Where’d the wood go? The importance of wood in rivers and how we can learn to appreciate it

Guest Post by Emily Iskin, 2022-2023 Sustainability Leadership Fellow, and Ph.D. Candidate in the Department of Geosciences at Colorado State University

Around the globe, rivers were once full of wood. Where did it go? And why does it matter that it’s gone? Wood was historically removed from rivers for transportation (think the Mississippi River), infrastructure, and safety, but we now know that the removal of wood can significantly alter river corridors.

Fig. 1: Floodplain wood on the banks of the Embarrass River, Illinois. © 2022 Emily Iskin Art & Design.

 Wood provides many benefits and performs many functions in river ecosystems. In relation to flows, wood stores water, sediment, and organic matter behind logjams1; acts as carbon storage2 (Fig. 1); and increases the exchange of water, gases, and nutrients between the stream and the streambed3–5 and between the stream and the floodplain6–8. Wood can create habitat for plants9–11 (Fig. 2) and animals12–14; and increase overall complexity and heterogeneity of the river corridor15–18. We also know that wood is stored for a period of time in streams, but that an essential function of wood is movement through river systems at varying rates19,20 to its final destinations of lakes and oceans21.

Fig. 2: Instream wood in the Hoh River, Washington, providing habitat for vegetation. © 2021 Emily Iskin Art & Design.

The fields of fluvial geomorphology, riparian ecology, stream biology, and river restoration have recognized the value of wood in rivers for decades. Barriers that need to be decreased or reversed for successful wood reintroduction include deforestation that reduces the historical source of wood, active removal of wood that naturally falls into rivers, fear of mobile wood damaging infrastructure such as bridges, and hesitancy around the local effects of wood in streams such as local flooding and backwater rise near logjams. Overcoming these barriers will require examples of successful reforestation near streams, a shift in policy and responsibility regarding where wood is put in and where it ends up, and eventual room for rivers to inundate their floodplains and move without restriction.

Restoration of natural sources of wood and reintroduction of wood to rivers is gaining traction with communities large and small, but success will require shifting the negative public perception22,23. This challenge can be overcome through increasing awareness and education around the benefits of wood in streams, starting with effective signs and displays in national and state parks and local river recreation sites. Shifting the view of what a natural stream looks like and increasing public acceptance of wood’s place in these systems is going to increase the speed of restoration and effectiveness of wood in streams. Without public support, the task of restoring wood to river systems is already dead in the water.


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