Is Biodiesel good or bad for the environment?

We know that emissions from vehicles running on biodiesel are good, but what about the consequence of cutting down long established forests around the world in order to plant biodiesel crops?

This is a major concern. It appears to me that humankind will never cease to rape the earth and will continue to disregard the long term consequences of such actions.

Now that businesses believe that being "green" will earn more green in their bank accounts, there are plenty of speculators investing in the effort but they aren't really being ecologically minded in their approach.

Is this just normal human madness or will people ever change their ways.

http://www.squidoo.com/biodieselcontroversy

hmmm I was thinking about this the other day.
I agree that people have to take into consideration the environmental costs of planting so much of a few fuel crops where there had been forests, ecosystems, or food crops.
As well as the environmental impact there is also the social one. Using food crops and land which could raise food for fuel could put a strain on the global food supply, pushing prices up and increasing hunger. It could become a social justice issue if wealthier people can afford to pay higher prices to fuel their cars while other people throughout the world cannot afford to put food on the table. Of course the same thing happens when good farm land is turned into condos, so I don't think that issue is unique to biofuel.
Then there's also the question of who owns the refineries. I've read a few articles explaining that in order for the increase in demand for corn and soybeans to really benefit farmers they have to own the refineries (or at least the refineries should be locally owned), otherwise the price the farmer receives will again be pushed down, and the profits from the corn will be extracted from the community.

On another note, David Pimentel, a Cornell scientist and noted opponent of biofuel claims that biofuel requires more energy to produce than it creates, although I think his analysis is not generally accepted- at least not by proponents of biofuel.
It's a complicated issue, but for sure biodiesel isn't a free source of energy that can be used in abundance without conservation. Sometimes I feel that there is so much emphasize on finding the perfect fuel that will never run out and had no environmental consequences, that people forget to figure out ways to conserve.

Using corn for ethanol production has little net energy output, therefore it does not help anyone to use as much energy to produce a fuel as the fuel contains in itself. If sugar cane is used to produce ethanol then it is "good". Other fuels such as switchgrass and wood byproducts are a more complicated issue.