I thought of this yesterday.
When a couple gets married, they plant a sapling together. They tie a white ribbon to the topmost branch of the sapling, as their tree (and family?) grow, they add different colored ribbons to the tree, each branch representing a person and each color represents something different. These family trees could keep a visual record of their family's history.
White could represent marriage, green for a birth, black for death… Feel free to expand upon this however you like. When family members die, the mourning of the ones left behind is not considered complete until the deceased's black ribbon has been added to their branch.
I dunno! Just a couple ideas. Feel free to expand however you deem fit.