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.

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

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…

Ecology Common nameBasal area (ft 2 /ac)Trees/ acre Black Oak Scarlet Oak White Oak Shortleaf Pine8.021 Post Oak5.822 Pignut Hickory3.849 Black Hickory3.644 Mockernut Hickory3.456 Flowering Dogwood Black Gum % 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

Ecology

Mortality risk factors Species Red oak mortality 4X that of white oaks Crown class Int/supp 3X Dom/codom Decadal mortality (%) Species Crown class White oak, post oak Black oak, scarlet oak Intermediate suppressed Suppressed Dominant, codominant Dominant, codominant 5.3 Intermediate

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

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

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

Silvicultural practices

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

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 ); RBA = B-level stocking (Roach and Gingrich, 1968) Group openings

Harvest removals TreatmentLand areaClearcutThinnedVolume (thousand bd. ft.) Even-aged2,80211%15%2,454 Uneven-aged3, % 1 3,442 1 Includes both single-tree and group selection

Harvest removals

Effects Basal area (ft 2 /ac)Canopy cover (%) beforeafterbeforeafter Clearcut stands Thinned stands (EAM) Selection cutting units (UAM)

Diameter distributions

Regeneration

harvest

Regeneration harvest

Regeneration 9% 11% 15% 14%

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??

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

Regeneration

Regeneration—year 10

Percentage of oaks 24% 11% 3%

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

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