Assessment of Regional Productivity in North Carolina

Abstract

One goal of productivity research is to present and analyze patterns of actual and potential primary productivity of landscapes. The data available for such determinations have greatly increased since initiation of the International Biological Program (IBP); and models developed from these studies will be used eventually to predict production for almost any ecosystem. At present, however, productivity data from intensive site studies are of limited value for estimating landscape productivity patterns. No matter how careful the production measurements, the values obtained are in the strict sense valid only for the particular sites and time periods of investigation. For a proper assessment of landscape production patterns we need numerous measurements that can be related to the pattern of the landscape itself. Various agricultural and forestry statistics are readily available and can be used to demonstrate landscape production patterns. Most of these data express primary production for the commercially usable portion of each land-use category (e.g., seed production for crops and mercantile lumber for forests). The data can be converted, however, to estimates of total primary production through the use of appropriate conversion factors—the ratios of total primary production to the commercial yield. Similar analyses can be performed on any land-use category if the production-yield ratios are known. This chapter summarizes 2 years of research in North Carolina, which included the utilization of U. S. Forest Service and state agricultural and land-use data for estimating rates of net primary productivity for all land-use categories in the state’s 100 counties. Additional estimates were made of total net primary production for each county, an estimated net primary production rate for the entire state, and an estimate of the state’s total net primary production. More complete documentation is available in Whigham et al. (1971) and Sharp (1973).