Warren has been a forestry consultant since 1981 and during his career, he has been responsible for a variety of forestry related duties, including timber inventories, timber and timberland appraisals, forest management, timber sale administration, and a variety of consulting projects that involve such issues as forest management investigations, forest product pricing and timber or resource availability. Warren has prepared appraisals for acquisitions, dispositions, estate and gift tax matters other purposes on timberland properties located across the southeastern United States ranging is size from a few acres to over 500,000 acres. He has also been qualified as an expert witness in the fields of appraisal, forestry and forest management in numerous District Courts as well as U.S. District Courts.