A group of highly respected American technical and medical experts, using conservative assumptions, have concluded that it could cost Chevron up to tens of billions of dollars to clean up oil waste discharged into Ecuador’s rainforest and compensate local communities for the damage it caused over the 26 years it operated a large oil concession, according to valuation assessments submitted Thursday to the Ecuador trial court…While the high end of the damages range of $113 billion is substantially greater than the $27.3 billion damages number set forth in a report in 2008 by court-appointed expert Richard Cabrera, some categories of damages were found to be lower than those estimated in that report…