About this time every year, the age-old rabbinic story of Honi, The Circle Maker makes its rounds.

It goes like this: Honi was a minor miracle worker in first century Palestine. Once, in his youth, he happened upon an old man planting a carob tree. Now the carob tree was legendary for taking 70 years to mature, and Honi found it odd that someone so advanced in years would bother planting one.

“Old man,” Honi called out. “What are you doing?”

“I am planting a carob tree,” the old man replied.

“And do you believe that you will live to eat of its fruits?” asked Honi.

“No,” said the old man. “But I ate carobs when I was young. So just as my ancestors planted for me, I am planting for my children.”

This story was part of my childhood. I learned it in the context of Tu B’shvat, the midwinter Jewish holiday of the trees. The point was for us children to learn: (1) that trees are an essential part of life and land, and that humans have an obligation to plant and care for them; and (2) that bonds of love and responsibility must guide the generations — else the world dies.

This time-tumbling bond of intergenerational concern and activism is called m’dor l’dor in Judaism: from generation to generation. Each generation acknowledges the gifts and blessings bequeathed to it from those who came before. And each generation is mindful of its obligations to the ones yet to come.

My friends and I heard this story every year, so often that we took it for granted. The message for me became trite; the tree just metaphor.

Until recently, when I turned 60 and started to plant fruit trees myself. I wanted to celebrate the birth of my grandchildren and leave something that would provide for them over the years. But that seemingly simple desire toted with it a lot of assumptions, and it was through them that I began to see the pathos, wisdom and generosity of the old man in a new light.

To plant a fruit tree is a leap of faith. Unlike a vegetable garden that will ripen, and die, in a matter of months, a fruit tree needs years to mature. It assumes and demands patience, steadfastness, tending to without reward, stability and health of place for a long while. In Ohio in the late 1700s, for example, homesteaders proved their commitment to place, and thus their right to claim100 acres, by planting 50 apple trees and 20 peach trees.

Fruit trees demand constancy of care and knowledge. One generation must not only tend to them, but must transmit its skills to the next generation: how to prune and mulch; what companion plants attract the good bugs and which repel the bad; how best to propagate the best-tasting fruit; how to withstand the cycles of drought and frost.

Today, even more than in the past, planting fruit trees has become an act of faith, for the trees will require a stable climate. They will need the same growing conditions in 80 years in this location that they need now. So planting a fruit tree transforms the orchardist into an investor, and an advocate for climate, land and a livable future.

Even more, planting fruit trees is a spiritual endeavor. It forces us to peer into the future and releases us from the tyranny of self-absorption and the sometimes blinding and constraining focus of “now” that tends to guide modern culture and economics. Instead, it pulls our gaze — and our hearts — beyond the bounds of our lifetimes.

Planting trees, therefore, when much of one’s life has been spent, is the ultimate act of unconditional giving. Those who eat of its fruit years from now can never repay us. Indeed they are not even likely to bother thinking much about us, much like Honi never thought about the planters of the fruit that he enjoyed in his younger years.

Perhaps that is the prerogative of youth and innocence: to accept the gifts of the world as a given. But we, as a species, are no longer young or innocent. We live now in an era when all of Earth is touched and molded by the acts of Man. We now realize that the Earth’s future, its gifts and its systems, are in our hands. We affect them, force them, disturb them, alter them. And not just for a little while, but for possibly forever.

So we, too, must be like the old man. We must invest in planting trees, building new systems, and discovering new sources of energy that will yield fruit perhaps only after many of us are gone. But that is the promise we owe the generations.