Log in

Editor's Picks

Group photos Texas OODs
Five days of oaking in the Lone Star State.
Roderick Cameron | Oct 21, 2023
Tour Participants on Fiddler Peak
An account of the Tour guided by Sean Hogan
Website Editor | Oct 19, 2023
Quercus pacifica
An collection specializing in native Californian oaks
Christina Varnava | Oct 18, 2023

Plant Focus

A small but mature Alabama sandstone oak producing acorns © Patrick Thompson
A Critically Endangered dwarf oak 

IOS Holds Its Inaugural Virtual Event

On August 29 2023, the first IOS virtual event was held in co-organization with the Global Conservation Consortium for Oak using the Zoom platform provided by The Morton Arboretum, hosted by Amy Byrne. The webinar covered two different but equally interesting topics: "Cryopreservation at CREW" and "Oaks at Grigadale".

First, we learned about the state-of-the-art in oak cryopreservation through the presentation by Dr. Valerie Pence (presenter) and Gillian Ross (co-author). Working at the Center for Conservation and Research of Endangered Wildlife at Cincinnati Zoo & Botanical Garden, Dr. Pence and her colleagues focus on the cryopreservation of oaks, as this genus cannot be seed banked conventionally. The reason is acorns' loss of viability due to desiccation. Thus, cryopreservation is employed as an alternative ex-situ conservation approach. In a nutshell, cryopreservation is the storage of living tissue in liquid nitrogen for future recovery and growth as plants. Oaks can be cryopreserved by means of embryo axes, somatic embryos, shoot tips, pollen, and potentially dormant buds.

Screenshot from Dr. Valerie Pence's pesentation
Screenshot from Dr. Valerie Pence's presentation

Before the IOS grant, the group started with Quercus gambelii, Q. hinckleyi, Q. suber, and Q. virginiana, using new growth from mature trees or seedlings for their shoot-tip samples. After the IOS grant, they increased the collection substantially thanks to Max Winkeljohn who acquired a lot of material (and probably some thanks to this webinar as he asked the participants for acorns). Max is also working on medium improvements, specifically looking at STS (silver thiosulfate) that can help initiate culture growth by inhibiting the stress-induced hormone ethylene. In the presentation, the focus was on Q. virginiana and Q. hinckleyi. Both species can survive in liquid nitrogen, but the use of cryoprotectants (the group uses PVS2) improves survival significantly. This was also shown for Q. suber and Q. gambelii. Gillian Ross also observed cold hardening. The results showed that cold-hardened shoot tips of Q. virginiana can have better survival in liquid nitrogen. Unfortunately, this was not the case with Q. hinckleyi and Q. suber.

Developing protocols for different oak species proved to be a complex and unpredictable task. Still, Dr. Pence’s group has provided valuable results and keeps expanding the number of oak species and factors involved in culture initiation, survival and recovery. The research continues, as the IOS Oak Conservation and Research Grant helped provide opportunities for further funding.

Second, we had a wonderful tour of the Grigadale Arboretum in Argentina by Roderick Cameron, who gave us the most inspiring stories followed by historical and current images and footage. The Arboretum was founded in 1992 by Duncan and Bridget Cameron, Roderick’s parents. Created on a bare field, it covers 15 hectares, 1.5 being a quercetum. An important landmark is a lake formed in a depression close to a homestead that is protected by trees from southerly and southwesterly winds. Although the closest native oak is Q. humboldtii in Colombia, 9,500 km away, the oaks seem to grow pretty well at Grigadale. The quercetum started in 1995 with a focus mainly on oak species, but also hybrids and cultivars. Today the collection contains over 100 taxa. They come mostly from European and UK nurseries and of course IOS Seed Exchanges. The first oaks were planted at 6–7 m apart. As such density demanded thinning only a few decades later, the distance between the trees was later expanded to 10 m. Other challenges include occasional flooding and drought. Ants, hares, parrots and especially the notorious borer known as bicho taladro in Spanish (Megaplatypus mutatus) are also the problems encountered in maintaining the collection. Although the origin of some of the trees is unknown, the database is modernized and connected to a website (www.grigadale.org) containing a catalog of trees, measurements, images, and a map. Some highlights from the Arboretum were presented in the second half of the presentation—first the Mexican oaks—such as beautiful Q. rugosa and Q. rysophylla. Later on, equally stunning in their own way, the US oaks: Q. texana (survivor of floods in the Arboretum), Q. arkansana, Q. oglethorpensis, and Q. minima. Then, from Asia, Q. leucotrichophora, Q. semecarpifolia, and the largest known Q. baloot in cultivation. From Europe, a beautiful Q. robur ’Concordia’ that unfortunately died in 2016, but was dedicated to the Golden Jubilee of Elizabeth II. A reply from Buckingham Palace to Bridget’s letter holds the memory of this tree. Then Q. robur ’Argenteomarginata’, Q. dentata ’Pinnatifida’, Q. cerris ’Curly Head’, and then hybrids Quercus ×warburgii and Q ×vilmoriniana.

Screenshot from Roderick Cameron's presentation
Screenshot from Roderick Cameron's presentation


As the Arboretum now holds Level 1 accreditation from ArbNet, one of the future directions is adding threatened species to the collection. The presentation was concluded with beautiful aerial footage of the Arboretum.

In the Q/A section, both topics were further discussed through a dozen questions from the participants. Finally, there was feedback from participants regarding topics for future webinars. There was a general agreement that mixing topics is a good approach. Every IOS member who would like to present at some of the future webinars may contact Roderick Cameron or Amy Byrne here.

In conclusion, the first IOS Webinar was a success. Although physical meetings are preferable, webinars proved to be a promising way for IOS members to gather in between other events.

IOS members can find a link to the recording of the webinar here.