The theoretical basis for studying Jewish ethics:
The concept of Jewish Ethics as opposed to the concept of Halacha can be explained as an attempt to imagine what does the Jewish tradition have to say about ethics independantly of any limited halachic considerations. Otherwise there is no concept of Jewish ethics independant of or that is different from Halacha. There is only what the Halacha allows and what it forbids. For example Judaism may allow the taking of interest on a loan to a Gentile, but we can also say that Judaism is distasteful of the practice of taking interest. To discuss Jewish ethics we must imagine a world where everyone is an orthodox Jew and then ask what would Judaism say to do. That is what it is to extract the ethical teachings from the halachic context. The same exercise should be made when considering what Judaism has to say about protecting the environment. We must image all the land owned and populated by Jews and then consider what is right to do is such a case. Then we can apply Talmud concepts without making exceptions because the particular people involved may be Gentile.
Levital Cities of Refuge have a required 2000 cubit perimeter of natural forest. This can be understood as a requirement for greenery, a basic enviromental concern: plant and animal life, fresh air, beauty. And in fact that has been cited as an example of the Talmud's concern for the environment. But why do not other cities have a similar requirement? Perhaps these cities were especially important or regal. But a practical explanation may be that since the accidental murderer was supposed to flee here, were the city walls to be bare of forests the Goel Hadam could simply wait at the city gate and kill the murderer as he is about to enter the sactuary of the city. So, by placing a forest around the city, it becomes possible for the accidental murderer to sneak into the city unnoticed, under cover of the foliage, and escape the Goel Hadam. We are giving him a fighting chance.
The man - tree comparison in Deuteronomy is often understood to show man's similarity to a tree in that both are dependant on the soil and both produce valueable creations; fruit or other material things. While this comparison has validity in Drash, in Pshat it is the reverse. The Torah is teaching that one must not destroy a tree in battle because a tree is not a man that he is battling. It is an innocent part of creation and so should be protected. After the battle, whoever survives will want to use the trees for sustanance. The Torah is being rhetorical and saying, Is a tree a man that you would kill it!? But even if the comparison between a man and a tree is not really being made, the Torah is still teaching a valueable environmental lesson. Even on the soil of one's enemies, one needs to protect the natural environment, so much more so in ones own city. There is a respect here for leaving the world a clean a natural place for all to enjoy, even if it may seem advantageous at the time to destroy nature. Preserving the environment is more significant than transient needs.
In genesis Man is told to conquer and control the land. This presents man and earth as adversaries. The earth produces thorns and weeds but man must tame the earth like he would a wild animal. This makes sense especially when you consider the context of this command. There is but one couple of people and the whole world is empty. In such a case, there is a lot of hard work to be done just to survive. But when civilization has taken firm hold, and especially in our time where virgin land is hard to find and asphalt is everywhere, it becomes man's role to guard and protect nature. This state is ironically first mentioned in the Torah when man is created. He is created, we are told, to guard and tend G-d's garden. He is told to guard and protect nature, not to conquer it. Perhaps after man's sin he must rebuild some order into nature and then he is meant once again to guard nature as a treasure. The command to conquer nature is a command that becomes obsolete once it has been fulfilled.
The idea of man protecting nature appears in rabbinic literature which is written much later than the Torah. The Talmud was written at a time of a highly sophisticated civilization, and so it encourages a realtionship to nature where man must gurad and protect the natural world. Bal Tashchit is a rabbinic creation which best expresses the concept of man working in harmony with nature, not against nature. This development represents man's return to Eden.
Issues of environmental protection can be understood as a subset of property rights. A fruitful way of thinking about the environment in Jewish terms is to consider the environment as property of you and me and then asking what can I do with a shared commodity. When thinking about strip mining the hills of Virginia, we should ask first, who owns that hill? If the government owns it, then it is the property of the tsibur and their rights and needs must be protected. We must think in terms of best serving the all of the tsibur's needs without stealing from any one of them. Or is it ownerless, can I take it and ruin it? And if it is owned, the question becomes, What can I do in my land? Can I do what ever I want in my land? The Talmud in Baba Batra says, no. You can't dig a ditch in a way that will detrimentally affect your neighbor (i.e. too close to the edge of his land). So, even if you own something 100% you cannot do everything you want with it. You must consider your neighbor and are not allowed to damage him. Strip mining my land may affect my neighbor.
More interesting are the questions, Who owns the air and who owns the oceans? Can I polute my air even if it affects your air? This is a question of property rights. The air and the oceans are logically the property of the tsibur, so again, their best interests must be kept in mind when deciding anything.
Other examples of the Talmud's concern for seemingly benign things that I may do in my land that are forbidden because of their affects on others is in found in Baba Batra again. I can't hang laundry in certain areas. This is a concern for the public's need for beauty. I can't set up a bursky (tanning shop) in certain areas. This is a concern for the effect of my actions on other people's environment, smelling up the air.
Sadly, modern society is far too permissive in what it allows people to do and fails to fully consider all the ramifications of these actions on the lives and health others.