Factors Affecting The Ability Of Rosa Multiflora To Invade And Persist In The Understory Of Southern Appalachian Forests

Rosa multiflora (MR) is an invasive shrub brought to the United States from east Asia in the 1800s. MR is shade intolerant, but recently, has invaded the forest understory in the southern Appalachians, raising the question of how it persists under shady conditions. MR may succeed in the understory by growing in canopy gaps and may tolerate varying light conditions. Also, MR has evergreen stems, which may augment CO2 assimilation by leaves. Weekly phenological measurements on MR shrubs showed that MR leafed out before native vegetation and kept some leaves longer than native species. Thus, MR gains a competitive advantage by using high light prior to canopy leaf out and after canopy senescence to gain carbon. Gas exchange measurements showed higher total daily carbon gain in the spring before canopy leaf out and lower amounts when the canopy was full out and even after senescence. The photosynthesis of MR leaves and stems differed significantly. MR appears to be successful in the forest understory because of its early spring carbon gain before canopy leaf out, due to its early leaf out. The influence of stem photosynthesis may contribute to carbon gain in the winter when the canopy is leafless.