Abstract High population densities of red oak borer, Enaphalodes rufulus (Haldeman), are believed to be a major contributor to recent widespread oak mortality in the Ozark Mountains of Arkansas. The intent of this research was to expand our knowledge on specific aspects of this insect's biology, life history, and distribution by trapping flying adults in the Ozark National Forest during emergence of 2001, 2003, and 2005 cohorts. Passive flight intercept trap catches revealed that preferred flight height and thus optimal trap placement for monitoring populations was close to the base of the dominant/co-dominant northern red oak, Quercus rubra L., canopy. Flight periods and peak flight were different in 2001 and 2003. Emergence occurred a week earlier in 2001 vs. 2003. Peak flight occurred over a 3-week period from mid Jun to early Jul in 2001 in contrast to 2003 peak flight, which occurred the first week of Jul. Male to female ratios were 1.9:1 and 1.4:1 for 2001 and 2003, respectively. In 2003, sex ratios...