Date of Award

January 2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geography & Geographic Information Science

First Advisor

Bradley C. Rundquist

Abstract

Grand Forks County, ND, has one of the highest concentrations of shelterbelts in the World (Knutson 2011). As these trees aged and reached their expected lifespans, the quality of the shelterbelts has decreased and many have been removed. The rate of tree removal is thought to be increasing, with few shelterbelts being replanted. This raises concerns over possible increases in soil erosion caused by wind, such as was experienced in the 1930s. Using remotely sensed imagery and GIS, historic and recent shelterbelt densities can be measured and changes over time can be recorded. Geographic object-based image analysis (GEOBIA) can be used to automate shelterbelt density measurements on modern 4-band imagery, while older panchromatic imagery requires manual digitization. The wind erodibility index, soil pH, and surface geology were examined as possible agricultural driving factors.

Shelterbelt density was found to increase between the historic 1962 imagery and the modern 2014 imagery. A third image taken in 1995-1997 was used to confirm the finding. Shelterbelts in the county appear to have a spatial arrangement that stays fairly consistent between 1962 and 2014, with soil pH and surface geology helping to explain the observed spatial pattern.

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