The source for Tu B'Shvat is the opening Mishnah of the Talmudic Tractate Rosh Hashana: "The Academy of Hillel taught that the 15th of Shvat is the New Year for the Trees."

 What does that mean, "New Year for the Trees?"

 Tu B'Shvat is technically the day when trees stop absorbing water from the ground and instead draw nourishment from their sap. In Halacha, this means that fruit which has blossomed prior to the 15th of Shvat could not be used as tithe for fruit which blossomed after that date.

 So what relevance does this have for us in the 21st century, when most of us are not farmers? In various places, the Bible compares a person to a tree:

• A person is like the tree of a field…" (Dvorim 20:19)
• For as the days of a tree shall be the days of my people." (Isaiah 65:22)
• He will be like a tree planted near water…" (Jeremiah 17:8)

Why the comparison? A tree needs the four basic elements in order to survive – earth, water, air and fire (sunshine). Human beings also require the same basic elements. Let us see how by analyzing these four essential elements individually.

Earth: A tree needs to be planted firmly in the earth. The soil is not only the source through which nourishment is absorbed, but also provides room for the roots to grow.

This is true of a person as well. The Talmud explains; "A person whose wisdom exceeds his good deeds is likened to a tree whose branches are numerous, but whose roots are few. The wind comes and uproots it and turns it upside down. But a person whose good deeds exceed his wisdom is likened to a tree whose branches are few but whose roots are numerous. Even if all the winds of the world were to come and blow against it, they could not budge it from its place." (Avot 3:22)

A person can appear successful on the outside. "But if the roots are few" – if there is little connection to one's community and Torah heritage – then life can send challenges that are impossible to withstand. "A strong wind can turn the tree upside down." A person alone is vulnerable to trends and fads that may lead to despair and destruction. But, if a person – irrespective of wealth and status – is connected to his community and Torah heritage, then "even if all the winds of the world were to come and blow against it, they could not budge it from its place."

People require a strong home base, where Judaism's values and morals are absorbed, and which provide a supportive spiritual growth environment.

Water: Rain-water is absorbed into the ground and – through an elaborate system of roots – is carried throughout the trunk, branches and leaves of the tree. Without water, the tree will wither and die. The Torah is compared to water, as Moses proclaims: "May my teaching drop like the rain" (Dvorim 32:2). Both rain and Torah descend from the heavens and provide relief to the thirsty and parched. The Torah flows down from G-d and has been absorbed by Jews in every generation. Torah gives zest and vitality to the human spirit. A life based on Torah will blossom with wisdom and good deeds.

Deprived of water, a person will become dehydrated and ultimately disoriented, even to the point where they may not be able to recognize their own father. So too, without Torah, a person becomes disoriented – to the extent that they may not even recognize their Father in Heaven.

Air: A tree needs air to survive. The air contains oxygen that a tree needs for respiration, and carbon dioxide for photosynthesis. In an imbalanced atmosphere, the tree would suffocate and die.

The Torah (Bereishit 2:7) states that "G-d breathed life into the form of Man." The Hebrew word for "breath" – nesheema – is the same as the word for "soul" – neshama. Our spiritual life force comes, metaphorically, by way of air and respiration.

We use our senses of taste, touch and sight to perceive physical matter. (Even "hearing" involved the perception of sound waves). But "smelling" is the most spiritual of senses, since the least "physical matter" is involved. As the Talmud says (Brachot 43b); "Smell is that which the soul benefits from and the body does not."

In the Holy Temple, the daily incense offering (sense of smell) was elevated to the once-a-year Yom Kippur offering in the Holy of Holies. The Talmud (Sanhedrin 93a) also says that when the Messiah comes, he will "smell and judge" – that is, he will use his spiritual sensitivity to determine the truth about complex matters.

Fire: A tree also needs fire – sunshine – to survive. The absorption of energy from the sunlight activates the process of photosynthesis, a chemical reaction that is essential for the growth and health of the tree.

People too need the physical warmth of fire and sunshine to survive. But we also need to absorb and reflect the spiritual warmth and sunshine of friendship, which is the essence of Judaism. As the Torah states in Vayikra 19:18, "Love your friend as yourself." And Rabbi Akiva states that this verse is the greatest principle of the Torah (Talmud Yerushalmi, Nedarim, Chapter 9.)