Q.Silver Birch trees
What does cankers on silver Birch trees look like and can spores affect Rose bushes nearby?
Downtoearthdigs
Answered on October 8, 2017
http://extension.colostate.edu/topic-areas/yard-garden/cytospora-canker-2-937/
http://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-diseases/canker-diseases
https://extension.psu.edu/pests/plant-diseases/all-fact-sheets/cankers
I am not sure what is happening to the birch trunks in the pictures, but here is some information on canker diseases in birch and other trees. A university extension agent or arborist may also be able to help you diagnose your tree's problem.
Was this answer useful?
00