Oaks on the Prairies

Oaks on the Prairies, Post by Deborah Naslund, Photos as attributed.

Deb Naslund is one of the long time volunteers on the prairies and has been very active in Prairie Appreciation Day since she started volunteering.  She is also extremely active in the Washington Native Plant Society.

Oaks on the Prairies

Everyone has a favorite station at Prairie Appreciation Day. One of my favorites is “Oaks on the Prairies” a.k.a. the “Oak Gall Ink Station”. I’ve enjoyed staffing this station for several years. I love to see young and old alike try their hand at writing and drawing with the oak gall ink while learning more about oaks.

Why do we talk about oaks at a celebration of prairies? Oak woodlands are often associated with Puget Sound Prairies, thriving on the same glacial outwash soils. Quercus garryana, commonly called Oregon white oak or Garry oak, is our only native oak in Washington. Just like many prairie species, it is well adapted to gravelly dry soils and frequent, low intensity fires. As a Garry oak ages, its bark thickens, making the trees more fire resistant than the conifers that may be invading their stands. Garry oaks also have the ability to vigorously sprout from the root crown if the tree is severely damaged. You can find these stately oaks, some perhaps over 300 years old, growing in association with a species-rich community of native grasses and wildflowers.


Garry Oaks, Photo by Deb Naslund

Sadly, these lovely woodlands are disappearing from the landscape due to land development and Douglas fir encroachment among other threats. They are ranked as “Critically Imperiled” by the Washington Natural Heritage Program (https://www.dnr.wa.gov/publications/amp_nh_conservation_status.pdf ). But there are many efforts underway to restore and protect these threatened ecosystems. For more information and to learn how you can help, visit http://www.southsoundprairies.org/. For a deep dive into the science of prairie-oak conservation and species recovery efforts in our area, see: https://cascadiaprairieoak.org/


What are oak galls? You can often find Garry oaks that are harboring what look like round, pithy balls on their twigs or leaves. These are oak galls. The tree grows a gall in response to the larvae of several different species of oak gall wasps. One of the main wasps on Garry oaks is the California oak gall wasp (Andricus californicus), which forms large, persistent, apple-like galls on twigs. The galls develop when the wasp pierces the tree’s flesh and lays its eggs. Growing the gall doesn’t hurt the tree, but does provide a home for the wasp larvae.

The galls are green when they form, but once the wasp larvae mature and leave, the galls dry up and turn brown. You can often find oak galls on the ground around mature oak trees. Look under oaks in your neighborhood or in a local park.


Oak Gall

What is oak gall ink? Oak gall ink has been used for centuries. It uses the chemical reaction between the tannic acid in the oak gall and iron oxide, from a rusty nail or other source, to produce a black pigment. Adding a binder, such as gum arabic, creates an ink that can be used with quill, reed or steel dipped pens. The permanence and water-resistance of this type of ink made it the standard writing ink in Europe for over 1,400 years. The Declaration of Independence, Magna Carta and other important documents were written using gall ink. Also, according to recent research, traces of gall ink have been found on the Dead Sea scrolls.

You can make oak gall ink at home with those oak galls you found on the ground. Here’s the recipe:

Oak Gall Ink Recipe

  1. Put ½ cup of crushed oak galls in a glass jar, add a cup of water and let the mixture sit for a week or two or even a month.
  2. Add a few steel nails (not galvanized) to the mixture and let sit for another week or two. Old rusty nails work best.
  3. After a good, dense ink has developed, filter off the oak galls. The nails can be left in to add further density.
  4. Add one tablespoon of gum arabic (available at art or craft stores) to thicken the ink.
  5. When used, the ink writes in gray, but becomes black when it has dried.

Give it a try and see what you can create. Note that this ink works with dip pens; it is not suitable for fountain pens. And, be careful as this ink was prized for its permanence!

Poster created with oak gall ink by participants to Prairie Appreciation Day 2019.  Photo by Dennis Plank

Poster created with oak gall ink by participants to Prairie Appreciation Day 2019. Photo by Dennis Plank