1. Over 80 years Late-successional Old-growth Raymond Davis Monitoring Lead Older Forests and Spotted Owls (Northwest Forest Plan Area) Defining Older Forests

2. Early 1900s – Relative terms like “old-growth, large second growth, and second growth”. Differentiated slower growing older forests from the faster growing younger forests. A general sense of stand age, but largely based on diameter at breast height (DBH) of the largest dominant and co-dominant live trees. 1980s – Old-growth is best perceived as, “a stage of forest development characterized by more diversity of structure and function than that found in younger successional stages.” Chief’s Memo (1989) – Old-growth is usually distinguished by the presence of larger, older trees and structural attributes such as multiple canopy layers, decadence in the form of standing dead trees (snags), and accumulations of fallen trees (down wood). Interim Definitions (1992, 1993) - Provided discrete classifications based on minimum amounts of old-growth elements such as snags and logs. Related these things to stand age (usu. 150 to 240 years). Defining Older Forests - History

3. FEMAT and the Northwest Forest Plan (1993) – Mature phase of stand development begins around 80 years and is characterized by relatively large live and dead trees, although multiple canopy layers may not yet be well developed. Maturation stage = 80-140yr Transition stage = 150-250yr Franklin and Johnson (2013) – Used three different stand ages that might be declared “old” – 80, 120, and 160 years. Part of the social dialogue and intensely debated. BLM Western Oregon Plan Revision (2015) – Older (mature) and more structurally complex multi-layered conifer forests (80, 120, 140, 160, and 200 years). Defining Older Forests - History

4. Refine Definition for Older Forests Page 24 Existing definitions provided black and white answers, while in the real world structure and composition differ in gradients. Page 31 Need refined definitions or indices Need refined definitions or indices to assign plots and remotely sensed stands to a position along a continuum of older forest structure and composition.

5. Previous Monitoring Definition + Canopy Cover ≥10% Too simple and hard to interpret change Average DBH ≥20in

6. Old-Growth Forest Structure Elements +++ Large live trees Snags Down wood Diameter diversity “New” Monitoring Definition

7. Old-Growth Structure Index Stand age youngerolder 100 0 Spies and Franklin. 1988. Old growth and forest dynamics in the Douglas-fir region of western Oregon and Washington. Natural Areas Journal. 8: 190-201.

8. Old-Growth Structure Index Stand age youngerolder 100 0 Back to the Basic Elements

9. Large live tree density Stand age youngerolder 100 0 Large Trees

10. Large live tree density Stand age youngerolder 100 0 Large Trees plot data

11. Snag density Stand age youngerolder 100 0 Large Snags

12. Dead wood cover Stand age youngerolder 100 0 Fallen Trees

13. Diameter diversity index Stand age youngerolder 100 0 Multiple Canopy Layers

14. Old-Growth Structure Index Stand age youngerolder 100 0 Average Score of all Elements

15. Old-Growth Structure Index Stand age youngerolder 100 0 Selecting Mapping Thresholds

16. Old-Growth Structure Index Stand age youngerolder 100 0 Selecting Mapping Thresholds

17. Assigned plots and remotely sensed data to a position along a continuum of old forest structure and composition Older forests on federally managed lands in 1993

19. Scatter Graph of Western Hemlock Plots OGSI vs Stand Age

20. Scatter Graph of Western Hemlock Plots OGSI vs Stand Age <80yr with high OGSI

21. Scatter Graph of Western Hemlock Plots OGSI vs Stand Age <80yr with high OGSI >80yr with low OGSI

22. 25 th 75 th 5 th 50 th 95 th Stand Age OGSI Percentiles Graph of Western Hemlock Plots OGSI vs Stand Age

23. 25 th 75 th 5 th 50 th 95 th Stand Age OGSI Percentiles Graph of Western Hemlock Plots OGSI vs Stand Age

24. 25 th 75 th 5 th 50 th 95 th Stand Age OGSI Percentiles Graph of Western Hemlock Plots OGSI vs Stand Age

25. Stand Age OGSI Western Hemlock OGSI Elements vs Stand Age 80 yr 200 yr

26. Stand Age OGSI Grand Fir-White Fir OGSI Elements vs Stand Age 80 yr 200 yr

27. Stand Age Proportion of OGSI Western Hemlock OGSI Element Proportion vs Stand Age 80 yr 200 yr

28. Grand Fir-White Fir OGSI Element Proportion vs Stand Age Stand Age OGSI 80 yr 200 yr

29. WillametteValley UmpquaValley

30. WillametteValley UmpquaValley

31. Monitoring the Continuum

32. Acknowledgements Janet L. Ohmann, Robert E. Kennedy, Warren B. Cohen, Matthew J. Gregory, Zhiqiang Yang, Heather M. Roberts, Andrew N. Gray, and Thomas A. Spies o Justin Braaten (OSU) o Daniel Donato (WA DNR) o Andrew Merschel (OSU) o Vicente Monleon (USFS PNW) o Rob Pabst (OSU) o Matt Reilly (OSU) o Mike Simpson (USFS) o Andrew Yost (ODF) o Harold Zald (OSU) o Miles Hemstrom (INR) o Ashley Steele (USFS PNW) o Becky Gravenmier (USFS PNW)

33. Questions?