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Editor's Picks

Carlos collecting Quercus ×alentejana (Q. faginea × Q. pyrenaica) in northeastern Portugal for his PhD thesis © Carlos Vila-Viçosa
An interview with Portuguese oak conservationist Dr. Carlos...
Amy Byrne | Apr 19, 2024
Roderick Cameron | Apr 13, 2024
Pages from Gert's book
It was a great pleasure for me to be able to write about my...
Gert Fortgens | Feb 15, 2024

Plant Focus

Quercus crassipes acorns with inrolled cupule margin
One of the more well-known Mexican oaks in cultivation.

Advancing the Ex-Situ Conservation of Oaks Using Cryopreservation (2020)

Project Contact: Valerie C. Pence, Ph.D., Director of Plant Research, Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio.

Project Summary: The 500 species of oaks (Quercus spp.) are iconic trees that anchor many of our most precious ecosystems. Of the 91 species of oaks in the US, 30% are of conservation concern due to loss of habitat, disease, and climate change. Conserving oaks in their habitats is crucial, but ex-situ, or off-site, conservation is also necessary to provide insurance against the loss of those species that are endangered in the wild.

Conserving oaks is challenging, because the seeds cannot survive the drying necessary to store them in seed banks. Species with such seeds are known as exceptional species. The Center for Conservation and Research of Endangered Wildlife (CREW) at the Cincinnati Zoo & Botanical Garden has taken a special interest in exceptional plants, including oaks, and specializes in the techniques needed for their conservation.

Oaks can be conserved as trees in botanical gardens, but there are also methods available for storing plant embryos and stem cells in liquid nitrogen. These methods, known as cryopreservation, take up little space and can preserve the tissues for decades, but the use of these methods for conserving oaks is just beginning. This project is directed at applying cryopreservation to endangered oaks and providing training information to assist others in developing similar research projects.

For this project, we will be focusing on stem cell, or shoot tip, cryopreservation. We have demonstrated its feasibility with the critically endangered Quercus hinckleyi. In this project, we will work with three threatened oak species, Q. arkansana, Q. havardii, and Q. acerifolia

Further Reading


OC&R Testimonial


IO 34 cover

  Shoot-Tip Cryopreservation for Oak Conservation
Gillian M. Ross and Valerie C. Pence (International Oaks No. 34)

IO 34 cover

Improving Shoot Survival In Vitro Through Ethylene Inhibition
Max Winkeljohn (International Oaks No. 34)

Webinar Dr. Valeri Pence

Shoot Tip Cryopreservation for Conserving Oak Biodiversity Ex Situ--with Updates
Valerie Pence and Gillian Ross
Presented during IOS Webinar #1 - August 29, 2023 (starting at 3:50 min)