Use of dendroanalysis to study environmental change in three unique geological/ecological settings

The advent of the twenty-first century has coincided with a period of relatively rapid environmental change. Most noticeable have been changes in environmental chemistry, both at the regional and local scale, which have occurred at rates observable on a human time scale. This study examines the growing use of dendrochronological techniques to assess changes in environmental chemistry, and contributes to the understanding of the way in which elements are stored within the woody tissue of individual tree species and to the assessment of the effectiveness of different dendroanalytical techniques to identify changes in environmental chemistry. In the first section, tree cores taken from an endemic conifer species, Araucaria laubenfelsii, growing in ultramafic soils on Mont Do, New Caledonia are analyzed using X-ray spectrometry. In the second section, the potential of using dendroanalysis for identifying areas at risk for forest dieback is evaluated. In particular, methodologies which detect and interpret changes in elemental chemistry in the woody tissue and link those changes to fluctuations in the environment are examined through a study of sugar maple trees growing at the deciduous forest-boreal forest ecotone in Lake Superior Provincial Park (LSPP), Ontario, Canada. In the final section, tree cores taken from trees growing along a gradient of environmental pollution in northcentral Illinois are analyzed using X-ray spectrometry to assess the feasibility of recreating the path of a pollutant containing heavy metals as it migrated over time through a karst landscape.; Overall, the results of the three studies indicate that dendroanalysis can be an effective methodology for analyzing spatial and temporal changes in environmental chemistry. Analysis of the cores taken from Araucaria laubenfelsii suggests that this species tolerates the relatively high concentrations of Ni within the ultramafic soils on Mont Do, and that topographic position, rather than community development, has greater influence in determining amounts of Ni uptake. In addition, differences in nutrient and heavy metal availability in the soils of the maquis and rain forest appear to be reflected in the woody tissue of the individuals growing within those communities. The preliminary findings of the study conducted at LSPP are consistent with those of other studies conducted in southeastern Ontario and northeastern United States: acidification of the soils appears to be linked with a decline in the growth of Acer saccharum in the forests of these regions. And finally, preliminary results at the Acme site indicate that pollutants have been stored in the woody tissue of Acer negundo growing down-gradient from the initial site of contamination.*; *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Microsoft Office.