Bur oak, Quercus macrocarpa (Michx.), in Riding Mountain National Park
Little in known about the extensive 'Quercus macrocarpa ' stands occurring in Riding Mountain Na ional Park (RMNP). The main topographical feature of the Park is the Manitoba Escarpment, which rises 300 m above the Manitoba Plain to the east. Several gorges, old beach ridges and outwash plains occur along the eastern slopes of the Escarpment. ' Q. macrocarpa' stands occur as monodominant stands do these xeric sites, or in mixed stands on more mesic substrates. Baseline information including the population dynamics, floristic composition, community structure and vegetation-environment relationships of 'Q. macrocarpa' stands was collected. A total of 191 sample plots were enumerated over two field seasons (1998-1999). Species abundance data and statistical analysis were used to classify the plots into three stand types based on a complex moisture gradient. Organic matter, exposure, percent sand, conductivity, and slope were also strong determinants of stand and community structure. Recruitment of 'Q. macrocarpa' was highest in more open stands in xeric sites and lowest in closed stands due to low light conditions.