INTERACTIONS BETWEEN FOREST AND LANDSLIDE ACTIVITY ALONG NEW HIGHWAYSIN THE KUMAUN HIMALAYA

Forest cover and landslide activity were surveyed along two hill roads crossing steep hillsides in the Kumaun Himalaya. The Kilbury Road is cut through reserved forest (29 degrees 24'N 79 degrees 28'E, altitude 2100 m). The Almora Bypass crosses a suburban fringe (29 degrees 16'N 79 degrees 40'E, altitude 1650 m). Tree canopy cover upslope of the r oad cut was 56.8% along the Kilbury Road and 14.1% along the Almora By pass. Tree canopy cover downslope of the roadbed was 35.7% and 7.6% re spectively. Ground vegetation cover downslope of the road was also muc h reduced. In 1990 (and 1985), landslides affected 80.9% (76.5%) of th e roadcut in the forest and 42.5% (43.1%) along the suburban roadcut. Statistical correlation of forest cover and landslide attributes recor ded for each 200 m reach of roadbed demonstrate that, in the suburban case study, forest cover correlates positively with landslide activity -because forest survives mainly on sites which are too steep and unsta ble for development. However, in reserved forest, negative correlation s link forest cover and landslide activity. Correlation of the ratio b etween forest cover downslope and upslope of the road with environment al and landslide activity attributes produces little that is significa nt from the combined or Almora data sets. However, along the undevelop ed forest road, low ratios, indicating a greater proportional reductio n of tree cover downslope of the road, are significantly associated wi th steeper slopes, higher roadcuts, increased slumping onto the roadbe d, and increased undermining of the roadcut by landslide and erosional processes.