Pine barrens are found in coastal plain areas and are characterized by dry pitch pine and scrub oak forests upland interspersed with swamps and bogs in the lowlands. Pine barrens are home to a variety of plant and animal life, often including unique specimens not found elsewhere. Examples of pine barrens on the east coast include southern New Jersey, which has protected 1.1 million acres of pine barren land; Long Island; Cape Cod and New Hampshire.
The soil in pine barren country is layered, with a top layer that's very dry, sandy and acidic. When it rains, the water flows though the soil, leaving very little in the way of nutrients behind. In the upland areas of pine barrens, these conditions make it the perfect place to find pitch pine, which grows in well-drained soil. The dry soil composition hinders the breakdown of organic matter and, as a result, pine needles and bark cover the forest floor, acting as kindling for frequent forest fires, according to The Nature Conservancy. These fires act as maintenance device by eliminating non-native plants.
Pine barrens are also characterized by wetlands such as swamps, bogs and streams. Here, the sandy, acidic soil mixes with water to create muck that supports plants, ferns, grasses and sedges that tolerate these poorly drained conditions, according to the Pinelands Preservation Alliance. The water is dark due to the presence of high concentrations of iron and organic material.
A clay layer is present underneath the sandy soil. In some areas of the pine barrens, this layer is closer to the surface due to geologic upheaval. This clay holds water better than sand and prevents all of the nutrients from passing though. Many plants cannot access this water, however, due to the small size of the clay's pores, according to New Jersey Pines and Down Jersey. Clay is easily identified when wet because it is slippery due to its microscopic particles.