I am not sure what this is but when my river birch tree get new leaves they...
What immediately comes to mind are spiny witch hazel galls. https://extension.umd.edu/learn/ipm-series-birch-trees-hg58
http://pender.ces.ncsu.edu/2013/05/what-is-wrong-with-my-river-birch/ This does not require treatment. If this does not match up with your symptoms, send photos. vw
The expert may be right about the gall but we looked it up but will the kill the leaves? We have attached pictures. It seems like the leaves sprout get the red bumps and then shrivel up and turn brown.
From your photos it looks like the tree may be a type of Prunus, not a birch. The photos are out of focus and we cannot make an accurate diagnosis. For more information contact your extension http://www.cceontario.org/temp2.asp?id=contact-cce