This fall, the University released the results of its first comprehensive tree inventory. Conducted by two grad students, it found that the more than 7,000 trees on central campus store millions of pounds of carbon. The biggest specimen is a pignut hickory on Libe Slope whose trunk is 79 inches in diameter; the oldest is this 350-year-old white oak, located below Gannett Health Services. The survey, done as part of Cornell’s sustainability efforts, identified nearly 300 species; the most common is the northern red oak, comprising more than 10 percent of trees on the Hill.