Where in the world are you?

The native habitat for these trees is generally north of a line from about Minneapolis to Boston and south of that they have many problems.

http://na.fs.fed.us/pubs/silvics_manual/volume_2/betula/papyrifera.htm

The Bronze Birch Borer is one of the many problems for birches, especially those planted in soils that are too dry. Most of the stands of the paper birch I see that are self planted are where the soils are wetter than normal.

kimmq is kimmsr

looks telephone poled ... can you pull back the soil and find out where the root flare is?

any significant grade change since planting?

ken

https://www.google.com/search?q=root+flare&source=lnms&tbm=isch&sa=X&ved=0ahUKEwislcnZpcjNAhXHFx4KHTcPC1gQ_AUICSgC&biw=938&bih=745&dpr=0.9

You are where the Paper Birch is native but is the area this tree is growing what that tree needs?

http://www.na.fs.fed.us/spfo/pubs/howtos/ht_birch/ht_birch.htm

The Bronze Birch Bore may also be part of the problem.

http://ento.psu.edu/extension/factsheets/bronze-birch-borer

You may also want to talk with the people at your local office of your
University of Minnesota Cooperative Extension Service.

kimmq is kimmsr