Question
We have lived on our property for forty years. We have many red oak trees that drop their acorns in late September and early October. I am seeing something this year that I have never seen before. there are fewer acorns dropping but many small ( the size of a pea), fuzzy, white sead looking things that are coming down from the oaks. I have tried to find an answer for why this is happening or what I am seeing and whether I should be concerned about my oak trees. Thank you for taking the time to consider my question.

Answer
I think it is aphids. These insects have sucking mouth parts and can secrete a waxy material that is white. One of these is the Wooly oak aphid. You should be able to feel the sticky honeydew on the foliage. And it maybe raining down under the tree.
The fluff is waste materila from the aphids.
 Since it sounds like this are large trees, I would use a product called Bayer Advanced Tree and Shrub Insect Control. It is applied to the soil around the tree and the roots will carry it to the foliage and when the aphids suck the plant juices they are killed. BUT It is too late in the year to treat now. The trees are beginning to shut down for the winter and they will not move the material from the roots to the foliage. I would apply next Spring.
These aphids will not kill the tree but may cause the tree to drop leaves.  This treatment  should stop the population.  

Here is a web link to this product check with your local nursery store. http://www.bayeradvanced.com/tree-shrub-care/products/12-month-tree-shrub-insect