Tree of the month: Rowan

A few nights ago the moon was new. So according to this version of the Ogham ‘tree calendar’ extended into 2013, we’re now in the Month of the Rowan. You might choose to follow my ‘ogham’ tag for other posts in this series.

The ancient Celts used their Ogham alphabet for various purposes but they don’t seem to have associated a calendar with it. That use of the Ogham is a 19th century invention! I like this calendar, though. It directs attention to a different species for each lunar month. So today, let’s admire the rowan.

The rowan or mountain ash (Sorbus aucuparia) is native to Britain. It’s distinctive for having compound leaves. Those look a bit like the leaves of the common ash (Fraxinus excelsior) but they’re not the same tree. They’re not even in the same genus.

Because these tree species aren’t closely related, S. aucuparia doesn’t get the dreaded dieback disease (Chalara fraxinea) which is spreading in British populations of F. excelsior. We might be going to see a Britain in which you can tell whether you’re looking at a mountain ash or a common ash by whether it’s dead.

Meanwhile, you can tell apart these two species because the mountain ash is a smaller tree, its leaves are smaller, their edges are serrated and its bark has horizontal stripes. You could also look at where the tree grows. Mountain ash is a pioneer species colonising land where most other woody plants don’t take root. It’s even found high on British mountains, hence its name.

If you’re looking in autumn or winter, you’ll find red or orange rowanberries which are one of the great beauties of the mountain ash. They’re food for wild birds. The birds which eat most rowanberries are the widespread mistle thrush (Turdus viscivorus), the declining song thrush (Turdus philomelos), and two of our winter visitors, the redwing (Turdus iliacus) and the fieldfare (Turdus pilaris). If you pause on one of the bird pages I’ve just linked to, you’ll see a photograph of that species tucking into rowanberries. This arrangement suits the rowan tree just fine because the bird distributes seed in its droppings. (Cue puerile remarks about Turdus turds.) In fact, seed distribution is why rowans make berries.

Do rowans make berries for us, too? Yes, but don’t eat them raw. When raw, if you’re not a bird rowanberries can upset your stomach or damage your liver. Instead you can make them into jelly or sauce to serve with red meat, or into wine. In fact, there have been reports of birds ‘getting drunk’ on rowanberries. I’m grateful to my fellow blogger narhvalur for drawing attention to those tipsy birds.

Ahem. I’ll now stop lowering the tone of this blog post. Instead, I’d like to show you how the Royal Forestry Society celebrates the rowan. This hardy little tree provides food and habitat for moths, pollinating insects and lichens, as well as for all those birds. And it’s so pretty, isn’t it?


About argylesock

I wrote a PhD about veterinary parasitology so that's the starting point for this blog. But I'm now branching out into other areas of biology and into popular science writing. I'll write here about science that happens in landscapes, particularly farmland, and about science involving interspecific interactions. Datasets and statistics get my attention. Exactly where this blog will lead? That's a journey that I'm on and I hope you'll come with me.
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9 Responses to Tree of the month: Rowan

  1. Rachel says:

    Just another one of my random little comments – rowan also used to be sacred a few centuries ago, because people believed that planted next to or in graveyards, rowan could keep the dead at peace….

  2. manuelinor says:

    lovely! the Rowan is my ‘birth’ tree, so thank you for the great information on it! I hope I’m lucky enough to see one in the flesh one day 🙂

    • argylesock says:

      I hope you will, too. Isn’t it funny how a species which seems commonplace to one person, is exotic to another? I still have my mother’s recipe books from the 1950s in which there’s solemn discussion of ‘tinned Australian meats’ such as kangaroo.

      • manuelinor says:

        yuk – kangaroo meat isn’t that great fresh, let alone tinned! 🙂

        • argylesock says:

          Good thing I never tried the tinned kanga, then! In fact I don’t know whether it still exists. The only time I ate kangaroo it was a steak in a restaurant – one of those ‘try a novel culture’ type places, the novel culture being Aussie. The steak was stingily small and it tasted all right, but I wasn’t desperate to eat another.

          I suppose this restaurant might have looked, to you, the way ‘English style pubs’ in America look to me. Bloody ridiculous. And don’t get me started on the American ‘English muffin’! When I was in Australia (only for a few days) I didn’t notice any daft ‘English’ themed stuff, so that was a relief.

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