Methods for fuzzy classification and accuracy assessment of historical aerial photographs for vegetation change analyses. Part II: Practical application

This paper is a presentation of the practical application of the algorithms developed in Part I of this series. It is based on the assessment of tree changes with respect to topography in a part of the Adulam Nature Reserve, Israel, between 1945 and 1996. The study is an input to ongoing ecological studies to determine the rate and pattern of tree invasion of plant species in the Adulam Nature Reserve. Datasets available for this study are images of the project site for the years 1945, 1956, 1965, 1967, 1980, 1984 and 1996. For the change detection process, a post classification image differencing method was adopted. In order to enhance the change detection and analysis processes as well as minimize errors, image differencing was applied to grid images generated from image classification products. Since ground data for the accuracy assessment of classification results were unavailable, a method of fuzzy classification and accuracy assessment of classification was employed. Results of this study show a significant general increase in percentage cover of trees in the study area between 1945 and 1996. A peak percentage range of tree cover (35-36%) was observed between 1980 and 1984. Also, a statistically significant interaction between topography and rate of change of tree cover was observed.