1. Stand Structure and Ecological Restoration Charles W. Denton Ecological Restoration Institute John D. Bailey, Associate Professor of Forestry, Associate Professor of Forestry, Northern Arizona University, School of Forestry

2. Today’s Topics “Stand Dynamics” and the role of disturbance Single vs. multiple species Density and basal area –Even-aged stands –Multi-aged stands Special stand structures, living and dead Scaling up spatially Temporal variation and planning

3. Stand Dynamics Regulates: –Age and size distribution = even-aged vs. multi-aged stands –Vertical canopy structure/layers –Horizontal arrangement issues Four basic stages: Stand initiation –Stand replacing event, growing space Stem exclusion (“thinning”) –Self-thinning, low diversity, zero g.s. Understory reinitiation (“transition”) - shifting mosaic Old-growth

4. Presettlement Age Distribution in Northern Arizona Mast et al. 1999 180

5. Single vs. Multiple Species Mix and ratios based on: Disturbance type (e.g., fire) Shade tolerance –Initiation vs. transition Management preferences Spatial arrangement issues

6. Presettlement Ponderosa Pine Spatial Distribution Gus Pearson Natural Area Covington et. al., 1997 width of circle indicates age

7. Current conditions at the Gus Pearson Restoration site

8. Diameter Distribution Fort Valley, Arizona

9. S10S9 Kathy Smith’s thesis 1999

10. Interpreting Density Measures Trees per acre –Little use in multi-aged BA and SDI –Workable, particularly at extremes Canopy closure –Aerial fuels and growing space

11. Hypothetical Results of a BDQ 14-50-1.2 Treatment S9-10 Before Treatment S9-10 After Treatment

12. Implications Multi-aged is ‘historically accurate’ Group selection created “clumpiness” relative to individual-tree selection Must revisit the sites regularly - the 1919 cohort is now a real problem VSS distribution Mistletoe does not have to be a concern

15. Special Structural Elements Large, old trees –Not “old-growth” trees Vigorous lower and mid- canopy trees –True advantage of multi-aged Snags and aerial dead wood –Wildlife habitat value Downed, coarse woody debris –Ecosystem value ALL have their limits!

16. UnburnedBurned ControlThinned Thinned and Burned Wildfire Disturbance Gradient STIFH Treatment Gradient

17. Forest Health “Indicators” Overstory structure and growth/vigor Fuel loading Understory composition Insect diversity Soil nitrogen Ectomycorrhizal fungi Wildlife use

18. Scaling up spatially welcome to “ecosystem management” Three fundamental scales for diversity: – Within stand – Among stands – Landscapes, watersheds and fragmentation Stand inequality is good ALL have their role!

20. Temporal Scales Trees grow Disturbance happens Trees grow Stands change somewhat predictably given stand dynamics, but often unpredictably Trees grow …Adaptive Management!

21. Fire mortality 1999 data collection

22. REGENERATION Adequate in most decades –seed tree density and production –seedbed and germination –mortality, particularly with fire More likely TOO MUCH Some decades may be insufficient, but that’s OK

23. Concluding Remarks: Structure and Restoration It’s ALL about structure Multi-aged is often the way, but more complicated Promote small trees, too Spatial heterogeneity Diversity at all three scales