Question
We have multiple white oak trees planted in medians and in the landscape... in the past 3 yrs we have noticed that many of them have begun to display "clumping" of suckers/small internal twigs..
many for them by the time the they reach 8-10" die off.. and more suckering occurs.  mostly it seems to effect the lower 2/3rds of the tree.  Most of the trees effected have been planted in the last 7 yr.. all under 6" DBH... Any suggestions?  

We also have had a "gall" problem from attacks from wasps.. we are soil drenching with Imidicloprid twice a year.. which has helped.. but NOT solved the problem.. they only attack certain trees and not all.. Any suggestions

Answer
Hardwood trees  especially oaks have a tendency to sprout water shoots when planted as single open grown trees. This sprouting is the result of the sunlight hitting the trunk and the buds on the trunk will sprout. As the tree grows and the crown expands the lower limbs especially the sprout will die form the shading effect of the upper branches. This is normal self pruning. Not anything to worry about.

Twig and stem galls, such as the gouty oak gall and horned oak gall, are solid, woody masses that can girdle branches or make them droop from the sheer weight of the heavy growths. The galls can grow to more than 2 inches in diameter. Horned oak galls can be found on pin, scrub, black, blackjack, and water oaks while gouty oak galls occur on scarlet, red, pin or black oak.

These galls have a long and complex development that takes two or more years to develop. The first stage is a blister-like leaf gall that occurs along larger leaf veins. The second stage is a knotty twig gall that is started in mid-summer and becomes fully mature in 1 to 2 years. Adults emerge in the spring. Gouty oak twig galls are smooth; horned oak galls have horn-like projections. One female wasp can emerge from each horn.

Generally, insecticidal control is not satisfactory because the wasps are physically protected within the galls. Correctly timing applications to provide effective preventive control is difficult. Where practical, pruning of infested twigs may help to reduce the problem on lightly-infested trees. However, pruning is impractical if large trees are heavily infested.
I would not be too concerned with the galls they really do little to harm the tree. Here is web site that gives more information on oak galls. http://www.ento.psu.edu/extension/factsheets/gallsOnOak.htm

The Imidicloprid does little to prevent the galls since the insects are not really feeding on the plant and as a result do not intake the insecticide. The  Imidicloprid works well for aphids, scales and caterpillar type insects that feed on the plant tissue that has the insecticide in them and this kills the insect.