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Goal: Sustain Our Nation’s Forests and Grasslands Managing coastal forests for timber, water, and carbon storage

Loblolly pine forests in the southern U.S. produce wood for the world, benefiting local and national economies. Long-term monitoring of the full rotation of pine stands reveals that forest carbon and water cycles are tightly coupled. In the coastal plain region, growing multi-age stands optimizes water supply, carbon sequestration, and other ecosystem services at the landscape level.

An eddy flux tower containing meteorology instruments.
Meteorology instruments on an eddy flux tower measure carbon and water cycles in a pine plantation forest on the coastal plain in North Carolina. USDA Forest Service photo.

Loblolly pine provides major economic benefit in the southern U.S. along with clean water, carbon sequestration, wildlife habitat, and other ecological services. Since 2005, USDA Forest Service scientists and partners have been conducting long-term studies to understand ecosystem responses to forest change on North Carolina's lower coastal plain. Using advanced hydrometric methods, the scientists have measured water and carbon budgets at managed loblolly pine stands in various stages of growth for 14 years.

The researchers found that carbon and water are tightly coupled in these stands. Trees used more water as they matured, increasing from planting until stabilizing at 10-15 years. This means more runoff from an area when stands are harvested, replanted, and for at least a decade afterward. Young managed pine forests release more carbon than they store. Around year ten, the trees became net carbon sinks, storing more carbon than they lose.

This research provides new insights on how forest management can mitigate greenhouse gas emissions and runoff in managed forest areas—and suggests that a mosaic of forest stands of different ages across the landscape can help managers sustain ecosystem services such as clean water and long-term carbon storage.