Tuesday, Feb. 14, is Valentine’s Day — formerly known as St. Valentine’s Day. Monday, on the other hand, is Tu B’Shevat, a/k/a the New Year for Trees, Judaism’s millennia-old "Earth Day."

It is a safe — and sad — bet that more Jews will celebrate the former than the latter. As one person pointedly explained to me, Valentine’s Day "is an American holiday that celebrates love." The inference, of course, is that Judaism has no such glorious day on its calendar.

Well, it does have Tu B’Shevat, which celebrates our love for the world around us (a love we observe in the breach — including the one in the ozone layer). It does have Tu B’Av, which is still marked at least liturgically; once upon a time, it was akin to Sadie Hawkins Day. And it does have Shabbat, which comes once a week, not once a year, and which very much is about celebrating love — of our spouses and our children specifically and all of creation generally. These, alas, are "Jewish" observances, with "Jewish" too often interpreted as ancient, arcane, and irrelevant to modernity.

Please.

Let us first address the "American" holiday that falls every Feb. 14. It was established by Pope Gelasius back in 496 CE to celebrate the martyrdom of a priest named Valentine, although there is confusion as to when he lived, and how, when, and where he died.

For equally unclear reasons, he was designated the patron saint of engaged couples, happy marriages, love, and lovers, as well as for plague, epilepsy, fainting, bee keepers, travelers, and young people, although these seem quite unrelated to love. He also was designated as the patron saint of greetings, something the greeting card industry should gratefully acknowledge each year all the way to the bank.

How he became the patron saint of love and marriage is sort of clear.

One of the "Valentine" candidates supposedly was killed because he defied an order to stop marrying young couples, said order having been issued by the Roman emperor Claudius II Gothicus.

As for the saint’s day becoming Lover’s Day, that dates back to the Middle Ages, and a belief then prevalent in England and France that the birds begin to mate on Feb. 14. For this we have the testimony of one Geoffrey Chaucer, a poor speller, who notes that "on Seynt Valentyne’s day … every foul cometh … to choose his mate."

Clearly, Valentine’s Day is as American as steak-and-kidney pie.

Tu B’Shevat, on the other hand, is clearly un-American, at least as long as this country continues to ignore our ailing environment while it wreaks havoc with our natural resources.

That is because the 15th day of Shevat (15 is what the "Tu" stands for) epitomizes how ancient, arcane, and irrelevant to modernity Judaism is not, and specifically in this case in environmental and ecological areas.

For the record, anyone who takes time to study the Torah, both the written and oral versions, will discover that Jewish law is not outdated; it has enduring relevance to our lives today in virtually every area of our lives.

What could be more ecologically sound, for example, than letting the land lie fallow one year out of every seven? More humane than giving beasts of burden one day off each week?

More personally consequent than spending one-seventh of our lives taking a rest from the mundane?

Shabbat does not belong to another era, when life was far simpler. It belongs to a time when life is complex and demanding. It forces us to slow down and get back in touch with what is really important.

If more relevance is needed, then consider this: By forcing us to conserve ourselves and all we control, Shabbat makes conservation a part of our lives in ways most profound.

Based on a verse in Deuteronomy prohibiting the destruction of the fruit-bearing trees of an enemy in wartime, a principle of law was established, "bal tashchit," which literally means, "You may not destroy."

In the Babylonian Talmud tractate Shabbat 67b, a Babylonian sage named Rav Zutra uses this verse to prohibit the wasteful use of fossil fuels or their derivatives. "He who covers an oil lamp or uncovers a naphtha [lamp] infringes the prohibition of wanton destruction," because these are techniques used to speed up the burning of those fuels.

There are laws that protect air quality and water quality. Thus, for example, in BT Bava Batra 18a, we are told: "A man may not open a bakery or a dyer’s workshop under another person’s storehouse [because of the smoke], nor make a cowshed there [because of the smell]…."

Further on (‘4b), it states: "A fixed threshing-floor must be kept 50 cubits from a town [because of the harm from airborne pollutants, in this case the flying chaff]. A man should not fix a threshing-floor on his own estate unless there is a clear space all round of 50 cubits. He must keep it away from the plantation of his neighbor and his ploughed fallow [field] a sufficient distance to prevent damage being caused."

And on the very next page (‘5a), it adds: "Carrion, graves, and tanyards must be kept 50 cubits from a town [because of the bad smell]…."

One provision allows a person to sue for damages if someone does something to lessen the quality of his or her water supply.

There are laws that protect against noise pollution. Residents even can obtain an injunction against a business opening up near them if they can show that the business will create undue noise. (See BT Bava Batra ‘1a.)

These aren’t laws created today. They are laws created ‘,000 and 3,000 years ago.

So seriously does Judaism take its environmental concerns that there is even a blessing to be recited when one sees the first trees bud and the first flowers blossom in the spring: "Blessed are You, O Lord our God, who omitted nothing from His world, but Who created within it good creatures and beautiful trees for people to enjoy."

It is something for some Jews to consider this Monday, Tu B’Shevat, as they last-minute shop for their Valentine’s Day gifts.