Forest Image

Riparian Ecosystem Management Study Design

Riparian Ecosystem Management Study (REMS) is organized around a before-after-control-impact (BACI) design, with three phases:

  1. Pre-logging (1-2 summers).
  2. Logging (lasting a few months).
  3. Post-logging (2 or more summers).

The full study examines 31 basins distributed across eight basin clusters. Clusters and basins studied were selected by the Department of Natural Resources. Screening factors included:

  • Basins to be logged within two years.
  • Overstory of similar rotation age, logged only once previously (so called second growth).
  • Application of buffer treatments in a single logging operation.
  • Basin area low (i.e., generally < 7 ha) and channel length short (i.e., generally < 400 m).
  • Clusters of basins distributed equitable between sub-regions.
  • Typical regional side slope elevation band.

Where possible, basins being logged were clustered within a single timber sale, with reference basins in  an adjacent sale.  Logging was excluded from the Riparian Management Zone (RMZ), a strip adjacent to streams, typically buffed for mainstems and other fish-bearing waters.


Each study basin was assigned one of four levels of forest retention.


After Bigley, 2002 (DNR REMS development)

  1. Reference:  no logging in basin.

  2. Continuous buffer:  minium 30 feet wide, beginning at upslope edge of RMZ and extending upchannel to beyond the headwall.  Remainder of basin clearcut.

  3. Patch-cut buffer:  varying percentages (~10-60%) of riparian forest adjacent to the channel retained.  Remainder of basin clearcut.

  4. Clearcut:  all merchantable trees removed but with 30-foot equipment exclusion zone adjacent to channel.

Based on locations of reference basins, width of RMZ, protection of unstable slopes and wetlands, and harvest objectives, not all forest retention levels were replicated in each cluster.

Basin Descriptors

Ecology’s role in REMS is part of a broader, integrated study undertaken with DNR and the U.S.D.A. Forest Service (hereafter, USFS). Each agency concentrates on specific tasks and acts as its own data steward.  Specific questions about data sets or methodology should thus be directed to the relevant agency. Note:  Due to constraints, Ecology’s role is confined to six basin clusters (21 basins total).

 See the list of REMS tasks, along with the contact information for the respective agencies responsible for data collection and analysis.