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University of Iowa Center for the Book fosters annual kozo tree harvest for Japanese-style paper
Rare effort supports literary conservation, art from Coralville plot
Nov. 30, 2025 5:30 am
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CORALVILLE — As dozens of volunteers convened this month for the annual kozo tree harvest, the effort was another one for the books.
It was also one for the art projects, the education, the preservation of tradition, and a formation that, for at least a day, transformed a motley crew — students, university faculty, paper makers, and people who simply think it’s cool — into a community.
Every fall, from a small plot no bigger than an average garden, the University of Iowa’s Center for the Book (UICB) hosts one of only two such efforts by universities in the country.
Here’s how the annual harvest transforms mulberry hybrid branches from Japan into a niche type of paper that’s used to repair the U.S. Constitution, maintain historical artifacts at the Louvre Museum, and create new pieces of art in Iowa.
How it started
About 30 years ago, current UICB Professor Emeritus Timothy Barrett started the garden with kozo plants sent by mail from Japan, where the former Fulbright fellow studied papermaking for two years.
From a facility that once processed laundry for a tuberculosis sanitorium, the Japanese craft has continued in the heartland for generations at the University of Iowa Research Park.
In 2020, adjunct assistant professor Nick Cladis, who primarily teaches papermaking courses for UICB, came in to revive a program that had started to wane.
Since then, the effort has blossomed into a kozo yield of about 30 kilograms each year — double what it was when he started. One kilogram of the delicate bark just beneath the surface of each branch produces about 80 to 100 sheets of paper measuring two by three feet.
What has also grown is the number of volunteers. In 2020, Cladis had about 10 volunteers; the year after, he had only three.
This harvest, he had dozens. Students, faculty, international scholars, interested friends and even their children collected all the branches in less than two hours on Nov. 14. Volunteers and leaders said it’s the sense of community that compels them to pitch in.
“It slows us down, that’s the primary thing. To come out and get your hands dirty, smell fresh air, be around people and do something that’s so connected to where you are making your work is really important,” Cladis said. “The tradition … can inform the way you live your life, too.”
He said the production, which is as educational as it is practical, preserves ecological connections that are just as important as understanding how food is grown.
“We grow our own food. Why don’t we grow our own art supplies?” he asked. “Contemporary art could benefit a lot from re-finding the charm of that.”
What it’s used for
In Cladis’ classes, paper making has no borders. But in papermaking, there are two dominant paths: Japanese styles and European styles.
The professor studied for 10 years in Echizen, Japan, a city about the size of Iowa City. There, 55 paper mills make just as many types of paper in a place that has specialized in the craft for more than 1,000 years, he said.
“When I was living there, I was amazed by the diversity of paper,” he said. “Paper (in Japan) is like wine in France. Every little village, every prefecture has its own style.”
Washi, the thin paper made from kozo, is apt for preserving delicate historical documents as they age. In 1999, the National Archives commissioned paper made by Barrett for conservation efforts of the U.S. Constitution, the Bill of Rights and the Declaration of Independence.
Other manufacturers in Japan make material specifically for conservation at museums like the Louvre in Paris, said harvest host Jamie Capps, a University of Iowa alum and printmaking instructor at Saint Paul College in Minnesota.
“Paper makers like me depend on having this fiber,” she said.
But Cladis’ approach to the paper has emphasized its use in art and how art can be influenced by a paper’s qualities in both tangible and abstract ways.
“You can make your whole project from a plant grown here, and I think a lot of students were really into that,” he said.
Japanese paper can be thin. For that reason, the paper made here is sold to conservators and libraries across the country for restoration, Capps said.
It can also be incredibly strong thanks to long fibers that give it high tensile strength and resist degradation over time — serving archival paper needs.
Hemicellulose, a thin green layer under each branch’s outer bark, gives paper body. The white bark, laying underneath the green, produces a paper that is soft and delicate.
Shelby Welte, a graduate art student and UICB certificate candidate for book arts, first got involved in production to procure paper for photography art projects, where she can adjust it from translucent to opaque through layering.
She loves the paper for its softness. In Japan, it’s used cushions, candy wrappers and wedding invitations.
“Every time I show someone the material, they think it’s fabric,” she said. “I had no idea there’s even a world of art that is exclusively paper, where paper is the final product — it’s not the vehicle for the product.”
Today, she harvests in part for an experience that transcends engineering while producing a uniquely handcrafted product through sometimes tedious labor.
“It’s an experience you don’t get anywhere else,” she said. “(I) can say I have known this plant since it was a baby.”
How it’s made
Once established, kozo can grow in about six to eight months, with sufficient rainfall. Most branches have a circumference of just a few inches.
Volunteers cut them at an angle to ease processing and regrowth before packaging them into neat bundles tied with twine.
In the nearby building, they’re arranged into an old cauldron employed by the former laundry facility, where they’re steamed for about 30 minutes until the inner pith of the wood starts to pop out of the bark.
Between the pith and the outer black bark, white and green bark offer the keys to washi and Japanese paper.
After steaming, bundles are taken outside, where volunteers can strip the bark in one swoop. Then, they’re returned to the facility, where strips are arranged in bundles and hung to dry on a line.
After drying, a naginata beater cuts the fiber and processes it into pulp. Once drained, paper makers are left with the long fibers that give the paper strength.
The paper production, traditionally a winter vocation for Japanese rice farmers, continues to be a winter activity in Iowa due to temperature and humidity requirements.
Leftover pith wood is repurposed as firewood or for other art projects.
Why it matters
In an age when children seem to have better instincts with an iPad than with art supplies, some facilitators of the harvest are concerned that paper making is a dying art.
Others have a different perspective. Welte, a member of Generation Z, has seen a resurgence of interest in physical media among her students, who express strong ties to it through their everyday work.
Maintaining a volunteer base from diverse backgrounds helps preserve the knowledge imparted through the harvest each fall. Continued engagement translates to interest and vitality not just for paper making, but the overall mission at hand for UICB.
But fading the line between tradition and contemporary practice may play a role in pushing the art form forward.
“I think they inform each other all the time, and it’s a lot more dynamic than we assume,” Cladis said.
In preserving a sacred tradition, the UICB remains a key player in preserving the arts of the past while producing the art of the future.
“Seeing that and experiencing it myself, I feel like I’m a part of something much bigger than I am, and I try to honor that,” Capps said. “Even though I’m not Japanese, I try to honor that tradition.”
Comments: Features reporter Elijah Decious can be reached at (319) 398-8340 or elijah.decious@thegazette.com.
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