Landscape Change Analysis for the Klamath-Siskiyou Ecoregion

Executive Summary

March 2001

We classified NALC (North American Landscape Characterization) imagery to forest- nonforest and examined forest change between 1972 and 1992 in the Klamath-Siskiyou ecoregion (U.S.A.) in relation to land ownership, elevation, and fifth field watersheds. We also analyzed changes in forest patterns by land ownership for three major river basins within the ecoregion (Eel, Klamath, and Rogue) using FRAGSTATS. Overall, forests covered 67.0% of the ecoregion in 1972 and 62.2% in 1992. Approximately 10.5% of the forest area was disturbed overall, translating into an annual rate of 0.53%. Although public lands accounted for a slightly higher total area of forest disturbance, private lands were cut at a slightly higher rate. Seventy-five percent of the total area of forest disturbance was in low or mid-elevation forests, but high elevation forests, making up the remaining 25%, were cut disproportionately high to their land area. Forest disturbance within fifth level watersheds averaged 13.2%, but reached as high as 93.2%. For the three river basins where spatial pattern of forest disturbance was analyzed, private lands were already more fragmented than public lands in 1972. Over the 20-year time period, forest fragmentation increased on all ownerships. Fragmentation rates on public lands were high for all basins especially the Rogue. Clearcut logging on private lands was generally in larger adjacent tracts, whereas cuts on public lands were generally smaller and more dispersed. Our results illustrate the importance of considering landscape change history when planning for effective biodiversity conservation in forested ecoregions and when formulating ecologically sustainable forest management strategies.

For more information, please contact Jim Strittholt .