Tree Notes is about trees -- especially native trees, trees for wildlife, and trees in history.

Saturday, June 6, 2009

Oak galls: Old-time source of ink

Gall-iron ink once used widely

Today, I waited in a parking lot for my daughter to come out from her workplace. I noticed that every pin oak around the building was afflicted with galls. Galls are lumps that form on tree branches when the larvae of insects invade. It is thought that the insects emit a chemical that reacts with the tree's natural growth hormones and growth is grossly overstimulated in the area.

If I had cut a gall open, I probably would have found some of the larvae of the invading insect. If it is the horned oak gall wasp, the number of larvae inside the gall might have ranged from 1 to 160, depending on the size of the gall (Source: Biology and management of the horned oak gall wasp on pin oak.)

The galls usually don't kill pin oaks, but they can cause the branches to die back. I observed this condition on several of the pin oaks around the parking lot. And even if the tree doesn't die, it's greatly disfigured. See the image of a gall-laden tree at this post: Galls on a young pin oak tree.

In the book American Forest Trees (published by Hardwood Record, Chicago, 1913, pp.303-304),  Henry H. Gibson records an interesting historic fact about galls in a chapter about pin oaks:

Oak apples or galls are the round excrescences formed on the limbs by gallflies and their eggs. They seem particularly fond of this species and specimens are often seen which are literally covered with them. The worms which live inside seem to flourish particularly well on the food they imbibe from pin oak.

The primitive school teachers three or four generations ago turned these oak galls to account. They are rich in tannin and were employed in manufacturing the local ink supply. The teachers were the ink makers as well as the pen cutters when the pens were whittled from quills

The process of making the ink was simple. The galls were soaked in a kettle of water and nails. The iron acted on the tannin and produced the desired blackness, but if special luster was desired, it was furnished by adding the fruit of the wild green brier Smilax rotundifolia which grew abundantly in the woods. It was well that steel pens were not then in use for the schoolmaster's oak ink would have eaten up such a pen in a single day.

Galls on a young pin oak
Galls on a young pin oak
(Seen in March)

I was quite fascinated to learn that the U.S. Constitution is written with iron gall ink as well as many other documents written by the founding fathers. In fact, iron-gall ink was widely used for centuries.

Iron-gall ink was the primary writing ink used from 12th through the 19th centuries in the Western world. Popular with artists, architects and mapmakers, iron-gall ink is found in abundance in paper-based collections at the Library of Congress.

The tannin in these inks seems to hold up well, but the iron is a problem for conservationists because it wants to corrode.

I doubt that oak galls have been put to a useful purpose since the days they were used for ink-making!

1 comments -- please add yours:

Stephen West said...

I put a single oak gall in a bowl of water let it soften and crushed it added a couple of iron weights for a weighink machine and the whole has gone adeep black in a coupleof days. Next I'll let it evaporate a bit and I plan to mix it with gum arabic to make an ink. As a draughsperson I am keen to manufacture my own drawing ink from this ancient mathod, also used for the inks on the medeaval Mappa Mundi in Hereford Cathedral.
Stephen at Dolpebyll

Click any label...

advice (45) alder trees (1) Arbor Day (1) ash trees (11) Atlantic white cedar (1) atmosphere (2) autumn (1) bald cypress trees (8) bark (8) bayberry trees (1) beech trees (8) big trees (11) birch trees (2) black cherry trees (1) black locust trees (2) black walnut trees (7) Bradford pear trees (2) buckeye trees (2) butternut trees (1) catalpa trees (4) cherry trees (2) chestnut trees (1) Christmas trees (1) copyright (1) corkwood (1) crabapple trees (1) dogwood trees (6) drought (2) Eastern redbud trees (5) Eastern redcedar (5) ecosystem (6) education (5) elm trees (4) emerald ash borer (11) Empress tree (2) fast growing trees (7) festivals and carnivals (2) fir trees (1) firewood (6) foliage (11) forest (14) forest fires (1) forestry (7) freebies (2) ginkgo trees (1) hackberry trees (4) hawthorn trees (3) hemlock trees (1) hickory trees (11) historic trees (9) history (42) holly trees (1) honeylocust trees (2) hophornbean trees (1) hoptree (1) hornbeam trees (2) internet (3) invasive (13) juniper trees (5) Kentucky coffeetree (2) landscaping (3) larch trees (1) linden trees (1) logging (4) maple trees (10) mimosa trees (3) mistakes (14) narrow trees (1) native fruit (9) native trees (16) oak trees (38) old growth forests (5) ornamental trees (6) osage orange (5) pawpaw trees (1) pecan trees (1) persimmon tree (3) pine trees (9) poems (5) poison-sumac (1) poplar trees (10) prehistoric trees (3) quizzes etc. (1) rhododendron trees (1) sassafras trees (3) serviceberry trees (2) Silver maple trees (2) small trees (4) spring (7) spruce trees (4) statistics (2) sumac trees (4) sweetgum trees (4) sycamore trees (10) tall trees (5) tree cavities (1) tree identification (8) Tree of heaven (2) tree planting (11) tree problems (40) tree removal (2) tree roots (5) trees for problem spots (7) tuliptrees (tulip poplar) (2) urban forest (7) viburnum trees (1) wetlands (5) wild plum trees (4) wildlife trees (27) willow trees (6) witchhazel trees (1) woodworking (2) yellowwood trees (1) yew trees (1)

Enrich your life with the study of trees.

"The power to recognize trees at a glance without examining their leaves or flowers or fruit as they are seen, for example, from the car-window during a railroad journey, can only be acquired by studying them as they grow under all possible conditions over wide areas of territory. Such an attainment may not have much practical value, but once acquired it gives to the possessor a good deal of pleasure which is denied to less fortunate travelers."

Charles Sprague Sargent (1841-1927)

Print references I frequently consult

Benvie, Sam. Encyclopedia of North American Trees. Buffalo, NY: Firefly, 2000.

Brockman, C. Frank. Trees of North America: A Guide to Field Identification. Ed. Herbert S. Zim. New York: Golden, 1986.

Cliburn, Jerry, and Ginny Clomps. A Key to Missouri Trees in Winter: An Identification Guide. Conservation Commission of the State of Missouri, 1980.

Collingwood, G. H., Warren David Brush, and Devereux Butcher. Knowing Your Trees. Washington: American Forestry Association, 1978.

Dirr, Michael. Dirr's Hardy Trees and Shrubs: an Illustrated Encyclopedia. Portland, Or.: Timber, 1997.

Elias, Thomas S. The Complete Trees of North America; Field Guide and Natural History. New York: Book Division, Times Mirror Magazines, 1980.

Grimm, William Carey. The Book of Trees;. Harrisburg, PA: Stackpole, 1962.

Hightshoe, Gary L. Native Trees, Shrubs, and Vines for Urban and Rural America: a Planting Design Manual for Environmental Designers. New York: Van Nostrand Reinhold, 1988.

Little, Elbert L. National Audubon Society Field Guide to North American Trees. New York: Chanticleer, 1996.

Martin, Alexander C., Herbert S. Zim, and Arnold L. Nelson. American Wildlife and Plants. New York: McGraw Hill, 1951.

Mitchell, Alan F., and David More. The Trees of North America. New York, NY: Facts On File Publications, 1987.

Randall, Charles E. Enjoying Our Trees. Washington: American Forestry Association, 1969.

Settergren, Carl D., and R. E. McDermott. Trees of Missouri. Columbia: University Extension, 1995.

Sternberg, Guy, and James W. Wilson. Native Trees for North American Landscapes: from the Atlantic to the Rockies. Portland: Timber, 2004.

Wharton, Mary E., and Roger W. Barbour. Trees and Shrubs of Kentucky. Lexington: University of Kentucky, 1973.

Wyman, Donald. Trees for American Gardens. New York: Macmillan, 1965.

Photos and text copyright © 2006-2010 by Genevieve L. Netz. All rights reserved. Do not republish without written permission. My e-mail address is