Dataset associated with: Large wood in small channels: a 20-year study of budgets and piece mobility in two redwood streams

Large wood (LW) influences geomorphic and ecological processes. However, most field datasets describing LW dynamics are conducted over the span of only a few years. We present a unique dataset from northern California, USA of LW volumes, inputs, and transport in two headwater streams, the North Fork and South Fork of Caspar Creek. We used data collected approximately every two years over a 20-year period to assess how LW budgets change over time between catchments with varying land-use histories, what factors strongly influence inputs from standing trees to the streams, and controls on LW piece entrainment and displacement length. We find that the South Fork, which experienced stream-side logging and instream wood removal in the 1970s, continues to have lower LW volumes (101-153 m3 km-1) compared to the North Fork (297-313 m3 km-1), which experienced logging in the 1980s but with buffer strips left near the channel. If current trends continue, it will likely take 100-200 years from the time of logging for the South Fork to reach North Fork instream wood volumes. We also show that wet windstorms and hillslope steepness are strongly associated with the LW piece inputs from standing trees. LW is relatively stable in the channel, with piece characteristics, the density of pieces surrounding a LW piece, and discharge metrics influencing LW entrainment and displacement lengths. Our dataset provides strong support to previously identified controls on LW dynamics in streams while also capturing variability over a 20-year period.