A wedding shoot in a graveyard!?
The idea strikes me as very oblique and incoherent in a way. Most people are dying to get in there, not sure about brides-to-be...
If the tree must be featured, the couple should be place behind the bench or the bride seated on it and the groom behind, with the entire arrangement tightly cropped to exclude the irrelevant background of gravestones. I see no aesthetic benefit including the stones. A moderate telephoto lens would assist in compressing the scene and framing.
Here in Australia, King Billy Pine (Athrotaxis selaginoides) frequently reach 1500+ years in age in remote alpine rainforest areas of Tasmania, and this is considered young. Not sure if they have certificates!