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Summary & Conclusions

 

Other LULC Change in Carroll County areas:

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Chapter 6 - Summary & Conclusions

A Brief Project Reprise  |  Conclusion from The Analysis  |  Limitations of The Study  |  Strategies for Further Study  |  Land Use & Land Cover Dynamics  |  A Land Ethic

A Brief Project Reprise

The basis of this research comprises the multitemporal classification of Landsat Thematic Mapper satellite imagery to detect, delineate, and map the conversion of forests to pastures in Carroll County, Arkansas, 1984 - 1999. Thus, the aim of this research was to produce both current and past land use and land cover maps of Carroll County from recent and historic satellite imagery spanning the period of study to detect and map this land conversion; in addition, compile a land suitability assessment of the areas of forest clearing based upon slope, erodibility, and land productivity classifications.

The creation of a 1999 land use and land cover map for Carroll County was derived utilizing standardized digital remote sensing classification techniques. The classification employed three multitemporal Landsat scenes dated, May 7, 1999, October 6, 1999, and December 25, 1999. A hierarchical level II land use and land cover classification comprised of three urban classes, pasture, deciduous forest, coniferous forest, perennial water, and barren land classes was incorporated in the 1999 land use and land cover map. Final classification accuracy was determined to be satisfactory or ‘good’ by means of employing standardized accuracy assessment measures, the error matrix and the kappa coefficient of agreement. An overall accuracy of 84.75%, an average accuracy of 87.95%, and a Kappa coefficient 0.75577 or 76% was achieved by comparison with ground truth data obtained from extensive GPS field surveys.

The process of change detection was employed by utilizing a previously documented, image differencing method by Maus et al (1992), Doak and Lackey (1993), and Green et al (1994). Specifically, this process entailed a Band 7 subtraction of the difference in the mean values between an October 6, 1999 Landsat image from the September 18, 1984 Landsat image, followed by a subsequent classification of the derived difference or change image. The land use and land cover change map, 1984 - 1999, was comprised of converted forest (new pasture), converted pasture (new forest), and no change classes. It was determined by visual analysis that this procedure demonstrated to be an excellent indicator of level I forest clearcuts and subsequent conversion to pastures. The detection of increases in vegetative cover associated with the regeneration of forests from fallow pastures was also visually discernable. This was an unexpected but pleasant discovery, although should be a logical deduction in the grand scheme of land use change. Other land use changes such as increased urbanization were beyond the scope of this study.

A 1984 land use and land cover map of Carroll County was produce by employing simple image-modeling techniques. Areas that were classified as experiencing no change were classified the same in 1984 as in 1999 while those areas that had experienced either change from forest to pasture or pasture to forest were classified accordingly in the 1984 land use and land cover map. This process was completed by employing image-modeling techniques with the utilization of logical ‘if’, ‘then’ statements. Although this straightforward approach did not reflect other potential land use changes, the 1984 land use and land cover map suitably reflected the extent of previously forested areas as well as previous pastures before being reverted to successional forest.