These are rust galls, which are caused by a fungus. It is a very common condition of serviceberry (Amelanchier sp.), which is the type of tree you have. The fungus passes between two different host plants at different times of the year (Juniper and rose family plants like serviceberry, crabapple, and hawthorn). The severity of rust infections can vary from year to year, depending on weather conditions.

At this point, no fungicides will treat or cure this infection. Since this disease is more of a cosmetic issue rather than something that would harm the overall health of your tree, we discourage the use of fungicides to suppress the rust. 

For a young tree like this, be sure to keep up with watering when we get into very dry periods (less than an inch of rainfall per week). Also, ensure your mulch is not too deep (no more than 3" deep), and keep the mulch pulled a few inches away from the trunk. Steady moisture is important for the establishment of new trees and helps to minimize stress on them.

Here's a video that explains more about rust on serviceberries.

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Christa