Hi,
I was walking around checking on my trees when I saw these scars on the upper branches of my Santa Rosa plum. They seemed fine last year ( summer and fall). The tree has similar scars on the bark at the base of the tree above the grafting point. Is this a fungal disease or is some insect attacking my plum? Or is this wind/winter damage? Any recommendation on what to do. My other Alderman plum does have any of such scars. I bought this tree about 3 years ago from Lowe's. I'm in NJ Jersey.

Thanks,
Jerseymec.