Bronze Leaf Disease on swedish columnar aspen

[Doug in Calgary]

I've sequentially lost three swedish columnar aspens to what I now think is bronze leaf disease. I replanted with a new tree in the same location after the previous one died. The recommendation is to carefully dispose of all leaf and branch material. What else can I do, if anything, to prevent BLD recurrence if I replant again? I checked the other swedish columnar aspens in my yard and in those of neighbors and don't see any BLD. The location is tight so other species would be crowded.

I'm in the tree hostile climate of Calgary, Alberta. Swedish Columnar Aspens generally do well here.