Gregory A. Reams

The Southern Annual Forest Inventory System

The Southern Annual Forest Inventory System (SAFIS) is in various stages of implementation in 7 of the 13 southern states serviced by the Southern Research Station. The SAFIS design is an interpenetrating design where the n units (1/6 acre plots) are divided into k = 5 panels, each panel containing m = n/k units. Panel 1 plots are measured in year 1, panel 2 in year 2, etc., such that all plots have been visited by the end of year 5. The panel cycle is repeated into perpetuity. Each panel, in effect, is a 5-year periodic survey with complete overlap of sample units. Numerous estimation schemes are possible, and we explore five possible options. The five options are (1) use existing periodic inventory programs to produce 5-year survey estimates by adjusting all five panels to a common year, (2) analyze each annual panel independently, (3) produce 5-year estimates by combining the five panel estimates by varying the weight given to each panel, (4) base inventory estimates on mixed estimation where actual and predicted values are combined, and (5) use imputation techniques such that unmeasured plots are filled in with imputed plots. A two-phase method for forest area estimation that uses the known map marginals from a thematic map is presented as an alternative to photo interpretation-based estimates.

Synchronic large-scale disturbances and red spruce growth decline

Tree-ring data from the USDA Forest Service Forest Inventory & Analysis and other independent sources were used to study coincidence of changes in growth and large-scale disturbances. Numerous studies report that mean radial growth of red spruce (Picearubens Sarg.) declined synchronously throughout its range in the early 1960s. We use red spruce tree-ring data from most of the major studies to show that the synchronicity of red spruce growth decline is likely the outcome of the large-scale disturbances that occurred throughout the northeastern red spruce ecosystem in the late 1930s to early 1950s. Large-scale disturbances are either not detectable or not present in the same time interval in the southern Appalachians. This appears to correspond to an absence of a 1960s radial growth reduction in this region.

Detecting and Predicting Climatic Variation from Old-Growth Baldcypress

Tree-ring data can extend back in time for thousands of years allowing researchers to reconstruct certain environmental factors that have left an imprint or signal in the tree-ring record. Typically, these factors include reconstructions of annual precipitation or temperature for months or seasons to which a particular tree species is sensitive. Over the last several decades, scientists have used tree-ring records in novel ways to investigate the timing and extent of such natural phenomena as volcanoes (Baillie and Munro, 1988), earthquakes (Sheppard and Jacoby, 1987), El Nino/southern oscillation (Stahle and Cleaveland, 1993), fire (Swetnam 1993), carbon dioxide (CO2) (Graybill and Idso, 1993), and synchronous landscape-level disturbances (Reams and Van Deusen, 1993) by recognizing the possibility that various signals may be recorded in the growth record of trees, depending on microsite characteristics, geographic location, and disturbance history (Fritts 1976).