Working with wood in rivers in the Western United States

Recognition of the important physical and ecological roles played by large wood in channels and on floodplains has grown substantially during recent decades. Although large wood continues to be routinely removed from many river corridors worldwide, the practice of wood reintroduction has spread across the United States, the United Kingdom and western Europe, Australia, and New Zealand. The state-of-science regarding working with wood in rivers was discussed during a workshop held in Colorado, USA, in September 2022 with 40 participants who are scientists and practitioners from across the USA, UK, Europe, and Japan. The objectives of this paper are to present the findings from the workshop; summarize two case studies of wood in river restoration in the western United States; and provide suggestions for advancing the practice of wood in river management. We summarize the workshop results based on participant judgements and recommendations with respect to: (i) limitations and key barriers to using wood, which reflect perceptions and practicalities; (ii) gaps in the use of large wood in river management; (iii) scenarios in which wood is generally used effectively; and (iv) scenarios in which wood is generally not used effectively. The case studies illustrate the importance of the local geomorphic context, the configuration complexity of the wood, and the potential for modification of river corridor morphology to enhance desired benefits. Moving forward, we stress the importance of collaboration across disciplines and across communities of research scientists, practitioners, regulators, and potential stakeholders; accounting for stakeholder perceptions of the use of large wood; and increasing non-scientist access to the latest state-of-science knowledge.