Applying Density Management to Develop Late Successional Features Klaus J. Puettmann Oregon State University

Studies StudyLocation Overstory Species Age at thinning% max SDIRemarks ODF OR Coast RangeD-fir5-20NA Standard plantations Newton ColeCorvallisD-fir5020 – 40 Thinned previously Blodgett W. Hemlock5020 – 35 YSTDSWillamette NFD-fir4020 – 60 WildcatSuislaw NFD-fir3010 – 55 DMSBLMD-fir LindhWillamette NFD-fir PCT

Late successional features:  Overstory cover  Canopy layers  Large, dominant trees  Tree species mixtures, including hardwoods  Amount and composition of understory vegetation  Conifer regeneration  Spatial variability

Late successional features:  Overstory cover  Canopy layers  Large, dominant trees  Tree species mixtures, including hardwoods  Amount and composition of understory vegetation  Conifer regeneration  Spatial variability

Overstory Cover Willamette National Forest: Douglas-firBeggs 2005

Overstory cover Newton and Cole 2004 McDonald Forest: Douglas-fir, previously thinned

Crown structures Suislaw National Forest: Douglas-fir Chan et al. 2005

Foliage Height Diversity Index 0 m 10 m 5 m 30 m 25 m 20 m 15 m 35 m << STAND 1STAND 3STAND 2

Foliage Height Diversity Index 3 to 5 years after thinning Beggs 2005

Impact of thinning on volume and on growth rate (i.e., slope of volume curve)

Acceleration of “dominant old-growth” trees: Diameter growth of largest 6 tpa Growth (cm / yr) Willamette National Forest Beggs 2005

Douglas-fir Golden chinquapin Hardwoods Control 14.0 (a)27.1 (a)36.1 (a) (12.3 – 15.8)(19.4 – 34.9)(28.4 – 43.8) Heavy 4.7 (b)7.8 (b)18.0 (b) (0.1 – 9.3)(-1.1 – 16.7)(8.9 – 27.0) Light 5.9 (b)15.1 (a) (b)15.3 (b) (3.1 – 8.8)(1.5 – 28.8)9.0 – 21.6 LtGaps 4.0 (b)4.4 (b)13.4 (b) (0.8 – 7.2)(-3.6 – 12.5)(7.0 – 19.7) Overstory Mortality (%) Mostly competition related Beggs 2005

Late successional features:  Overstory cover  Canopy layers  Large, dominant trees  Tree species mixtures, including hardwoods  Amount and composition of understory vegetation  Conifer regeneration  Spatial variability

Late successional features:  Overstory cover  Canopy layers  Large, dominant trees  Tree species mixtures, including hardwoods  Amount and composition of understory vegetation  Tree regeneration  Spatial variability

Seedling survival 8 growing seasons after thinning Adapted from Maas-Hebner et al FEM

Seedling survival after 8 growing seasons Adapted from Maas-Hebner et al FEM

Seedling survival Newton and Cole 2004 McDonald: Douglas-fir

Western Red Cedar Douglas-firGrand FirWestern Hemlock Total % Damaged Harvesting damage to regeneration McDonald Forest Newton and Cole 2004

Impact of light availability on seedling growth Maas-Hebner et al. 2005

Western Hemlock Newton and Cole 2004 Impact of overstory density

Effects of weed control Western hemlock Newton and Cole 2004 Blodgett

Variation in overstory cover when gaps in interspersed in thinned stands Frequency Overstory Cover (%) Beggs 2005

Conclusions  Different late-successional components require different management strategies  Tradeoffs in terms of stand growth  Overstory and understory conditions before thinning are good indicators of responses  Some flexibility in thinning intensities  Repeated entries likely required

Density management needs to be an integral part of managing for late successional habitat, but additional measures, (gaps, snag creation, or remnant trees) are also necessary

Questions