The Capsula Mundi project by designers Anna Citelli and Raoul Bretzel has developed an organic, biodegradable burial capsule turns a human corpse into a nutrient rich source from which a new tree will grow.
Once enclosed in the capsule, the deceased are buried, then a seed is planted above the capsule. The seed takes root, draws nutrients from the body, and blah blah, so on and so forth.
More importantly, it reinforces the idea of the circle of life and could give the feel that your loved one remains with you.
It’s currently just a concept and outlawed by the Italian government, however, don’t be surprised if this is soon offered as standard burial practice.