Effects of Silvicultural Practices on Woody Vegetation

1. Effects of Silvicultural Practices on Woody Vegetation John Kabrick, Steve Shifley, and Dan Dey – USDA Forest Service Northern Research Station Randy Jensen, Mike Wallendorf, and David Gwaze –Missouri Department of Conservation David Larsen—Univ. of Missouri Zhaofei Fan—Mississippi State Univ. Eric Zenner—The Pennsylvania State Univ.

2. Questions of interest • Ecology of oak-dominated ecosystems • Composition • Productivity • Stand dynamics • Factors affecting tree mortality and survival • Emphasis on oak decline • Effects of silviculture on composition and structure • Effectiveness of regeneration methods

3. Woody data • 648 permanent vegetation plots • ½-acre: trees ≥ 4.5 in. dbh (tagged) • Four 1/20-acre: ≥ 1.5 to 4.5 dbh • Four 1/100-acre: ≥ 3.3 ft tall to 1.5 in. dbh • Inventoried every three years • Additional measurements including site index, height growth, crown development and dieback, presence of cavities and dens, insect pests…

4. Ecology -- 71% of basal area: black oak, scarlet oak, white oak, and post oak --1% of basal area: other oaks, incl. chinkapin oak, blackjack oak, Shumard oak, and northern red oak

5. Ecology

6. Ecology

7. Ecology

8. Mortality risk factors • Species • Red oak mortality 4X that of white oaks • Crown class • Int/supp 3X Dom/codom Decadal mortality (%) 13.9 Black oak, scarlet oak White oak, post oak Species 20.8 5.5 Intermediate suppressed Suppressed Dominant, codominant Crown class Crown class 13.0 2.3 38.3 Dominant, codominant Intermediate 14.2 5.3

9. Black oak Scarlet oak Mortality risk factors Mortality probability after 3 growing seasons • Crown condition • Healthy crowns: low mortality • DBH • Large trees: low mortality

10. Mortality risk factors Red oaks Initial abundance mortality Site factors are indirectly involved

11. Mortality risk factors • Oak borer attacks • Positively correlated to crown dieback • However, not correlated to oak mortality

12. Silvicultural practices

13. Even-aged management • 10% designated as “old growth” • Regeneration with clearcutting with reserves (10 to 15% of site per entry) • Intermediate tending (thinning, improvement cutting) • 100-year rotation, 15-year re-entry clearcuts

14. Uneven-aged management • 10% designated as “old growth” • Regeneration and tending with single-tree and group selection (5%) (Law and Lorimer, 1989) • Target q-value = 1.5 (range 1.3-1.7); RBA = B-level stocking (Roach and Gingrich, 1968) Group openings

15. Harvest removals 1Includes both single-tree and group selection

16. Harvest removals

17. Effects

18. Diameter distributions

19. Regeneration

20. Regeneration harvest

21. Regeneration harvest

22. Regeneration 14% 15% 11% 9%

23. Findings… • Clearcutting increased white oak and red oak regeneration and recruitment • Single-tree and single-tree + group selection increased regeneration of white oaks • Red oaks may be in trouble! • Oaks were a small proportion of the reproduction • Shortleaf pine??

24. Site interactions North- and northeast-facing South- and southwest-facing 4 Pro. RO/UG Backslopes 3 Exp. RO/UG Backslopes 6 Pro. LG/EM Backslopes 5 Exp. LG/EM Backslopes

25. Regeneration

26. Regeneration—year 10

27. Regeneration—year 10

28. Regeneration—year 10

29. Percentage of oaks 3% 24% 11% 24%

30. Findings… • Oak reproduction decreased with increasing site quality • Red oaks affected more than white oaks • “Intrinsic accumulators” vs. “recalcitrant accumulators” • Density of competitors and other species increased with increasing site quality and harvest intensity

31. Acknowledgments Support was provided by the Missouri Department of Conservation, the USDA Forest Service Northern Research Station, and the University of Missouri