What is the saying that there is an Ailanthus altissima bud tree growing on the grave?

Don't worry too much about this, because Toona sinensis has strong vitality, fibrous roots can sprout new buds and seeds can germinate. According to what you said, I estimate that there are seeds of Toona sinensis in bird droppings, so new buds have sprouted. I suggest you pull it out, because it is not a place, and then plant it next to the cemetery as a souvenir, because Ailanthus altissima is also one of the modern good landscaping trees.