Applying Density Management to Develop Late Successional Features

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Applying Density Management to Develop Late
Successional Features

• Klaus J. Puettmann
• Oregon State University

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Studies
Study Location Overstory Species Age at thinning max SDI Remarks
ODF OR Coast Range D-fir 5-20 NA Standard plantations
NewtonCole Corvallis D-fir 50 20 40 Thinned previously
Blodgett W. Hemlock 50 20 35
YSTDS Willamette NF D-fir 40 20 60
Wildcat Suislaw NF D-fir 30 10 55
DMS BLM D-fir 45 20-75
Lindh Willamette NF D-fir 20 15-90 PCT
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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

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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

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Overstory Cover
Willamette National Forest Douglas-fir
Beggs 2005
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Overstory cover
McDonald Forest Douglas-fir, previously thinned
Newton and Cole 2004
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Crown structures
Suislaw National Forest Douglas-fir
Chan et al. 2005
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Foliage Height Diversity Index
35 m
30 m
25 m
20 m
15 m
10 m
5 m
0 m
lt
lt
STAND 1
STAND 3
STAND 2
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Foliage Height Diversity Index
3 to 5 years after thinning
Beggs 2005
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Impact of thinning on volume and on growth rate
(i.e., slope of volume curve)
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Acceleration of dominant old-growth
trees Diameter growth of largest 6 tpa
Growth (cm / yr)
Willamette National Forest
Beggs 2005
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Overstory Mortality ()
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)
Mostly competition related
Beggs 2005
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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

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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

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Seedling survival 8 growing seasons after thinning
Adapted from Maas-Hebner et al. 2005 FEM
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Seedling survival after 8 growing seasons
Adapted from Maas-Hebner et al. 2005 FEM
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Seedling survival
McDonald Douglas-fir
Newton and Cole 2004
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Harvesting damage to regeneration
Western Red Cedar Douglas-fir Grand Fir Western Hemlock
Total Damaged 41 46 35 45
McDonald Forest
Newton and Cole 2004
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Impact of light availability on seedling growth
Maas-Hebner et al. 2005
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Impact of overstory density
Western Hemlock
Newton and Cole 2004
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Effects of weed control
Western hemlock
Blodgett
Newton and Cole 2004
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Variation in overstory cover when gaps in
interspersed in thinned stands
40
35
30
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Frequency
20
15
10
5
0
0
10
20
30
40
50
60
70
80
90
100
Overstory Cover ()
Beggs 2005
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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

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• 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

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Questions