Forest Productivity & Technology

Background 

Long-term site productivity is intrinsic to the concept of sustainable forestry. Not only is sustained site productivity directly linked to future timber production, but also to the many environmental values provided by healthy, productive forests. Research conducted over the last decade has demonstrated that generalizations of tree growth responses to management practices are often inaccurate because process controls vary from site to site. It is therefore important that site productivity research go beyond growth responses to the site processes controlling those responses so that site-specific controls can be understood and applied beyond bounds of individual studies.

It is important that NCASI continue investigating interactions of site productivity factors and intensive management regimes that may include shorter rotations, greater and more frequent site removals of biomass and nutrients, more extensive use of forest chemicals, and use of genetically improved seedlings. Results from these investigations should be valuable for determining how any negative consequences can be prevented or ameliorated, and what tradeoffs may be involved.

Goal 

Develop an understanding of relationships between intensive forest management, soil processes, and long-term site productivity as a basis for developing management and mitigation strategies across different site types.

Examples of Recent or Ongoing Tasks 

• Effects of Thinning, Vegetation Control and Fertilization on Nitrogen Cycling in Southern Pine Plantations – This project is studying effects of thinning, understory vegetation removal, and harvesting on the fate of fertilizer N across a loblolly pine site gradient in Louisiana.
• Regional Study of Fate of Fertilizer Nitrogen Applied to Forests – This study is integrating data from existing fertilizer-water quality studies to develop and validate an N cycling-water quality model to assess the fate of fertilizer N for different site-management combinations and to identify important N loss and retention mechanisms.
• Long-term Productivity of Pacific Northwest Coastal Douglas-Fir Plantations – This study is examining the effects of varying harvest intensities with and without vegetation control, soil compaction, tillage, and fertilization on tree growth and underlying site processes such as soil nutrient availability, soil physical properties, and biophysical site characteristics.
• Long-Term Site Productivity of Upland Southern Pine Plantations – NCASI staff recently organized a symposium on this subject that included top scientists from academic, agency, and industry research programs across the South. Staff also served as guest editor for a special issue in the journal Forest Ecology and Management containing the articles resulting from the symposium.
• Implications of Harvest Residue Removal for Sustainable Site Productivity – This task is synthesizing literature related to the effects of harvest residue removal on site productivity, with a particular focus on intensive management systems in North America, Scandinavia, and Australia/New Zealand.