M. Boyd Edwards

Forest herbicide influences on floristic diversity seven years after broadcast pine release treatments in central Georgia, USA

Maintenance of biodiversity is becoming a goal of forest management. This study determined effects of broadcast pine release herbicide treatments on plant species richness, diversity, and structural proportions seven years after treatment. Three study blocks were established in central Georgia. Plots 0.6–0.8 ha in size were planted to loblolly pine (Pinus taeda L.) in the Winter of 1982–83 and then treated with imazapyr (Arsenal), glyphosate (Roundup), and hexazinone (Velpar L. and Pronone 10G) in 1985. In 1992, overstory and understory (<1.5 m height) layers were examined utilizing stem and rootstock counts and basal area of overstory species and cover of understory species. ANOVAs were used to test for significance using a randomized complete block model. We found no effect of treatments on species richness. Diversity, measured separately for overstory and understory layers by Shannon-Wiener and Simpson indices, also was not influenced significantly by treatments. Arsenal significantly decreased Diospyros virginiana L. and increased Rubus argutus Link and legumes. Hexazinone treatments generally decreased Quercus nigra L., and Roundup significantly reduced Vaccinium spp. compared to the Check. We concluded that herbicide release treatments did not decrease overstory or understory plant species richness and diversity seven years post-treatment.

Relationship of macrofungal population to silvicultural treatments in a recently harvested pine forest

Abstract Both mechanical and chemical treatments of clear-cut pine forests have been shown to promote both growth and vigor in forest regeneration. Although the relationship between certain macrofungi and the forest ecosystem is well established, there is little information regarding the effects of silvicultural site-preparation treatments on the occurrence of these fungi. Randomly selected plots that received no (additional) treatment after clear-cutting [control (C)] and plots that were sheared roller-chopped (SC), and chopped and herbicide-treated (CH) following clear-cutting were sampled for visible macrofungal fruiting bodies. Fifty-five fungal genera were collected from the entire study areas. There were 29, 41 and 32 species collected in C, SC and CH plots, respectively. Fifty percent of the fruiting-body biomass occurred within CH plots, while 30% and 17% occurred within SC and C plots, respectively. The degree of correlation between both site-preparation and fungal biomass varied according to species.