More than 300 landslides and debris flows were triggered by an October 1993 storm on Prince of Wales Island, southeast Alaska. Initiation, runout, and deposition patterns of landslides that occurred within clearcuts, second-growth, and oldgrowth forests were examined. Blowdown and snags, associated with cedar decline and "normal" rates of mortality, were found adjacent to at least 75 percent of all failures regardless of land use.Nearly 50 percent of the landslides within clearcuts occurred within one year following timber harvest; more than 70 percent of these sites had hydrophytic vegetation directly above failures. In following the runout paths of failures, significantly more erosion per unit area occurred within clearcuts than in old-growth forests on slopes with gradients from 9 to 28 (16 to 54 percent). Runout length, controlled by hillslope position within deglaciated valleys, was typically longer in old-growth forests than in second growth and clearcuts (median values were 334, 201, and 153 m, respectively). Most landslides and debris flows deposited in first-and second-order channels before reaching the main stem channels used by anadromous fish. Slide deposits in old-growth forests were composed of a higher proportion of woody debris than deposits derived from slides in second growth or clearcuts. (KEY TERMS: landslides; debris flows; land use planning; erosion and deposition; woody debris; deglaciated valleys; Alaska; anadromous fish.)1Paper No.

The relative importance of suspended (>0.45 µm) and organic colloidal (<0.45 µm) matter in the transport of pesticide through and across a soil was studied by monitoring suspended and colloidal matter from lysimeters over a winter (1994–1995) and relating it to the leaching of pesticides. The major results were: (i) The organic colloidal matter and suspended sediment appeared at different times in the leachate. (ii) The suspended sediment was enriched in total organic carbon (TOC). (iii) The leaching of pesticide occurred largely in first few samples following rainfall, coinciding with the occurrence of the colloidal matter. (iv) Modelling the distribution of pesticide between the colloids, suspended matter, and pure solution suggests that negligible amounts of isoproturon are carried on suspended sediment and the organic colloids are more important. The importance of organic colloids may be even more significant for compounds more hydrophobic than those studied here: this has implications for the management of soils and pesticides in relation to the release of organic colloids into solution.

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Level-line surveys at a number of sites on the Antarctic Peninsula since the early 1970s have shown a lowering of the ice surface elevation in areas where the climate is warm enough for melting to occur during summer. Results are presented here from annual surveys on the ice ramp at Rothcra Point. Over an 8 year period, a large proportion of the ramp shows a generally steady reduction in surface elevation. The uppermost part of the ramp shows no clear trend. The ice ramp has suffered a mean rate ofsurfaee lowering of 0.32 ma−1 w.e. over the period of the surveys, which is similar to that seen at other sites on the Antarctic Peninsula. Measured ice velocities on the ramp are low, so the surface lowering can be attributed directly to changes in surface mass balance. The Surveys coincide with a period of long-term increase in temperature and ablation seen in meteorological records. Comparison of the observed surface lowering with temperature data shows a good agreement, and we conclude that increasing air temperatures in the region will raise ablation and increase the recession rate of the ice ramp.