The Ecology and Management of Wood in World Rivers

Wood Storage and Mobility

Angela M. Gurnell


Abstract.—This paper considers wood storage and mobility in relation to four themes illustrated by both literature review and case studies.

• The first theme presents estimates of wood storage in relatively unmanaged river systems by using information derived from the open literature. More than 150 sets of observations of wood storage are synthesized. In this international data set, major contrasts are found according to tree species, stand age, and geographic setting. However, the identification of trends in wood storage characteristics from the data set is confounded by interdependency in potential explanatory variables.
• The above analyses provide a context for the second theme, an examination of some of the factors that influence wood storage within river reaches. A number of influences are discussed, including the characteristics of the wood; the size and morphology of the river channel; a range of climatic, hydrologic, and geomorphic processes; and the nature of wood management.
• The aggregate effect of these influences is not only variability in the amount of wood stored in river reaches but also variability in its mode of storage, which forms the third theme of this paper.
• The amount and mode of wood storage are a product of the interaction between wood supply, transport, and retention characteristics of river reaches. The fourth theme of the paper is the presentation of two case studies that illustrate wood anchorage and mobility within rivers of different size.