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📘 Read the full study in Silva Fennica (2026): https://doi.org/10.14214/sf.26004 or contact Dr. Chad Bolding for more information.

Many forested wet flats across the U.S. South face a management challenge: these stands are too wet for conventional full-tree harvesting equipment and too small to justify the higher costs associated with specialized shovel logging systems. As a result, timber is often left unmanaged and unrecovered from wet sites. New research from Drs. Chad Bolding, Joe Conrad, and Mr. Tim Miller with the Langdale Center for Forest Business at the University of Georgia and their Italian research partners Raffaele Spinelli and Natascia Magagnotti evaluated whether cut-to-length (CTL) harvesting systems, which have low ground pressure and good trafficability in wet conditions, offered a cost-competitive solution.

Wet Site Challenges

Wet mineral flats and forested wetlands are common throughout the southern Coastal Plain, but harvesting these areas can be difficult and expensive. Traditional harvesting systems often struggle with soil conditions and trafficability, while specialized wet-site systems can require larger tracts and higher timber volumes to be economically feasible. This creates a management gap where many smaller wet sites remain underutilized.

Testing Cut-to-Length Harvesting in Georgia

Researchers evaluated a CTL harvesting operation on two small wet sites in Georgia using a Ponsse Ergo harvester and Elephant forwarder equipped with flotation tracks designed to reduce ground pressure and improve mobility. CTL systems perform in-woods tree processing which leaves limbs, tops, and offcuts in the forest, providing additional ground cover and leaving organic material that can be used for future tree growth. The study measured machine productivity, harvesting costs, and operational challenges under real-world conditions.

Key Study Findings

The CTL system successfully harvested timber on sites that would be difficult to access with conventional full-tree harvesting systems. Tree size was the most important factor influencing harvester productivity, with larger pine trees producing the highest output. The study also found that computerized bucking – which determined how the trees were delimbed and cut into smaller sections – helped maximize value recovery from harvested stems, an important advantage when harvesting high-value timber.

While the CTL harvester performed well, the forwarder became the primary bottleneck. Wet terrain, scattered log piles, and the requirement to load trucks reduced overall system efficiency. Forwarder productivity was affected more by operational and site conditions than by timber characteristics.

Another challenge related to integrating the CTL “cold logging” system into a predominantly “hot logging” supply chain. In conventional full-tree harvesting systems in the U.S. South, log trucks are loaded upon arrival at a site (hot logging). CTL systems work best when the harvester and forwarder work separately to maximize utilization and minimize delays, often resulting in log trucks being loaded at a separate time convenient to operations (cold logging).

Improving Productivity and Lowering Costs

The UGA and Italian researchers identified several practical changes that could significantly improve CTL performance in the U.S. South. Machine tracking software or more careful operation planning could help forwarder navigation in the wet sites and thereby increase productivity. If a dedicated tracked loader were added to hot load trucks, estimated system productivity could increase by 53% while also reducing harvesting costs. Alternatively, using setout trailers to load logs would increase productivity by 32% and result in the greatest reduction in harvesting costs. Both approaches allow the forwarder to focus on moving wood instead of spending valuable time loading trucks.

Key Information for Forestry Professionals and Stakeholders

For forest managers, landowners, and logging contractors, findings indicate that CTL harvesting can provide a viable option for recovering timber from small wet tracts that might otherwise remain unmanaged. With better harvest planning and improved loading logistics, CTL systems could help expand management opportunities across challenging wet-site environments.

The broader public benefits when forestland remains actively managed and productive. Sustainable harvesting supports rural economies, generates income for landowners, and encourages long-term forest stewardship. By creating new opportunities to manage difficult-to-access sites, CTL harvesting can help ensure that more forest resources contribute to economic and environmental sustainability.

Acknowledgements: The authors acknowledge Miller Timber Services, Inc. and Rayonier, Inc. for providing field sites, coordinating harvesting activities, and collaborating with the research team.