Hmm that one gives me an idea immediately. I am thinking: groom standing behind the bench; bride seated. Fairly wide lens, lowish perspective (eye level to the bride). Narrow depth of field.
If there are other people in there, then a choice relative of the bride beside her on the bench, and everyone else arranged as you please. You can permute youngest and oldest relatives etc. and knock the whole thing out methodically.
Generally I think a standing posture for the groom will help reconcile the scale of the tree with whomever is on the bench. If you do have b&g seated then I think you will need to take a lowish perspective to frame them better aainst the tree (assuming the bench isn't movable).