Assessment of Loblolly Pine Decline in Central Alabama
Loblolly pine (Pinus taeda L.) decline has been prevalent on upland sites of central Alabama since the 1960's. The purpose of this study was to compare Forest Health Monitoring (FHM) standards and protocols with root health evaluations relative to crown, stem, and site measurements. Thirty-nine 1/6 acre plots were established on loblolly decline sites in nine central Alabama counties. Sites were selected on federal, state, and private industrial lands to measure variables of decline symptoms, age classes and management procedures. A two-root sampling procedure, selective media, and soil baiting assay methods were used to isolate pathogenic root infecting fungi. Pitfall traps collected root-feeding insects from which Leptographium species were recovered. FHM indicators of tree crown conditions were recorded on all pines in the plots. Preliminary results showed a significant correlation between live crown ratio and incidence of Leptographium spp. We recovered Leptographium from damaged roots in eighty-four percent of plots. The pine basal area was significantly reduced with increased incidence of Phytophthora cinnamomi Rands, with P. cinnamomi being recovered from the soil root zone in 50 percent of the plots. Histological examination of root damage indicated a significant correlation between reduced growth and root wounding.