Posted by joan regan on September 4, 2006

Q: In my area, just north of Boston, there seem to be an exceptional number of oak apple galls on the ground. I am sure they are galls. However they are redder and greener than the oak apple galls I'm used to finding in winter. There are literally dozens along the road where I walk.

Along the same walk there seem to be very few acorns or hickory nuts. Last year was a light acorn year for the red oaks in my area so I figured this year would be heavier. Three falls ago the nuts literally rained down on my house and the hickory nuts almost made it dangerous to take a walk. I know that white oaks produce acorns every year and red oaks every two and that some years are mast years. I am wondering if there is a connection between the galls and the light acorn harvest even though both reds and whites would be due this year? I am also wondering if these phenomena are being noticed else where in New England.

Habitat: suburban/yard

State: Massachusetts

Habitat: suburban/yard

A: Sounds like the reddish or greenish oak apple galls are those that haven't yet completely matured. I too have noticed these from time to time and always figured that the tree had "aborted" this gall before it matured - not sure if correct but this is my explanation. I'm most familiar with the brownish galls that fall from the tree when the leaves drop and have a small hole where the wasp emerged.

You're right that the red oak group of oaks requires 2 years for acorns to be mature but do produce seeds EACH year. Therefore, there is a mature crop and an immature crop on the red oaks each and every year. Hope that's clear?

Keep in mind that with all/most plants (to the best of my knowledge) there are "good years" and "bad years" of growth and seed production. You may have noticed that many of the flowering plants in your area vary from year to year. One year you may see lots and lots of a particular wildflower only to see few in the next few years. Plants do indeed cycle based on a variety of environmental factors. So, it's not surprising that your oak trees are not producing many acorns this season in your area. I don't believe that the gall infestation is causing the reduced acorn production - I'm guessing it's just a coincidence. You've asked some really good questions - scientists ask these kind of questions all the time - and although we're not always able to answer them completely, these questions help us focus more clearly and learn more about the natural world and certainly make it more interesing. Thanks for asking and I hope I've helped out a wee bit.

John Wiessinger ( September 5, 2006)