Rates and Processes of Bare Patch Denudation in the Subalpine Grassland of Mt. Halla* Taeho Kim** 1 710m 1 600m 85 2 38cm 2002 2004 2 39 2mm 19 6mm 131mm 0mm 4 10 11 6 7 100 Abstract Rates and processes of bare patch denudation were observed at Janggumokoreum(1,710m) and Minoruem(1,600m) in order to clarify some characteristics of turf exfoliation in the subalpine grassland of Mt. Halla. The bare patches have marginal terrace fronts with a maximum height of 85 cm. The terrace risers usually develop an overhanging edge 2 to 38 cm long that eventually hangs down and protects the riser beneath. The patches are largely covered with angular pebbles and cobbles. The mean rate of riser retreat for the period 2002-2004 is 39.2 mm, equivalent to 19.6 mm/yr. However, there is a disparity of the rate of riser retreat at individual sites. The maximum rate is 131 mm measured at Janggumokoreum patch while the minimum rate is 0 mm at Minoreum patch. The rate of riser retreat also varies with seasons. The thawing season of April exhibits a maximum rate of retreat. The freezing season of October and November and the rainy season of June and July show relatively high rates of retreat. Several processes such as frost action, aeolian deflation, rainwash, rainsplash and fauna activity cause the denudation of bare patches. In particular, the needle ice action which is combined with rainwash or deflation plays a primary role in turf exfoliation due to the diurnal freeze-thaw cycles occurred over 100 days, melted snow and strong wind in the subalpine zone of Mt. Halla. Rainwash is also an important contributing process in the rainy season because Mt. Halla 2004 04 2 70 76 2006 Associate Professor, Department of Geography Education, Cheju National University kimtaeho@cheju.ac.kr 657
has the highest precipitation in Korea. By contrast, rainsplash erosion has a minor effect on the bare patch denudation due to the overhanging edge of terrace risers. Recent increase in roe deer appears to be responsible for turf destruction. : turf exfoliation, frost action, deflation, rainwash, roe deer, riser retreat, subalpine grassland, Mt. Halla turf exfoliation Pérez 1992 deflation Sapper 1915 King 1971 Hastenrath and Wilkinson 1973 Troll 1973 1974 Pérez 1992 1997 Rost 1999 Grab 2002 2002 1 400m 1997 2000a 600m 70 5% 15 2000a 9 2% 5 1 13 cinder cone 4 2000b 658
1,710m 1,600m 7 1990 970m 9 7 1 400m 7 3 4 1 1 3 711 3 5 4 2 11 4 2000 3 356 5mm 8 9 631 0mm 443 5mm 7 575 5mm 100mm 11 1 1991 1985 1985 1 2 3 4 5 6 7 8 9 10 11 12 2 4 0 0 3 6 9 9 13 7 17 2 20 5 20 6 16 9 10 1 5 6 0 5 9 7 mm 85 7 111 3 150 8 361 2 410 2 273 0 575 7 631 0 443 5 103 5 102 0 108 7 3356 5 659
Sasa quelpaertensis 1 710m 1 600m 1 40cm 5mm 30cm 1 2 10cm 5 8 2 15 43 25 38 2002 9 29 10 1 2 1 400m 1 600m 1 700 1 800m 50m cm 660
70cm 4 solifluction lobe 67m 52m 5 15cm terracette 1m 7 6 26m 12m 3 10 28cm 4 2002 31 85cm Festuca ovina) Empetrum nigrum var. japonicum cm 661
2 38cm 70cm 40cm 1 6m 1 5m 2002 9 29 10 1 2002 12 5 2003 4 4 4 26 6 15 7 25 10 1 11 30 2004 5 5 6 18 8 2 10 1 2 2003 4 4 26 4 2 44 6mm 33 3mm 39 2mm 19 6mm 2003 4 4 6 15 9 5mm 4 662
131mm 4mm 88 5mm 0mm 2003 4 4 6 15 78mm 2 88 2004 3 26 11mm 12 4 6 2002 9 1mm 2003 13mm 2002 12 5 2003 4 26 17 7mm 2003 11 30 2004 5 5 16 2mm 40cm 2001 12 3 4 5 4 2003 4 5 1mm 10 12 2002 2mm 2003 2 5mm 2002 9 29 12 5 3 1mm 2003 10 1 11 30 3 8mm 2002 4 0mm 2003 2 5mm 2003 2 4mm 2004 4mm 2003 6 15 7 25 3 5mm 2004 6 18 8 2 3 4mm 1 1mm 5 1mm 8 9 Sapper 1915 Kim 1967 2003 0 58 100m 1999 663
1 710m 1 600m 105 101 3 7 4 11 15 0 King 1971 Hastenrath and Wilkinson 1973 Pérez 1992 Grab 2002 664
8 8 King 1971 Troll 1973 1915 Arnalds 2000 1997 2001 6 8 3 9 Pérez 1992 9 3m 60cm 2000 2 8 1 810m 7 16 7214 19 34 2000c rainsplash erosion 1 3 2 5mm 7 9 1cm 1981 10 1997 2001 665
38cm 4 11 rainwash sheet flow rill flow 1999 12 11 Hastenrath and Wilkinson 1973 Pérez 1992 Watanabe 1994 Rost 1999 1988 1980 0 138 ha 1 600m 0 38 ha 2001 13 16cm 10cm 5 12cm 13 Grab 2002 3 5 10 12 100 4 11 15 4 666
4 12 3 4 5 6 7 8 9 3 4 10 11 6 7 8 9 4 5 4 38cm 4 11 14 1 2 3 4 5 6 7 8 9 10 11 12 667
1 400 1 800m 1 710m 1 600m 2002 10 2004 9 2 85cm 2 38cm 2 44 6mm 33 3mm 39 2mm 19 6mm 131mm 0mm 4 10 11 6 7 100 2002 668
2000 2002 1 1 27 1999 34 385 393 1999 1985 41 45 1985 311 330 2001 36 233 246 2002 9 71 81 2002 1 101 113 1991 2000a 2000b 2000c 1997 1974 26 118 2001 110 355 361 1997 70 676 692 1990 41 527 537 1997 49 1 14 1981 Arnalds, O., 2000, The Icelandic rofabard soil erosion features, Earth Surface Processes and Landforms, 25, 17-28. Grab, S. W., 2002, Turf exfoliation in the High Drakensberg, southern Africa, Geografiska Annaler, 84A, 39-50. Hastenrath, S. and Wilkinson, J., 1973, A contribution to the periglacial morphology of Lesotho, southern Africa, Biuletyn Peryglacjalny, 22, 157-165. Kim, D. J., 1967, Die dreidimensionale Verteilung der Strukturboden auf Island in ihrerklimatichen Abhangigkeit, Diss. Bonn, Math. Nat. Fak., 227S. King, R. B., 1971, Vegetation destruction in the sub-alpine and alpine zones of the Cairngorm Mountains, Scottish Geographical Magazine, 87, 103-115. Pérez, F. L., 1992, Processes of turf exfoliation(rasenabschalung) in the high Venezuelan Andes, Zeit fur Geomorphologie, N.F., Suppl. Bd., 36, 81-106. Rost, K. T., 1999, Observations on deforestation and alpine turf destruction in the central Wutai Mountains, Shanxi Province, China, Mountain Research and Development, 19, 31-40. Sapper, K., 1915, Rasenabschalung, Geographische Zeitschrift, 21, 105-109. Troll, C., 1973, Rasenabschalung(Turf Exfoliation) als periglaziales Phanomen der subpolaren Zonen und der Hochgebirge, Zeit fur Geomorphologie, N.F., Suppl. Bd., 17, 1-32. Watanabe, T., 1994, Soil erosion on yak-grazing steps in the Langtang Himal, Nepal, Mountain Research and Development, 14, 171-179. 690 756 66 kimtaeho@cheju.ac.kr064 754 3235 Correspondence Taeho Kim, Department of Geography Education, Cheju National University, Jejudaehak-Road, Jeju 690-756, Korea (email kimtaeho@cheju.ac.kr, phone +82-64-754-3235) 669