Forest Landscape Changes in East Texas from 1974 to 2002

I.-K. Hung 1 , J. M. Williams 1 , J. C. Kroll 1 and D. R. Unger 2

College of Forestry, Stephen F. Austin State University (1)
Institute of Water and Flood Management, BUET, Dhaka-1000, Bangladesh (2)

Timber production has been one of the most important industries for East Texas since the mid 19th century. For years, timber has represented over one-third of all agricultural income in this region. In order to review forest landscape changes over time -- resulting from many years of management and investment -- historical satellite remote sensing data from 1974 to 2002 were used to determine landscape patterns and changes on four counties of East Texas; Angelina, Nacogdoches, San Augustine, and Shelby. Land cover was classified either as forest or non-forest and a thematic map generated on each of seven time stages. Landscape patches were identified on each thematic map and landscape metrics calculated, including patch size, aggregation of patches, and patch shape complexity etc. Results showed a decline of total forestland in the 1980s and a recovery in the 1990s. This observation coincided with historical information about large scale clear-cutting during this time. Mean patch size of forest showed a trend of increase, whereas that of non-forest was consistently decreasing over time. This reflects the decrease of forest patch shape complexity, while the patch shape of non-forest becomes more complex. The forest in East Texas plays an important role (presumably from intensive management) not only in local economy but also in the environment. Replanting efforts have created buffers between land development such as urban sprawl and ranching. Eventually, the forest maintains the overall landscape contagion while non-forest land-use is becoming more fragmented.

Keywords: landscape ecology, fragmentation, landscape metrics

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