Kevin Allen, the state Department of Conservation and Recreation’s historic preservation planner, will open a door to the past Tuesday at a special presentation from 3 to 4 p.m. at the Upton State Forest. Allen plans to share recent discoveries about the property’s crumbling 80-year-old Civilian Conservation Corps administration building and dormitory cottage, show some newly discovered photographs, and outline this summer’s plans for the structure. According to Allen, the state forest’s CCC buildings are among the few remaining structures left in the country at the camps set up for Depression-era unemployed, who were put to work on forest conservation under the New Deal. Starting late this month, the state will begin stabilizing the building, Allen said. The first part of the project will be replacing the cinder-block piers that serve as its foundation, and repairing the roof. The preservation and design phase of the project will cost $30,000, while the foundation work will be about $40,000. Allen said the efforts to save the building may make the property more attractive for leasing by a private company or foundation. To save a space at the presentation, to be held rain or shine, call Allen at 617-626-1361or e-mail him at firstname.lastname@example.org. To attend, use the Westboro Road entrance and meet at the CCC parade grounds just off the parking lot.