Tree wound dating
The problem has more to do with people spraying Roundup to kill weeds around the trees (drift gets on the bark) or spraying Roundup to kill "suckers," those shoots you're seeing that emerge from around the base of the tree.If you're not doing either of those, I don't think that past spray is causing any harm. just cut off any branches that are so infected that the knots kill off the wood from the infected point outward.For example, a palm tree can be compared with another tree whose age is known in order to get an estimate of the palm’s age.Radiocarbon dating has also proven useful in dating these trees.The worst thing that can happen is if the wounds get infected with a fungus. That was the idea of paints and tars, but the drawback of those is that they can trap moisture and maybe small amounts of infection that then can spread when not exposed to air. I should mention that there's been research showing a correlation between Roundup and bark splitting.I doubt that would explain it since you waited a full year between applying Roundup on the maple stump and planting the cherry.This can be done by wrapping a tape measure around the tree to find it’s circumference and then dividing that number by 3.14.
This use of tree-ring dating to find the age of a tree is also known as dendrochronology.
Although cutting into and counting the rings of a tree is one of the best ways to determine its age, it is possible to get a good estimate of a tree’s age without cutting into it.
First, measure the diameter of the tree at a point 54 inches from the ground.
The knots you're seeing could be a wood disease called "black knot." Cherries are fairly susceptible to this. In minor outbreaks, your tree should growth through this, too.
As for the suckers, cherries have a tendency to keep sending those up.