, alleghaniensis, refers to the Allegheny Mountains where the tree is prevalent. In the 19th Century the species was classified as B. lutea, from the Latin lutum for 'yellow'. The name 'birch' itself is derived from an old Teutonic word. The author name for the plant classification - ‘Britton’ is for Nathaniel Lord Britton (1859-1934) American botanist and taxonomist, co-founder of the New York Botanical Garden, signatory of the American Code of Botanical Nomenclature and co-author with Addison Brown of Illustrated Flora of the Northern United States, Canada, and the British Possessions in 1896.
Comparisons: The Yellow Birch has some similar characteristics to Sweet Birch, B. lenta - leaves that have a rounded to heart shaped base and 8+ pairs of lateral veins on the leaf. But Sweet Birch has bark that is a reddish-brown to black and the scales of its cones do not have hair on the margins. Other birches have leaves not usually rounded or heart-shaped at the base and have fewer than 8 lateral veins, and the scales of the cones fall away quickly rather than persist into winter. See leaf comparison photo below.
Above: 1st photo - A fairly mature tree. 2nd photo - Fall leaf color.
Below: 1st photo - Twig buds are ovoid, sharp pointed, reddish-brown with a fringe of hair on the scale margins. Variations in tree bark: 2nd photo - bark of a younger stem, reddish brown with the lighter color lenticels clearly visible. 3rd photo - very old trunks that are more scaly and a lighter color cast - typically a dark golden yellow or bronze.
Below: 1st photo - Branches containing the upright female catkins, the hanging male catkins that have shed their pollen and some remaining old seed cones from the prior season. 2nd photo - The male catkins elongating in the spring prior to shedding pollen.
Below: 1st & 2nd photos - The upright female catkin containing the female flowers.
Below: 1st photo - A mature seed cone - note the fine hair on the scale edges. 2nd photo - The mature seed cone has numerous 3-lobed hairy scales, each scale containing a 2-winged nutlet (upper left in photo), the wings narrower than the nutlet itself.
Below: 1st photo - A branch tip with the male catkins at the tip and the female catkins back from the tip - typical arrangement. 2nd photo - Leaves are simple with a pointed tip, rounded to heart-shape base and a sharp double-toothed margin, 9 to 11 veins per side.
Below: 1st photo - Young twigs has whitish hair, light colored oblong lenticels, glands and glandular hair (the dark spots). 2nd photo - The leaf stalks have similar properties plus small stipules at the base of the stalk.
Below: A comparison of leaves of the five Birch species described on this site.
Notes: Yellow Birch is indigenous to the Garden, Eloise Butler catalogued it on April 29, 1907. Gardener Cary George planted additional ones in 1994 and 1998. Garden Curator Susan Wilkins added additional plants in 2008. In North America it is found from Minnesota and Ontario eastward to the coast and south as far as Tennessee, Georgia and South Carolina. Within Minnesota it has been found in the wild in counties of northeastern part of the state down through the metro areas and the a few counties in the SE tip. This is the western edge of the plants range in North America. It is much more prevalent in neighboring Wisconsin.
Heritage Tree: The large Yellow Birch on the wetland trail is listed as a Minneapolis Heritage Tree for Champion Size.
Eight species of birch are recorded from surveys in Minnesota. Three of them are crosses formerly reported but there are no known populations. The other five are native and are: B. alleghaniensis, Yellow Birch; B. cordifolia, Heart-leaved Birch; B. nigra, River Birch; B. papyrifera, Paper Birch; and B. pumila, Bog Birch. All but B. cordifolia are in the Garden.
Uses: Yellow Birch is an important lumber source, the wood being strong and close grained making it suitable for use in cabinetry and furniture. Prior to the introduction of synthetics, Oil of Wintergreen or Birch Oil, was once extracted in great quantities. It was used to flavor medicines and candy. The Yellow Birch produces this oil in less quantity per tree than the Sweet Birch. This has been replaced by a manufacturing process that creates the oil from wood alcohol and salicylic acid. As to further medicinal use, there is limited literature on Native and folk use of the tree for treating ailments.
Botanist Francois Michaux (son of Andre) wrote in his North American Sylva of 1819-21 (Ref. #26c): "It is a beautiful tree. It is particularly remarkable for the color and arrangement of its epidermis, which is of a brilliant golden-yellow, which frequently divides itself into very fine strips, rolled backward at the ends and attached in the middle. The wood of the Yellow Birch is inferior in quality and in appearance to that of the Black Birch [B. lenta] and never assumes as deep a shade; but it is strong, and, when well polished, makes handsome furniture. In Nova Scotia, and in the district of Maine, it is found by experience to be everyway proper for that part of the frame of vessels which remain always in water. In the district of Maine it is preferred for the yokes of cattle and for the frames of sledges; and in Nova Scotia the young saplings are almost exclusively employed for the hoops of casks."
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"