PRESSURE TREATMENT OF SOUTHERN PINE POLES WITH CHLOROTHALONIL IN HYDROCARBON SOLVENT

A series of end-sealed southern pine pole stubs was treated with chlor othalonil in hydrocarbon solvent. Over sixty sections were treated usi ng various combinations of initial seasoning (kiln-drying, steam-condi tioning), treating temperature (ambient, heated), initial air pressure , and final conditioning (steam flash + vacuum, expansion bath + vacuu m, steam distillation + vacuum). Disks removed from the treated sectio ns were analyzed for preservative gradient. Results are discussed in t erms of treatability and the impact of treating variables on preservat ive retention, penetration, and gradient shape. These data indicate th at acceptable treatment of southern pine pole stock can be obtained wi th either steam-conditioned or kiln-dried pole stock. The use of heate d solution appears to be preferred over ambient solution, although acc eptable treatment can be achieved at ambient conditions.