Yesterday I spent the whole day in Harrogate helping run an OPAL / Yorkshire Naturalists Union course about how to put biological recods into Excel. Those of us new to biological recording went outside in the sunshine to do some species recording. Despite it being cold and damp, we saw lots of wildlife - the highlights were a nuthatch and this amazing gall...
Note Adrian Norris standing underneath the tree to give you an idea of scale!! The other interesting thing about this gall was that grey squirrels are now using it as a drey, we saw one poke it's head out of the top!
The British Plant Gall Society website says that galls are abnormal growths produced "under the influence of another organism". Organisms that can cause galls to grow include certain types of fungi, aphids, mites, some species of flies, viruses and bacertia. Unfortunately we couldn't identify the tree, which is one way of trying to identify what may have caused the gall, but one of the course attendees specialises in plant galls and he suggested that this one might be caused by a bacteria.
My friend Ellie just came in and asked if the galls damage the tree, I said they probably didn't, can anyone confirm this??