Long-term effects of forest herbicides on plant diversity in pine plantations in the southeast
Conservation of biological diversity is an important issue on public and private forests worldwide. As concern for diversity maintenance escalates, more pressure will be placed on the forestry community to understand the efjfects of silvicultural treatments on biodiversity and its sustainable management Biodiversity conservation in intensively managed forested regions will depend (at least partially) on species growing in tree plantations, their margins, SMZs, and rights-of-way. Within the-Southeast, pine plantation acreage is projected to double by 2040, mainly replacing natural pine forests. Replacemeut and establishment occur through intensive harvesting, using herbicides and mechanical treatments, burning, planting closely-spaced genetically-improved seedlings, and often fertilizing. The singular or additive effects of all these treatments lire often assumed to limit plant species richness and diversity, yet little had been documented to support or refute that assumption. To learn more ahout diversity changes following herbicide treatments for site prepamtion and release, I have led two teams in conducting both a region-wide research project at 13 locations in. 7 states, and a study series in Central Georgia on 7 locations in 3 provinces. The following generalizations come from the tidings of these studies as well as from others' related research.