Trees and wood: working with natural river processes

A history of land clearance and riparian tree and wood management has resulted in limited riparian woodland and wood along British rivers. However, river management approaches are now being promoted that ‘work with natural processes’ to reduce flood risk through measures intended to restore, protect and emulate the natural function of catchments, rivers, estuaries and coasts. Wood has started to be reintroduced into river channels during river restoration and natural flood management activities, but this needs to be undertaken using appropriate quantities, locations and designs that mimic natural tree‐wood features. This paper reviews the knowledge that is needed to support wood reintroduction activities including (i) the characteristics of the riparian tree species and wood that are present; (ii) the importance of river size relative to that of trees and wood pieces; and (iii) the way trees, wood and geomorphic processes interact across rivers and floodplains of different energy and style.