ukkot, which begins tonight, reminds us that long before we were the People of the Book we were the people of the land. We lived in harmony with nature — because our lives depended on it.

In our urban environment, we’ve lost touch with our roots. No longer involved in physical work, we work out in an indoor gym, which we drive to, sweating to electronic music on electronic machines.

We stuff our clean clothing into automatic dryers — because we don’t have time to hang the wash — and we spend our free time rushing around while yakking on our cell phones, chatting online or watching the latest episode of “Friends.”

If machines were supposed to liberate us, where has our time gone? And what about our land? Not only have we failed to care for ourselves, we have neglected our environment big time.

It’s not just esoteric stuff about global warming and the ozone layer. It’s clear-cut logging in Northern California’s forests. It’s radioactive waste off the Farallon Islands. It’s contamination in San Francisco’s Hunter’s Point and pollution from refineries in Richmond and Martinez.

And it’s not just marbled murrelets and spotted owls. By failing to care for our land, we are sabotaging bodies that are already overstressed by too many machines and too little leisure. We are becoming an endangered species in an endangered land. Our fish and our foods have already become afflicted, and so have many of our residents.

It’s life-threatening illnesses, it’s allergies and it’s stress.

Sukkot — like the Shabbat on which it begins this year — commands us to stop and to create an island of time in our busy lives. We are reminded that all of our dwellings on this planet, like our bodies, are temporary. We are all renters, whether we live in $4 million mansions or shanties.

Spending a week in a sukkah, like tent camping or backpacking, gets us in touch with our pre-urban roots, and with our fragility. A forerunner to Thanksgiving, Sukkot is also a harvest celebration, a time to relish the fresh fruits, grains and vegetables of the land — rather than wolf down the manufactured foods that so many Americans exist on.

If you’re an urban dweller without the ability to dine in a sukkah, pack a picnic and take it to a park. Even if you don’t cook, buy organic produce and fill your sack.

And while you’re at it, take a look around you. The unstable sukkah dwelling is now our planet. What can you do to renew its foundations? Our lives depend on it.