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OC&R 2025 Appeal
The IOS has launched the 2025 Appeal for the Oak Conservation and Research Fund
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Species Spotlight: Quercus castaneifolia C.A.Mey
Parisa Panahi, Mehdi Pourhashemi, and John Anderson shine a light on this rare oak from the Caucasus
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"Oak: from Seed to Ancient Tree"
Steve Potter reviews Beth Moon's new book
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Donate to Conserve Oaks!
In response to the overwhelming support of oak research and conservation expressed by our members, the IOS launched its Oak Conservation and Research Fund
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Join the IOS today!

Since 1992 the International Oak Society has been bringing together oak enthusiasts from around the world. Born from a shared desire to exchange Quercus seed, the IOS has grown in many directions. Our mission: to further the study, sustainable management, preservation, appreciation and dissemination of knowledge about the genus Quercus and its ecosystems.

To join the IOS, you first need to subscribe to The Cupule, our free e-bulletin, by clicking on the button below. Then log in using the username and password you created and you will find instructions to join the IOS on the home page.

To read about membership rates and benefits, click on "Learn More" below.

Subscribe to our free e-bulletin

Editor's Picks

Yoko and John planting acorns

"Japanese oaks" planted at Coventry Cathedral

Steve Potter | Dec 21, 2025

Group with Quercus macdougallii

Post-Conference Tour: Oaxaca

Six days exploring Oaxaca’s oak diversity, as reported by...

Wally Wilkins | Dec 10, 2025

One of the first planted circles on Hampton Common, London, in partnership with Orleans House Gallery 2025. © Studio Ackroyd & Harvey

Virtuous Circles: Oaks and the Art of Ackroyd & Harvey

Oaks planted in circles as a continuation of the artwork...

Steve Potter | Dec 10, 2025

Plant Focus

Champion Quercus castaneifolia in Iran

Species Spotlight: Quercus castaneifolia C.A.Mey

Chestnut-leaf oak in habitat and in cultivation

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Latest Articles

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Dave Muffly

In Memoriam: David J. Muffly (1965–2025)

A California Master Arborist and oak expert extraordinaire.

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James Harris with fellow Tour participant Bonnie Berckes on the second Post-Conference Tour in 2018 © Charles Snyers

In Memoriam: James Harris (1933–2025)

The IOS received the sad news that longtime member James Harris died on 29 September 2025.

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Group photo at Xalapa BG

Pre-Conference Tour: Morelia, Guanajuato, Puebla, and Veracruz

From Morelia to Oaxaca in the lead-up to the Conference

Latest Blog Posts

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Silent Auction in Oaxaca

Oaxaca Silent Auction Results

Over U$S 2,000 raised for student scholarships

Prof. Chen with the Special Service Award

Prof. Yueh-Fong Chen Thanks IOS for Special Service Award

After receiving his Special Service Award from the IOS, Prof.

Driven Round the Bend by Bender's Oak at Kew

Steve Potter recounts a frustrated yet rewarding hunt for the hybrid

Silent auction at Las Cruces

Fourth Triennial Silent Auction: Items Needed

Support the IOS by donating items for the Silent Auction.

Quercus xmunzii

The X-Files: the Mystery of Quercus ×munzii

A highly entertaining podcast focusing on a rare Californian oak hybrid.

Upcoming Events

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UK Oak Open Days 2026

Sat, 2026-05-16 to Sun, 2026-05-17

The 2026 edition of the UK OODs will feature visits to two oak collections in southeastern England.

Tour of Türkiye

Mon, 2026-09-21 to Mon, 2026-09-28

7-day journey through some of Türkiye’s diverse ecoregions

Tour of Southeast USA

Thu, 2026-10-15 to Thu, 2026-10-22

The Tour will focus on Georgia and Alabama, with incursions into South Carolina and northern Florida.

The International Oak Society acknowledges the generous support of the following institutions:

Supporting Institutional Members

Standard Institutional Members

Rice University

The International Oak Society acknowledges the generous support of the following institutions:

Supporting Institutional Members

Standard Institutional Members

Rice University

Featured link

Trees & Shrubs Online

Trees and Shrubs Online is a truly modern reference to temperate trees and shrubs. Currently there are articles for some 730 genera and 4,500 species, including many subspecies, forms and cultivars.