HR: 10:30h
AN: B52A-01    [Abstracts]
TI: Large wood dynamics and biophysical consequences for riparian forests: A comparison of an unconfined alluvial river in a temperate rainforest and a bedrock confined river in a semi-arid South African savanna.
AU: * Latterell, J J
EM: latterel@u.washington.edu
AF: University of Washington, School of Aquatic and Fishery Sciences Box 355020, Seattle, WA 98105 United States
AU: Pettit, N E
EM: npettit@u.washington.edu
AF: University of Washington, School of Aquatic and Fishery Sciences Box 355020, Seattle, WA 98105 United States
AU: Naiman, R J
EM: naiman@u.washington.edu
AF: University of Washington, School of Aquatic and Fishery Sciences Box 355020, Seattle, WA 98105 United States
AB: Large wood shapes the geomorphology and ecology of rivers. We determined the origin, distribution, and fate of large wood in two rivers from contrasting environments. The Queets is an unstable temperate, rainforest river running from the Olympic Mountains (USA) through a glacial valley with colossal trees. In most years, the channel erodes a variety of forested landforms which forms jams that sculpt habitats. Many are displaced in a few years. Remaining jams initiate landform development and forest renewal. Thus, wood is stockpiled in the floodplain where it may become buried. Channel movements recapture most logs within 50 years. In contrast, the Sabie is a perennial river running through a confined bedrock channel in a fire-prone semi-arid South African savanna. Riparian trees are relatively small and many sink in water. A recent flood (February 2000) devastated the riparian forest, introducing wood to the channel. Jams formed on toppled trees, transported logs, and bedrock outcrops. Many trees survived and resprouted. Jams facilitated the establishment of woody plant seedlings and the intrusion of fire into riparian areas. Sunken wood formed unique depositional features. The Queets and Sabie rivers are strikingly different systems. However, large wood appears to promote the renewal and development of complex riparian forests in both rivers.
DE: 1815 Erosion and sedimentation
DE: 1821 Floods
DE: 1851 Plant ecology
DE: 9305 Africa
DE: 9350 North America
SC: Biogeosciences [B]
MN: 2005 Joint Assembly