Chris Gilchrist
This year where I live in South Devon a lot of oaks have oak acorn galls. These are caused by a wasp, Andricus quercuscalicis, which lays its eggs in the developing acorn which then deforms. The wasp grub eventually eats its way out leaving a small hole. Are these in evidence at Greenstreete?
Maybe this has happened because the oaks also seem to have a lot more acorns this year. Is it a mast year for acorns? ” A mast year is a term used in ecology to describe a year in which trees or other plants produce a large number of seeds or fruits, much more than in typical years. These years usually occur irregularly, every few years, and are followed by years with much lower seed production.” It’s a trick often used in nature: overwhelm your predators with abundance.
When oak trees produce lots more acorns, jays – which bury acorns and retrieve them to eat in winter – bury more than their usual tally: up to 7,000 of them. This excess means that despite having good memories, the birds forget where they’ve put many of them… so there’s a bigger crop of new oak saplings the following year.
(Ed: Here is more info on the different types of Oak gall – https://www.rhs.org.uk/biodiversity/oak-gall-wasps )
Greenstreete Oaks:
Ed: Here is info on mast years:
“Mast years are not just one off events for individual trees. The vast majority of trees in a particular species will have a fantastic crop all across the UK in the same year. How the trees co-ordinate this when they’re so far apart is one of nature’s many mysteries.
https://www.woodlandtrust.org.uk/blog/2020/10/what-is-a-mast-year/
We don’t yet know exactly how trees communicate with each other and we can’t predict when any one species will have a mast year, but we do better understand what causes it. Weather certainly has a part to play.”
Thanks, Chris. Certainly noticed a glut of acorns recently on the trees around the Field Hut. Didn’t notice any galls but wasn’t looking for them.