Rachel Rose: Modern day plant hunters on the trail of historic oaks

Oak hunters confer at Whanganui's James McGregor arboretum - Hamish Randle, botanist Kathryn Hurr and Eric Cairns of the Oak Interest Group.

Late last autumn I followed Ian Moore up the farm road to his established wetlands and what a wonder they were.

The pin oaks were flames of colour on a dark, brooding day, punctuating the more muted tones of the ti kouka and harekeke. The water was still and dark.

I loved Ian's choice of plants — the mix of both native and exotic species that he'd chosen for function as well as form. The pin oaks, for example, produce nutritious food for ducks who can swallow the tiny acorns whole.

Those oaks captured my imagination and perhaps that's where my fascination with these ancient trees began.

In late spring, I trailed along behind a couple of oak enthusiasts as they bounded about the oak arboretum in Cambridge, talking excitedly to each other in what sounded like Latin, noting various botanical details and pondering the parentage of these 20-year old oaks.

We met Eric and Annette Cairns first through the Tree Crops Association — or perhaps NZ Farm Forestry Association (NZFFA), I forget which came first. They are active in both organisations and are a wealth of knowledge.

We met botanist Kathryn Hurr that day in the Bay of Plenty; much younger than the Cairnses, she is their equal in enthusiasm and impressively knowledgeable. She's not long back from a trip to the United States to the 9th International Oak Society Conference.
It was pleasure to host these three in Whanganui earlier this month and show them some of the oak trees of our district.

Eric and Kathryn have founded an Oak Interest Group, which will probably find some official standing with NZFFA but, for now, exists as a lively and learned discussion on Facebook.

Once upon a time, plant collectors swapped acorns or gathered them on overseas planting hunting trips, but those days are long gone.

Fortunately, diseases ravaging oaks in northern hemispheres have not reached our shores and we all want to keep it that way. The cost of bringing in acorns in compliance with Ministry for Primary Industries quarantine is prohibitively expensive.
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There are many remarkable things about oaks, and one of them is their incredible diversity and distribution.

Rachel Rose

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So Eric and Kathryn and a growing group of other appreciators of oaks are locating and documenting existing oaks around New Zealand. What species do we already have in the country? Where are the best specimens? With this knowledge, the best of what we have might be propagated.

There are many remarkable things about oaks, and one of them is their incredible diversity and distribution.

There are oaks native to Asia, Europe and North America; their native range just dips into the southern hemisphere in the places like Indonesia. And, of course, they were introduced to many more far-flung locations, such as New Zealand, and happily made their home here.

Oaks thrive because of their adaptability. Oaks' native range stretches from Kyoto to Kashmir; from Jerusalem to Istanbul; from Moscow to Mexico City.

In that arboretum in Cambridge, I began to understand something of the diversity of their appearance also.

I met trees I never would have believed were oaks. Q. fastigata — that's an oak tree? Neither the shape of its leaf or its columnar form bear any resemblance to that of, say, Q. robur, the English oak common in Whanganui and much of the rest of the country.

Oaks hybridise readily and, to make identification even more challenging, there is a lot of variation — in the shape of leaves or size, shape and taste of acorns for instance — even within a single species.

My botanical education continued with the visit from my new friends. I'd done some preparation, consulting the register of notable trees and quizzing Whanganui District Council's very helpful arborist Claire Lilley.

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Acorn flour from holm oak, laboriously processed by Kathryn Hurr and milled in a coffee grinder. Photo / Kathryn Hurr

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We started with the oaks planted early last century in the arboretum on Anzac Parade by plant collector and learned horticulturist James McGregor. There's greater diversity there than we had realised.

Our next stop was the farm he established in Fordell, which has many old and interesting trees.

Too many trees, too little time ... We just managed a visit to Fordell township, to the Q. ilex that spreads over the carpark at Fordell preschool. It's on the Notable Tree Register and is, indeed, an impressive tree (all the more for surviving having its roots buried under the impermeable car park surface).
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We're hoping that Chronicle readers can shed some light on the origins and history of this beautiful tree.

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But then something else caught Eric's eye ... There, in the far corner of the preschool grounds, just outside the entrance to the Fordell School, is a very unusual oak. It has notably large leaves and there is evidence its acorns are also giant. It's possibly Q. dendata, a Japanese Emperor Oak.

Myself, I wonder if James McGregor might have had something to do with it, given its age and proximity to his homestead. We're hoping that Chronicle readers can shed some light on the origins and history of this beautiful tree.

And we would love to hear about any oaks in the district that may be notable for their age, variety or characteristics.

Kathryn, in particular, wants to know about individual trees most popular with rats and other critters. Their favourite acorns are likely to be sweet ones with less tannin that will be pleasing to human palates also. I've tasted Kathryn's acorn flour bread and it's a tasty and satisfying loaf.

*Rachel Rose is a Whanganui-based writer — more info (and links to the Oak Interest Group, Tree Crops Association and NZFFA) at www.facebook.com/rachelrose.writer