I want to know the answer to the following question:
What are there 8,100 acres of in Raleigh?
All the background I'm provided with is that "The J. C. Raulston Arboretum, an 8-acre (32,000 m²) arboretum and botanical garden in west Raleigh administered by North Carolina State University, maintains a year-round collection that is open daily to the public without charge.". Is that enough to answer the question?