The cosmopolitan common reed (Phragmites australis) has been expanding into previously unoccupied wetland habitats throughout North America. This invasion by a non-native haplotype of Phragmites has become a major concern due to a reduction in plant diversity, reduction of faunal biodiversity, and changes in ecosystem structure. A randomized complete block design was used to compare the efficacy of two herbicides, glyphosate (Rodeo, Dow AgroSciences, IN, U.S.A.) and imazapyr (Habitat, BASF Corporation, NC, U.S.A.), on 1-ha Phragmites monoculture in a shallow borrow pit. Six foliar experimental treatments were applied consisting of (1) 2% glyphosate formulation, June application; (2) 2% glyphosate formulation, September application; (3) 2% imazapyr formulation, June application; (4) 2% imazapyr formulation, September application; (5) 5% imazapyr formulation, June application; and (6) 5% imazapyr, September application. Experimental plots were monitored yearly for two years after treatment. Relative importance values (RIV) were determined to assess the efficacy of herbicide treatments. We report that imazapyr foliar application is statistically superior to glyphosate in reducing Phragmites RIV, with no significant differences between the 2 and 5% formulations. Both herbicides are more effective in reducing Phragmites RIV if applied early in the growing season (June). No significant differences in non-Phragmites plant recolonization were observed between herbicide treatments over the two-year time course. These results suggest that imazapyr is superior in reducing Phragmites RIV, and that earlier applications of herbicides may be more effective on Phragmites. However, managers must note that adjacent nontarget plant species may be negatively affected by earlier treatments.
Oak crop trees were evaluated for their biological potential in 18 even-aged upland hardwood stands of sprout origin on good sites (oak S.I. 75 or better) in the upper Piedmont of South Carolina. These were unthinned stands, aged 20 to 40 years since clearcutting. Scarlet oak (Quercus coccinea Meunchh.) was the largest and most common acceptable crop tree, with straight boles generally free of epicormic branches, but was infrequently classed as desirable due to the poor natural pruning of its sizable and persistant dead branches. Southern red oak (Q. falcata Michx.), although smallest in diameter, was the most desirable crop tree of the oak species, due to its small branches that prune cleanly in these well-stocked stands. White oak (Q. alba L.) generally rated desirable except for many trees with epicormic branches, a well-known trait of this species. Black oak (Q. velutina Lam.) crop trees, although fewer in number, had good bole form with good pruning and few epicormic branches. Most crop trees were free of swollen butts and any sign of butt rot, and many were free of multiple dead or suppressed ancillary sterns. Overall, 56% of all oak crop trees were classified as desirable or better with excellent potential to develop into mature sawtimber.
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