The Carlisle Mosquito Online

Friday, November 5, 2010


Swamp White Oak

As a human food source, acorns may leave something to be desired.
(Photo by Kay Fairweather)

A feature of any walk sponsored by the Trails Committee is food. I am not referring to foraged food found along the way but to the snacks served at the walk’s end. The mushroom walk at Foss Farm last Sunday was no exception. We found very few edible mushrooms but in typical Trails Committee style, we were treated to hot cocoa and cookies. What’s more, Steve Tobin had prepared candied acorns (harvested from Swamp White Oak). I felt like a squirrel at Halloween – dressed up as a human.

Name: The Swamp White Oak, as its name suggests, is a member of the “white” oak group of oaks and it likes to grow in the wet soil of river banks, flood plains, and swampy areas subject to flooding. All oaks are in the genus Quercus. Swamp White Oak is Quercus bicolor, one of the 50 species listed in the Field Guide to Native Oaks of Eastern North America. The species name, bicolor, refers to the difference in color between the upper and lower surfaces of the leaf; green on top and whitish below.

Where found: Steve collected the acorns along the River Trail in the Great Meadows National Wildlife Refuge, where they are plentiful. The range of the Swamp White Oak is the northeast quadrant of the US.

Distinguishing characteristics: White oaks can generally be distinguished from red oaks by the absence of bristles on the leaf lobes. Also, the interior of a white oak acorn shell is smooth and bald while a red oak acorn shell is hairier in the interior. Leaves of the Swamp White Oak have five to ten relatively shallow lobes on each side of the midrib, almost parallel side veins, and the color is markedly different on the top and bottom surfaces. The acorns have a long slender stalk which frequently bears two acorns. Acorns of many other species have very short stalks. Swamp White Oak is known to hybridize with several other species of oak making an absolute identification beyond the reach of most of us.

Acorns: The Swamp White Oak produces a large crop of acorns every 3 to 5 years with smaller crops in the other years. Acorns are a well-known source of food for squirrels and other rodents, and also White-tailed Deer and Black Bears. The Northeast Area of the U.S. Forest Service quotes a study done in Wisconsin that showed Swamp White Oak acorns making up 27% of the diet of wild ducks.

Food for humans: Acorns have a history of being used as food by Native Americans. The acorns of white oaks are sweeter than those of red oaks and contain much less tannin. Steve Brill in the Wild Vegetarian Cookbook reports that the process of leaching the bitter tannin from red oak acorns is not practical. Steve (Tobin) boiled his Swamp White Oak acorns in four changes of water before rendering them palatable. The final batch of leaching fluid was a sugar syrup after which the acorns were dusted with sugar. I found them to be sweet from the sugar but a bit earthy in a way that might be an acquired taste.

Steve Brill says they are one of “our least appreciated food sources” and I have an idea of the reason for it. I have long wanted to make acorn ice cream and Steve brought me a bag of acorns. Despite some misgivings I decided to give it a go. So far I have subjected them to eight leaching sessions and am not yet ready to commit a couple of cups of cream to them. A more practical use might be to grind them into flour and add them to a bread or muffin recipe in place of half the normal amount of wheat flour.

References: Audubon Field Guide to North American Trees – Eastern Region, Elbert L. Little; Field Guide to Native Oak Species of Eastern North America, J. Stein, D. Binion and R. Acclavatti; Wild Vegetarian Cookbook, Steve Brill; Northeast Area US Forest Service at

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