Collins et al 2012 floodplain large wood cycle

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Collins, B.D., Montgomery, D.R., Fetherston, K.L. and Abbe, T.B., 2012. The floodplain large-wood cycle hypothesis: A mechanism for the physical and biotic structuring of temperate forested alluvial valleys in the North Pacific coastal ecoregion. Geomorphology, 139, pp.460-470.


  • Presents evidence supporting an "alternate stable state" hypothesis driven by the introduction of large stable log jams which depend on large key pieces of wood.
  • Absence of key pieces results in rapid turnover of floodplain surfaces (see Naiman et al 2009) which prevents production of key pieces (a reinforcing feedback loop).
  • Presence of key pieces allows for formation of floodplain islands, which reduces the rate of surface turnover, allowing for production of more keypieces (also a reinforcing feedback loop).
  • The presence or absence of key pieces and associated hard points can result in a shift in state from an anastomosing structure, or a braided or meandering structure (depending on factors such as slope and sediment budget.)
  • Under this theory, construction of Engineered Log Jams is in part a temporary reestablishment of hardpoints within a floodplain to push the river from one state to another state .
    • What is the lifespan of an ELJ and does that match the necessary function of a floodplain hard point?