Sick Aspen Trees
It appears that you have either a Black Canker or Sooty-Bark Canker. There is no cure but you can avoid further damage by avoiding wounding of the trunk. The trees may live for many years with the cankers.
When I looked up sick Aspen trees I saw many pictures that looked like my tree and they were called some type of black fungus. Do you know of any treatment for that?
Other than pruning out the damage, I don't know of any other treatments - and your tree has the problem on the trunk so unless you cut down the trees and try and grow the suckers, there is no solution that I'm aware of.