Armed groups in Colombia are driving peasants off their land to make way for plantations of palm oil, a biofuel that is being promoted as an environmentally friendly source of energy...Thousands of families are believed to have fled a campaign of killing and intimidation, swelling Colombia's population of 3 million displaced people...Several companies were collaborating by falsifying deeds to claim ownership of the land, said Andres Castro, the general secretary of Fedepalma, the national federation of palm oil producers...Unlike coca, the armed groups' main income source, palm oil is a legal crop and therefore safe from state-backed eradication efforts...