(א) ארבעה ראשי שנים הם. באחד בניסן ראש השנה למלכים. ולרגלים. באחד באלול. ראש השנה למעשר בהמה. רבי אלעזר ורבי שמעון אומרים באחד בתשרי. באחד בתשרי ראש השנה לשנים. ולשמיטין. וליובלות. לנטיעה. ולירקות. באחד בשבט ראש השנה לאילן. כדברי בית שמאי. בית הלל אומרים בחמשה עשר בו:
(1) The four new years are: On the first of Nisan, the new year for the kings and for the festivals; On the first of Elul, the new year for the tithing of animals; Rabbi Eliezer and Rabbi Shimon say, on the first of Tishrei. On the first of Tishrei, the new year for years, for the Sabbatical years and for the Jubilee years and for the planting and for the vegetables. On the first of Shevat, the new year for the trees according to the words of the House of Shammai; The House of Hillel says, on the fifteenth thereof.
The 15th of Shevat on the Jewish calendar—celebrated this year on Saturday, February 11, 2017—is the day that marks the beginning of a “new year” for trees. This is the season in which the earliest-blooming trees in the Land of Israel emerge from their winter sleep and begin a new fruit-bearing cycle.
We mark the 15th of Shevat by eating fruit, particularly from the kinds that are singled out by the Torah in its praise of the bounty of the Holy Land: grapes, figs, pomegranates, olives and dates. On this day we remember that “man is a tree of the field” (Deuteronomy 20:19), and reflect on the lessons we can derive from our botanical analogue.
(Chabad.org - http://www.chabad.org/library/article_cdo/aid/468738/jewish/Tu-BShevat-What-and-How.htm)
(19) When in your war against a city you have to besiege it a long time in order to capture it, you must not destroy its trees, wielding the ax against them. You may eat of them, but you must not cut them down. Are trees of the field human to withdraw before you into the besieged city?
(יט) כי האדם עץ השדה. הרי כי משמש בלשון דלמא שמא האדם עץ השדה להכנס בתוך המצור מפניך להתיסר ביסורי רעב וצמא כאנשי העיר, למה תשחיתנו:
(19) "Is a man a tree of the field?" Here, the word "ki" functions in the sense of "perhaps": "Perhaps a tree of the field is human, and should be included in the proscription [of the town] before you, and should suffer with hunger and thirst just like the human inhabitants of the city?" Why would you destroy it!?
(יג) ראה את מעשה האלהים כי מי יוכל לתקן את אשר עותו - בשעה שברא הקדוש ברוך הוא את אדם הראשון, נטלו והחזירו על כל אילני גן עדן, ואמר לו: ראה מעשי כמה נאים ומשובחין הן, וכל מה שבראתי, בשבילך בראתי, תן דעתך שלא תקלקל ותחריב את עולמי, שאם קלקלת אין מי שיתקן אחריך. ולא עוד שאת גורם מיתה לאותו צדיק.
(13) Look at God's work - for who can straighten what He has twisted? (Ecclesiastes 7:13). When the Blessed Holy One created the first human, He took him and led him round all the trees of the Garden of Eden and said to him: “Look at My works, how beautiful and praiseworthy they are! And all that I have created, it was for you that I created it. Pay attention that you do not corrupt and destroy My world: if you corrupt it, there is no one to repair it after you.
How might the above text connect to Tragedy of the Commons, a concept at the heart of modern environmentalism:
The thesis of the tragedy of the commons is that individuals are inherently selfish and usually place their own interests first in using commonly owned resources, thereby resulting in their depletion.
https://conservationbytes.com/2011/02/28/classics-tragedy-of-the-commons/
Or this definition from the EPA:
Environmental stewardship is the responsibility for environmental quality shared by all those whose actions affect the environment.
https://archive.epa.gov/stewardship/web/html/
Environmentalists often use the language of "protecting the earth for future generations." Is this language effective? What might be gained or lost by talking less about the future and more about the present?
(23) When you enter the land and plant any tree for food, you shall regard its fruit as forbidden. Three years it shall be forbidden for you, not to be eaten. (24) In the fourth year all its fruit shall be set aside for jubilation before the LORD; (25) and only in the fifth year may you use its fruit—that its yield to you may be increased: I the LORD am your God.
Huffington Post 2/25/2016 Reforestation: The Attainable Sustainable
The reasons for this transformation were not workshops about reforestation, nor farmer manuals, nor “experts” from other countries paying farmers to plant trees. Rather, the change to a tree-planting culture occurred over a five-year relationship between Don Sebastian’s family and the Guatemalan technicians from the Alliance for International Reforestation, Inc. (AIR) or as it is known in Guatemala, “AIRES”.
AIRES uses a five-year model, recognizing that it takes time to see the benefits of specific trees. The microbusinesses then succeed because neighbors have had time to observe the positive impact of growing trees that prevent mudslides and replenish soil.
How might it help that we're eating "local food" as opposed to traditional Tu B'Shevat foods grown in Israel?
While there is no official definition of local food, the 2008 Farm Act defined a “locally or regionally produced agricultural food product” as one that travels less than 400 miles from its origin, or within the state in which it is produced. Many people consider food produced within a 100-mile radius as local. Local food is sold at farmers markets, roadside stands, U-pick operations, through community supported agriculture, Farm to School programs, and food hubs that distribute food to restaurants, hotels, etc.
In the United States, conventionally produced foods are often said to travel 1,500 miles from farm to plate. Rich Pirog, senior associate director of the C.S. Mott Group for Sustainable Food Systems, found that conventional food distribution was responsible for 5 to 17 times more CO2 than local and regionally produced food.
Small farms also more readily adopt environmentally friendly practices. They often rebuild crop and insect diversity, use less pesticides, enrich the soil with cover crops, create border areas for wildlife, and produce tastier food (since industrial food is bred to withstand long-distance shipping and mechanical harvesting).
http://blogs.ei.columbia.edu/2012/09/04/how-green-is-local-food/
What are some other Jewish texts about appreciating nature?
Ellen Bernstein, Ecology and the Jewish Spirit: Where Nature and the Sacred Meet, 13
Moderns too often pose the wrong questions to religion. They ask what Judaism says about the “environmental crisis” and “nature”...Rather, Judaism’s ecological message emerges when we observe what is sacred in Judaism. How are we to treat what is holy? And what is humanity’s place amid the holiness? The Jewish understanding that the earth belongs to God attests to the fact that the earth and everything in it is holy, and this concept of holiness, kedushah, is the beginning of a unique Jewish environmental ethic.
ולא יאבדו אפילו גרגיר של חרדל בעולם, ויצר עליהם בכל אבדון והשחתה שיראו, ואם יוכלו להציל יצילו כל דבר מהשחית בכל כחם מדיני המצוה.
[Righteous people] will not destroy even a mustard seed in the world and they are distressed at every ruination and spoilage they see; and if they are able to do any rescuing, they will save anything from destruction, with all their power.
אילן אילן במה אברכך
אם אומר לך שיהו פירותיך מתוקין הרי פירותיך מתוקין שיהא צילך נאה הרי צילך נאה שתהא אמת המים עוברת תחתיך הרי אמת המים עוברת תחתיך אלא יהי רצון שכל נטיעות שנוטעין ממך
Tree, tree, with what shall I bless you?
If I say to you that your fruits should be sweet, your fruits are already sweet;
if I say that your shade should be pleasant, your shade is already pleasant;
if I say that a stream of water should flow beneath you, a stream of water already flows beneath you.
Rather, I will bless you as follows: May it be God’s will that all saplings planted from your seed may be as fruitful as you are.
(1) Happy is the man who has not followed the counsel of the wicked, or taken the path of sinners, or joined the company of the insolent; (2) rather, the teaching of the LORD is his delight, and he studies that teaching day and night. (3) He is like a tree planted beside streams of water, which yields its fruit in season, whose foliage never fades, and whatever it produces thrives.