Hello, I've just bought a new home in Prince Edward Island which is zone 5b. We have an abandoned hedgerow behind our house and there are numerous small trees there which are struggling for survival. It appears they are infected with black knot. This disease seems to be prevalent in plums and I'm wondering if anyone is able to tell from these photos whether these are plum trees. They are approximately 6 feet high and the parts that aren't dead are flowering right now. I understand that all of these trees will need to be removed and burned but I'm wondering about what I can plant in their place. I don't think any fruit trees would be a wise choice but what about other trees such as birch, spruce or butternut? Or should this area be cleared and left to sit empty for a period of time? Does anyone have any suggestions or have you dealt with this fungus before? Thanks very much.