Here's a few from Leopold. He's hard to beat when it comes to conservation.
"Acts of creation are ordinarily reserved for gods and poets, but humbler folk may circumvent this restriction if they know how. To plant a pine, for example, one need be neither god nor poet; one need only own a good shovel. By virtue of this curious loophole in the rules, any clodhopper may say: Let there be a tree—and there will be one."
"The outstanding scientific discovery of the twentieth century is not television, or radio, but rather the complexity of the land organism. Only those who know the most about it can appreciate how little we know about it. The last word in ignorance is the man who says of an animal or plant: "What good is it?" If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering."
"Do we realize that industry, which has been our good servant, might make a poor master?"
"[W]e seem ultimately always thrown back on individual ethics as the basis of conservation policy. It is hard to make a man, by pressure of law or money, do a thing which does not spring naturally from his own personal sense of right and wrong."
“A man may not care for golf and still be human, but the man who does not like to see, hunt, photograph or otherwise outwit birds or animals is hardly normal. He is supercivilized, and I for one do not know how to deal with him.”
And my personal favorite:
"WHEN THE DEER HUNTER SITS DOWN HE SITS WHERE HE CAN SEE AHEAD... THE DUCK HUNTER SITS WHERE HE CAN SEE OVERHEAD.. THE NON-HUNTER SITS WHERE HE IS COMFORTABLE."
"Yes like I said it all boils down to morals. What you think is right doesn't make a person wrong because they think different