The root systems of forest trees will be studied in sites where the aboveground portions of the trees have been damaged. Central questions of the research are: 1) Are "root gaps" formed at the same time as "canopy gaps" are formed?; and 2) What processes are involved in "root gap" formation and closure? A lodgepole pine ( Pinus contorta ) forest in the Medicine Bow Mountains of Wyoming will serve as the study site. Disturbance patches of various sizes will be created in the forest by cutting down and removing aboveground plant parts. The activity of fine roots and ectomycorrhiza will be measured using two different techniques . the screen intercept method and the sequential coring method. Root graphs and mycorrhizal links will be studied through careful field excavation for the former and laboratory dissection of soil cores for the latter. Finally changes in nitrogen mineralization and nitrification in the gaps will be studied by lysimetry and buried bag incubations. This research will expand our understanding of the biotic responses of forest systems to disturbance. Research on belowground components of forest ecosystems is rare and research on belowground components of disturbed forests even rarer. Yet we know that this research is needed for the development of predictive models that consider the effects of various kinds of disturbance on forest ecosystem function, including the forest's ability to act as a "filters" in watersheds that supply drinking water. Dr. Knight and his colleagues at the University of Wyoming are experts on production and nutrient cycling in the forests of the Rocky Mountain area. The institutional support available to them is very good.
