Roni et al 2015 wood placement summary

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Roni, P., Beechie, T., Pess, G. and Hanson, K., 2015. Wood placement in river restoration: fact, fiction, and future direction. Canadian Journal of Fisheries and Aquatic Sciences, 72(3), pp.466-478.


  • Describes the long history and extent of wood placement, including under the CCC during the depression of the 1930's.
  • The focus of placement has been to create pools and protective cover, resulting in documented improvement to trout numbers in Eastern US streams.
  • NW streams are higher energy, larger, steeper, and more dynamic. Concern over the failure rate of wood structures has led to construction of structures using whole trees to form jams to mimic natural accumulations of woody debris.
  • Removal of wood has led the public to be accustomed to rivers without wood, and wood can cause damage to bridges and levees, and may present a recreational risk.
  • Natural recruitment of wood varies based on stream order with debris flow in steep confined systems, tree fall in mid-order, and bank erosion in high-order systems (see Montgomery 1999 for process domain concept.)
  • Natural loss of wood also varies by stream order, with slow decay in low orders, and transport to sea at higher orders.
  • Resulting loading rates are highly variable and depend on vegetation and stream order, with higher levels of over 1000m3 per hectare in dense conifer forest.
  • Wood results in sediment storage, increase retention of organic matter and nutrients, island formation, decreased grain size, sediment sorting, increased spawning area, increased pool number, area and depth, and can change overall channel morphology, increased side channel formation, reduced bank erosion, and increased spread and retention of floodwaters.
  • Meta analysis of wood placement effectiveness indicates that asking the right questions is important for evaluating restoration through would placement.
  • Wood naturally occurred in most stream channels, failure rates of placement are relatively low, particularly when viewed from a reach scale, and positive physical and biological responses are reported by most studies.