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Paired Watershed Timber Harvesting Research Study

Who Helped and Who Funded This Research?

The North Carolina Forest Service (NCFS) partnered with US Forest Service’s Eastern Forest Environmental Threat Assessment Center (EFETAC) to conduct this research study. Additional project or financial assistance came from NC State University, NC Department of Agriculture and Consumer Services, Watershed Science LLC, and Weyerhaeuser.

Funding was acquired from the US EPA 319 grant program to examine the effectiveness of forestry Best Management Practices (BMPs) for protecting water quality in the Piedmont region.

Where Did This Research Take Place?

Map Image of neuse river basin and study sites at far northwest end

Researchers evaluated three “pairs” of similar forested watersheds located in the NCSU Hill Demonstration Forest and the NC Department of Agriculture and Consumer Services Umstead Research Farm. These sites were located in the Neuse River Basin.

What Did Researchers Do?

Timber within one watershed of each pair was harvested using a clearcut logging method. The other watershed in each pair served as a non-harvested reference. Within each harvested watershed, loggers complied with the Forest Practice Guidelines Related to Water Quality (FPG’s) and followed appropriate voluntary BMPs. Streams were monitored for approximately 3 years before and after the timber harvest. The researchers recorded weather data, streamflow, soil characteristics, vegetation characteristics, and water quality factors.

What Did Researchers Find? (Some Quick Highlights)

  1. Stream discharge increased following the timber harvests. This illustrates the need for installing and maintaining BMPs!
  2. Small increases in nutrients and sediment were observed following harvest. However, these levels never exceeded N.C. water quality standards and returned to preharvest levels in less than 3 years!
  3. Partial harvesting within the buffer zone overstory provided more sunlight to the ground alongside the stream, which fostered the growth of more diverse ground cover and shrub vegetation. For the duration of the study, the stream water temperature never exceeded N.C.’s maximum allowable limit. Researchers recommended that the intent of leaving trees within the buffer should be to provide long-term vegetative structure, soil stability, and stream shade.

Where Can I Read More Details About the Findings?

This page updated: Tuesday, August 29, 2023 10:37

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