The situation is complicated by an existing infestation of pine beetles throughout the Black Hills. The Mountain Pine Beetle (Dendroctonus ponderosae) and Pine Engraver Beetle (Ips pini) are the two species primarily responsible for the damage. A 2003 Forest Health Highlight-South Dakota, produced jointly by the U.S. Forest Service and South Dakota Division of Resource Conservation and Forestry, listed 270,200 trees damaged by the Mountain Pine Beetle covering 189,700 acres as well as 120,700 trees damaged by Pine Engraver Beetles involving 45,200 acres. The bulk of this damage occurred within the Black Hills. Add to this the intermittent drought conditions throughout the Black Hills over the past several years and the likelihood of tree mortality becomes even greater due to combined stress.
Research is needed to clearly delineate the effects of deicing in the Black Hills on pine trees adjacent to the roadside as well as the extent of any damages with respect to the surrounding forest. This project would provide the information necessary to modify current procedures to minimize impact, if necessary.