SOUTHERN PINE BEETLE-INDUCED MORTALITY OF PINES WITH NATURAL AND ARTIFICIAL RED-COCKADED WOODPECKER CAVITIES IN TEXAS

Southern pine beetle (Dendroctonus frontalis) infestation is the major cause of mortality for Red-cockaded Woodpecker (Picoides borealis) ca vity trees in loblolly (Pinus taeda) and shortleaf (P. echinata) pines . Recent intensive management for Red-cockaded Woodpeckers includes th e use of artificial cavity inserts. Between 1991 and 1996 we examined southern pine beetle infestation rates of pines with natural vs artifi cial cavities in loblolly and shortleaf pine habitat on the northern p ortion of the Angelina National Forest. No significant difference exis ted in the rate at which southern pine beetles infested and killed pin es with natural cavities vs those with artificial cavity inserts (chi( 2) = 0.84, P > 0.05). Southern pine beetles infested and killed 20 nat ural cavity trees (25.6%) during the 5-year study (78 cavity-tree year s) and 19 artificial cavity trees (18.8%; 101 cavity-tree years). Data for the entire Angelina National Forest indicate that 40% (25 of 62) of the cavity trees killed by southern pine beetles between 1984 and 1 996 had been the nest tree during the preceding breeding season. The a nnual infestation rate of cavity trees appears to be related to southe rn pine beetle population levels of the surrounding forest. Use of art ificial cavities is essential to maintain sufficient numbers of usable cavities for Red-cockaded Woodpeckers in-Texas. Why southern pine bee tles appear to preferentially infest active Red-cockaded Woodpecker ca vity trees is still unknown, but may be related to southern pine beetl e attraction to resin volatiles produced when woodpeckers excavate res in wells and/or changes in the levels of infestation-inhibiting tree v olatiles as a result of cavity and resin well excavation.