Rj/
crawgarden has provided a couple of very good links. Read through them, and get a better understanding of what you are observing.
Also, take a few more pictures (at least one showing the WHOLE plant) of that handsome young
Quercus macrocarpa, and maybe some different angles of the insect galls where they are occurring.
In and of themselves, the galls are a general curiosity but mostly NOT a negative impact on most Oaks. These are easy to remove from young plants like yours, because you can reach every one of them. Be careful in initial removal, so that no excess bark damage is incurred. Removal may be useful in how many more times you observe these galls in quantity, but the insect that causes these galls is endemic - so you will always likely see some over the lifespan of your tree.
The most fun is observing these kinds of galls on different species of Oaks (
Quercus sp.). There are many different oaks, and it seems like there are a lot of different related species of insects which use oaks for laying their eggs and growing the next generation. I also suspect that each species of oak reacts differently to this intrusion, and forms a gall that is species-specific. I think it is White Oak (
Quercus alba) that forms a roundish spongey gall. I had collected a couple and kept them in a kitchen cupboard JUST FOR THIS KIND OF QUESTION. My ever-loving spouse just threw them out earlier this week in advance of cleaning said cupboards. So, I blame her for me not being able to provide a "show and tell" opportunity.
There is another species which creates a paper-thin spherical gall which would make you think your oak is growing ping pong balls. I'm not remembering which oak that is, but I think it is in the Red Oak group.
Last word: The Horny Gouty Galls which form on Pin Oak (
Quercus palustris) can be and are deleterious to long term health of that tree species. I live near and drive under an allée of Pin Oaks twice daily on my commute. In the 33 years that I've watched these trees grow toward maturity, I have also watched the density of galls increase annually. Some of these trees have succumbed, standing dead with bark shedding and branches dropping. While I do not believe that the galls alone were the primary cause of death, they certainly inhibited natural and healthy increase in twig and branch diameter. I believe that contributing factors include planting a
palustrine and
acidophile species on droughty calcareous soils; regular insults to the basal trunk bark by mowing implements; and regular application of glyphosate products onto the tree trunk while trying to control grass/weeds around the basal area of these trees.
So: tree health is key. All these native plants grew up around all kinds of things intent on eating them, stealing their resources, or crowding them out in favor of themselves. Life is competition. Human involvement should include knowledge of what should be; what has been created that isn't quite what it should be; and what can reasonably be done to insure success regardless.
The more you know...
https://www.davey.com/insect-d....
https://www.missouribotanicalg...
https://extension.psu.edu/gall...
https://hyg.ipm.illinois.edu/p...
