Is mistletoe good, bad, or somewhere inbetween?

New Scientist’s Christmas Issue 2012 – that’s mistletoe (true Viscum album) hanging from the masthead.

Picked up a copy of the Christmas New Scientist  yesterday and was pleased to find a two page feature on mistletoe, with headline features claiming it to be ‘misunderstood’, ‘marvellous’ and the ‘unsung hero of the woods’. What had prompted this lavishing of praise for Viscum album? (and why woods – that’s not a Viscum album habitat?).

The answer, of course, is that the article wasn’t about Viscum album, the Christmas mistletoe, at all – indeed V. album was barely mentioned. This was an article about mistletoes, plural, so those headlines (including the cover) about mistletoe, singular, were a little misleading.

The article was based entirely on David Watson’s recent research in New South Wales, Australia, where he has been demonstrating mistletoes’ (note plural) contribution to forest biodiversity by removing all the mistletoe species in one area and monitoring biodiversity in that area compared to another. Results suggest that the mistletoe makes a significant contribution – directly and indirectly – with 20% less species in the mistletoe-free woodland three years later. Details are available in the formal paper from the Royal Society.

David Watson, whose NSW research says mistletoes are good,  inspecting mistletoe (pic by Magrit Beemster)

If this sounds familiar it’s because you read it here first back in July when I uploaded a short piece called Mistletoe is for Life, not just for Christmas! – my view being that it demonstrated that mistletoe shouldn’t just be thought of at Christmas. The editorial team at New Scientist obviously decided to take a different line – and to sit on the story until Christmas – which is understandable I suppose but a little aseasonal of them.

Scientific American wouldn’t do that would they? Well, yes they would and they have too – in their blog entry last Friday – covering exactly the same issues, also 6 months after the research was reported.

Both magazines talk up the story as newly portraying mistletoes as good not bad. This despite that fact that the concept is old (it’s obvious mistletoes contribute to biodiversity, with many known to have significant inter-relationships with other species – Watson’s research takes the concept a large step forward, but come-on guys, we all knew the basics already). And this despite the fact that mistletoes can be, and often are, in forestry and tree-health terms, very Bad. This isn’t ever a black and white scenario – all mistletoes belong in the grey area of good for some things, bad for others.

Armidale Dumaresq Council senior officer Richard Morsley inspects one of the destructive mistletoes at the Arboretum.
NSW Armidale Dumaresq Council senior officer Richard Morsley inspects one of the destructive mistletoes at the local Arboretum.  Spot the difference between this mistletoe pic and the one with David Watson above right…

As an example of the opposite scenario consider a another recent mistletoe story, also from New South Wales, where Armidale Dumaresq Council are contemplating yet another round of mistletoe control in Drummond Park and their Arboretum as many trees are becoming infested by too much mistletoe, causing some to die prematurely.

This is the reality of mistletoe – good in moderation but bad in excess. And ironically it may be man-made habitats that encourage the excess. Most mistletoes tends to grow luxuriantly on trees in open situations – parks and arboreta are perfect conditions for excess growths – hence the problems in Armidale.

The Mistletoe League Project is collating information on mistletoe management in Britain

And that’s also, probably, one of the reasons for some of the problems of excess mistletoe growth here in Britain, where THE mistletoe, Viscum album, is becoming a problem in older, neglected, orchards as well as in some garden situations.  Our mistletoe can become dominant on trees in the open habitats of orchards and gardens and lack of management will lead to overgrowth and tree death.

If you have mistletoe in these situations do take part in the Mistletoe League survey project, collecting information about mistletoe management on fruit trees in the UK.