Oak Tree in Cherry Tree Wood
Dear Readers, there is an on-going arms race between plants and the creatures that eat them, that can involve everything from camouflage to chemical weaponry. However, scientists in at the University of Würzberg in Germany have discovered that oak trees that are badly infested with caterpillars in one year will delay opening their leaves by three days during the following year.
Caterpillar eggs are usually laid so that their hatching coincides with the newest, greenest leaves appearing – these are the most nutritious, and the easiest for those little jaws to munch. The scientists did an aerial survey of oak forests in 2019, during which time there was a dramatic infestation of gypsy moths, which caused extensive damage to many of the trees. It was found that the trees who had suffered the most drastically were the ones who delayed producing their leaves by three days in the following year, meaning that any caterpillars that hatched on them starved. This reduced leaf damage by some 55 percent.
While scientists agree that there’s a correlation between leaf opening time and caterpillar predation, it still hasn’t been proved that one causes the other – it could be that the delay is the result of the tree being weakened, rather than a precaution against future leaf loss. But it’s certainly intriguing, and I look forward to future studies revealing more.
You can read the New Scientist article here.
The journal article is here.
Not necessarily relevant, but I thought you might be interested…
We have a huge oak tree just over the fence, in a neighbour’s field, at the far corner of our garden. Before strimming and cutting our overgrown grass next to our sheds, I must have pulled up around 50 tiny oak trees, many still attached to their acorn. After all, that many trees in such a small area would never survive and anyway how would I get into the sheds? And what does one do with 50 tiny oak trees? I’d love to replant them somewhere, but where?
But the more interesting thing is that this morning we had 3 Tawny owlets together with one of the parents resting in that tree. We’ve seen and heard them for the past 3 or 4 days, They’re old enough to fly from tree to tree, so I’m thinking they might be around 8 or 9 weeks old.
And my wife heard lots of cheeping in the same area and she thinks there could be a woodpecker nest somewhere close by…
Oak trees really go for it, don’t they, especially as most of the young trees will be in the shadow of their parent and so won’t thrive. But the owl news is really exciting. We’ve had one brood of great tits, and now they’re building a second nest. Must be a good year for the birds.