TSCA and The Southern Pine Beetle

July 1997

It has been alleged that the TSCA emissions starting in about 1991 have played a significant role in the pine beetle infestations in nearby stands of pine trees. The following is a brief outline and chronology of the pine beetle in Oak Ridge and the effect of radiation on pine trees

The Southern Pine beetle has been indigenous to the Southeastern United States for many decades. It, as well as other plant infestations, thrives especially well in the monoculture plantings used in tree farms. In the early 1950's the Atomic Energy Commission, now the Department of Energy (DOE), planted dense stands of pines with the intent to reap some profit from the vacant land on the Oak Ridge Reservation (ORR). Similar steps were taken at the Savannah River site. In the late 1950's, the Oak Ridge National Laboratory (ORNL) undertook the forestry management efforts required by the project.

In the early 1960's, the first infestations of the Southern Pine beetle were found and in spite of treatment as advised by the Forest Service, the infestation spread rapidly in the dense mono-culture plantings. This infestation was brought under control by a mixture of cutting, burning and pesticides. The infestations are now widespread on the ORR and follow the pattern typical of such infestations, waxing and waning with weather and other natural cycles. The most recent serious infestation probably resulted from the cessation of the ORNL forestry management program causing the stand to become more vulnerable.

It is well known that trees do suffer stress from industrial emissions, e.g., acid rain, SO2, NOx and particulates. Thus, while there is little doubt that the pine trees may have suffered some prior man-made stress, the known resistance of trees to radiation does not suggest that the small elevations on the ORR can be responsible.

Trees and Radiation

The lethal radiation dose for pine trees is around 10,000 rads with some dependence on the type of radiation. Deciduous trees common to this region fall in the range from 20,000 to 30,000 rads. These numbers must be compared to the local background radiation level of 0.3 rem per year and the ORR elevation attributable to the site operations of about 0.003 rem per year. It is difficult to see how ORR radiation levels as low as 1,000,000 times smaller than the lethal dose for pine trees can be responsible for wide spread beetle infestations that are little different in nature from infestations outside of the ORR.

Since the human lethal dose is in the range of 250 rads (LD50), if the radiation level has ever been high enough to affect pine trees then the effects on humans and other mammals should have been drastic and easily observed.

Likely Causes