Plant Diseases/Tree Disease
I have a pin oak tree covered with very hard balls growing around the branches which break off and fall to the ground. The balls look like the branch. The pin oak next to it has a few on it. Can you tell from this description what these may be and what can we do about them, if anything?
These swellings (galls) are probably insect in origin. There are some very tiny wasps that can cause these to occur. Using your computer, "Google" Horned Oak gall and compare the photos. There are some insecticides that can be used, but timing of application is important and I am not so sure how effective they are. There is quite a bit of useful information on treatments available on the web also.