For nearly a century, two towering ash trees have shaded our house and stood like sentinels watching over it. Within the last decade, however, one of the ashes suffered a mortal wound, and in the intervening years the rot and carpenter ants did their business. The arborist told us there was no saving the tree and we took it down. Since we wanted to plant another seedling (a weeping willow) in its place, we had to grind the stump completely out of the ground. “You’ll have to get rid of that stump,” the arborist said, “or nothing else will grow…