In 1975-1976, pine trees killed by the southern pine beetle (Dendroctonus frontalis Zimm.) in a 2170-hectare (5362-acre) area at the William B. Umstead State Park in central North Carolina, were monitored by sequential color infrared aerial photography. From 1973 through summer 1975, beetles in 350 infestation spots killed more than 20,500 pines on 137 hectares (339 acres). From October 1975 to July 1976, an additional 301 dead pines were detected at 146 tree mortality centers. Southern pine beetles were associated with 98 percent of these dead trees. Pine mortality dropped rapidly from 248 trees killed in fall and winter at 120 spots to 9 trees killed in July at six spots. The volume of timber killed during the outbreak exceeded 16,000 m3 (7500 cords) of roundwood valued at more than $240,000. Strictly speaking, this is not an economic loss because the Park's management goal is to maintain a "natural forest."