Which soils are included among Pennsylvania's natural barrens?

• A. Serpentine, shale, and sandstone
• B. Serpentine, limestone, and shale
• C. Limestone, granite, and serpentine
• D. Shale, sandstone, and limestone

Answer: (A)

Pennsylvania’s natural barrens are defined by very low-nutrient, well-drained soils that create harsh growing conditions, favoring specialized, hardy plant communities. Serpentine soils come from ultramafic rock and are especially infertile, with low calcium relative to magnesium and often high heavy metals, which limits many plants and allows unique species to thrive. Shale and sandstone soils, when shallow and acidic, also drain quickly and provide little fertility, producing the barren-like conditions typical of these habitats. In contrast, calcareous or nutrient-rich soils such as those derived from limestone or granite tend to be more fertile and support different vegetation, so they aren’t part of the barren habitats. Therefore, the soils included are serpentine, shale, and sandstone.