Well-meant efforts to build roads into Brazil's Amazon rain forest may end up destroying it and costing the country far more ecologically than it will gain economically, experts said on Thursday. But the country may end up losing its most valuable resource-its rain forest-in the process, William Laurance of the Smithsonian Tropical Research Institute, Michigan State University researcher Mark Cochrane and teams at Oregon State University and the Biological Dynamics of Forest Fragments Project in Brazil said.