Structural Condition Class Descriptions

DecAID Successional Structure Classes (S-Classes) are based primarily on the size of trees that dominate the structure of the stand. Stands with few live trees (< 10% canopy cover) are classified as Early S-class, even though the few trees in these stands may be any age or size. The S-Classes correspond to the s-classes described by Haugo et al. (2015)

The S-Classes can be cross-walked to Structural Conditions from Chapter 3 in Wildlife-Habitat Relationships in Oregon and Washington (O'Neil et al. 2001). The exception is post-fire habitats which are not classified or described in O'Neil et al. 2001.

To view diagrams of example stands in the DecAID S-classes click on the links in that column below. Diagrams are from the Stand Visualization Simulator (SVS).

DecAID Successional Structure Class (S-Class) Definition s-class (Haugo et al. 2015) WHR Structural Conditions
Post-fire Recent (~ 10 years or less) stand replacing fire; with < 10% of live trees; high snag densities Early Seral N/A
Early

Stand Visualization Simulator (SVS) diagrams of example plots meeting the definition of Early Structural Conditions Class - tree stocking < 10% or tree stocking ≥ 10% and QMD 1-9 inches (2.5-24.9 cm).

 < 10% canopy cover of live trees OR dominated by seedlings, saplings, and/or poles 0-10 inches dbh (0-25 cm) Early Seral 1. Grass/Forb Open
2. Grass/Forb Closed
3. Shrub/seedling Open
4. Shrub/seedling Closed
Early < 10% canopy cover of live trees OR dominated by seedlings, saplings, and/or poles 0-10 inches dbh (0-25 cm) Early Seral
Mid Seral Open		 5. Sapling/Pole Open
Early < 10% canopy cover of live trees OR dominated by seedlings, saplings, and/or poles 0-10 inches dbh (0-25 cm) Early Seral
Mid Seral Open
Mid Seral Closed		 6. Sapling/Pole Moderate
Early < 10% canopy cover of live trees OR dominated by seedlings, saplings, and/or poles 0-10 inches dbh (0-25 cm) Early Seral
Mid Seral Closed		 7. Sapling/Pole Closed
Mid

Stand Visualization Simulator (SVS) diagrams of example plots meeting the definition of Mid Structural Conditions Class - tree stocking < 10% or tree stocking ≥ 10% and QMD 1-9 inches (2.5-24.9 cm).

 ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open 8. Small tree single story open
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open
Mid Seral Closed		 9. Small tree single story moderate
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Closed 10. Small tree single story closed
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open 11. Medium tree single story open
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open
Mid Seral Closed		 12. Medium tree single story moderate
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Closed 13. Medium tree single story closed
Late

Stand Visualization Simulator (SVS) diagrams of example plots meeting the definition of Late Structural Conditions Class - QMD > 20 inches (50 cm).

 ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Lateral Seral Open 14. Large tree single story open
Late ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Lateral Seral Open
Lateral Seral Closed		 15. Large tree single story moderate
Late ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Lateral Seral Closed 16. Large tree single story closed
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open 17. Small tree multi-story open
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open
Mid Seral Closed		 18. Small tree multi-story moderate
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Closed 19. Small tree multi-story closed
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open 20. Medium tree multi-story open
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Open
Mid Seral Closed		 21. Medium tree multi-story moderate
Mid ≥ 10% canopy cover of live trees AND dominated by small and/or medium size trees 10-20 inches dbh (25.0-50 cm) Mid Seral Closed 22. Medium tree multi-story closed
Late ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Late Seral Open 23. Large tree multi-story open
Late ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Late Seral Open Late Seral Closed 24. Large tree multi-story moderate
Late ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Late Seral Closed 25. Large tree multi-story closed
Late ≥ 10% canopy cover of live trees AND dominated by large and/or giant size trees ≥ 20 inches dbh (≥ 50 cm) Late Seral Open Late Seral Closed 26. Giant tree multi-story

1QMD= quadratic mean diameter

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