What is considered "green" burial today was just considered burial a century ago. It's nothing really new, perhaps a new way of looking at the centuries old practice of family caring for a loved one after they have passed. Specifically, stewardship of resources and more intimate involvement of family members in most if not all steps of caring for a loved one until final disposition.
This quote from the linked article below sums it up neatly:
"What constitutes a green burial is not that complicated, at least from a consumer perspective, said Joshua Schlocum, director of the Funeral Consumers Alliance, a watchdog group for consumers. A "green burial," he said, is not about what you buy, it's about what you don't buy."
It boils down to three things, Schlocum said: No embalming, no metal or non-biodegradable casket and no concrete vault."
Read the full article here.