Surveys are intended to cover the entire population of mills. The mill surveys every five years are used to validate the annual estimates for years when the two series coincide. Data are updated every one to two years. Construction of processing capacity takes time, and changes in forest growth occur slowly. Thus, the relative proportions among sources of wood will not generally change rapidly.
Comprehensive data are available only for the years indicated.
This indicator conveys no information about the quality or species of wood being harvested, the amount of remaining inventory, or other qualitative aspects of timber harvest. Data for imports of forest products, published annually by the U.S. Department of Commerce, are widely available and generally accepted. Data are updated every five years. An updated analysis using data for 1996 will be available in early 2000. Data from these questionnaires are the only consistent direct estimates of timber harvest in the United States.