If you live near, almost in the shadow of, a centuries-old oak, most particularly a pedunculate oak, with its long, long branches which seem to defy gravity, you expect most years a modest crop of acorns: either to grow on for yourself or to give to friends. For the first time in 40 years, this particular tree has given not one single acorn. It was covered with an unusual amount of flowering at the appropriate time, but then came frost after frost. Sympathisers pointed out that it could be a good thing in a way for an old tree - give it a rest from producing its fruit. A year's breathing space.
Now, with all the leaves off and not a single acorn on the ground or from the branches, it is clear that something else has taken over. For the bare branches and twigs are festooned with galls, marble galls, round and brown, not by the hundred but by the thousand. Many of them already showing a neat circular hole to indicate that it may be the grub has escaped and is now perhaps dug into the soil and becoming a chrysalis and then a fly. You will often have read, even here, that the oak tolerates and even provides life substance to several hundred kinds of insect, but this has gone too far. It is not an oakapple; it was, according to Ralph Whitlock in The Oak, introduced to Britain about the year 1834 and spread to us. They were brought in, says the same Whitlock, for dye-manufacturing. Another source implied that scientists started looking for commercial possibilities after they had become well established. They have not, it is said, seriously damaged England's oak woods anyway.
Here is a recipe for gall ink. "To one gallon of water add nine ounces of oak galls and half an ounce of cloves and boil for half an hour; then add two and a half ounces of ferrous sulphate and leave to stand for a month; bring to boil and add one and a quarter ounces of blue-black; mix well and strain off through fine muslin." You wonder, as you read, if the last line isn't going to be - "and then pour it all away." Meanwhile thousands of marble galls cluster on this ancient tree. What do do?
Some years ago, an expert gave an opinion on another sort of gall wasp, cheeringly saying that "only the females go to ground in winter and have to run the gauntlets of bad weather and insectivorous birds. Gall wasps are an interesting study". Indeed.