Conditions that maximize floodplain downed wood volumes: a comparison across three biomes

Floodplain downed wood can provide important habitat for aquatic, riparian, and terrestrial organisms. This wood, which can function as both a storage area and source for large wood in river channels, can also be a significant organic carbon stock in river-floodplain ecosystems. We present data on downed wood volumes for different floodplain vegetation communities in the central Yukon River Basin in interior Alaska. We measured downed wood volume per unit floodplain area and wood decay characteristics within four distinct floodplain vegetation communities, and equate downed wood volumes per unit area to total organic carbon per unit area. Preliminary results suggest that downed wood volumes are greatest in disturbed white spruce forests, compared to undisturbed white spruce, deciduous forests, and black spruce woody wetlands. Disturbances contributing to large wood volumes include fire, wind, and ice jam floods. We also compare wood volumes in interior Alaska to downed wood volumes in other unmanaged floodplain vegetation communities, including a subtropical lowland alluvial river-floodplain and a semi-arid mountainous river-floodplain. These three datasets provide comparisons of unmanaged riparian forests across diverse climatic settings and highlight the climatic conditions and biomes that result in substantial downed wood and organic carbon storage in floodplain environments.