Browsing by Author "Trumper, Matthew"
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Item Green Ash 2001 Flood Event at Mississippi River Floodplain(2024-04) Danz, Jeremy; Trumper, Matthew; Crawford, DanielWith the help of Professor Daniel Griffin, throughout the semester, I have been working with Green Ash tree samples. My goal has been to examine and identify whether or not a flood in the Mississippi River floodplain in southern Minnesota in early 2001 shows a significant difference in the early wood vessel size leading to significantly smaller annual rings in that year. To get the early wood vessel size, for each sample, the images were retrieved using a high powered robotic GigaMacro camera where many images were taken and then stitched together. Once a final composite image had been created, it was uploaded to DendroElevator where it was measured for the five years preceding the 2001 flood event and the five years following the event using a tool in DendroElevator which is a database of tree core samples to gain a larger picture of how the flood affected the area.Item Multi-Scale Topographic Influences on Tree Growth: A Case Study of Quercus lobata in the Tehachapi Mountains, California(2022-12) Trumper, MatthewComplex topography can facilitate climatic and hydrologic microenvironments that buffer plants against climate change and extreme drought. However, the extent to which topographic position mediates tree growth response to climate remains an open question. Dendrochronology, the study of precisely dated tree rings, has been a valuable tool for assessing tree growth response to climate variability across topographic gradients. In this study, six new tree-ring chronologies were developed from valley oak (Quercus lobata), a long-lived, endemic species in California. Trees were sampled growing in upland and riparian hillslope positions along a 1,300-meter (4,265-feet) elevational transect in the Tehachapi Mountains of California to understand how topography acts as a mediating factor on tree growth and drought sensitivity. Valley oaks are thought to be highly dependent on groundwater, so I hypothesized that higher groundwater availability at the riparian sites would mediate growth sensitivity to drought. Results showed that tree growth patterns and drought sensitivity varied substantially in association with hillslope position and elevation. Valley oak radial growth showed a consistently weaker response to precipitation at riparian sites, supporting my hypothesis. The influence of hillslope position on drought sensitivity varied with elevation, such that the riparian buffering effect was strongest at the low elevation sites and weaker at higher elevations. At upland sites, precipitation and tree growth covaried on annual to decadal time scales, depending on elevation. The strong topographic influence on valley oak growth and drought sensitivity observed here has implications for climate refugia planning and paleohydrology using this species.