Roughly 2,500 trees and shrubbery find sanctuary at Starhill Forest Arboretum near Petersburg, Illinois, where co-founders Guy and Edie Sternberg practice what they promote in tree conservation. Having founded the arboretum in 1976, the Sternbergs kept at least one existing tree near their residence on the 50-acre property. It’s an Osage Orange from about 1930,…