applying density management to develop late successional features klaus j. puettmann oregon state...
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Applying Density Management to Develop
Late Successional Features
Klaus J. PuettmannOregon State
University
Studies
Study Location
Overstory Species
Age at thinnin
g% max
SDI Remarks
ODFOR Coast Range D-fir 5-20 NA
Standard plantations
NewtonCole Corvallis D-fir 50 20 – 40
Thinned previously
Blodgett W.
Hemlock 50 20 – 35
YSTDSWillamette NF D-fir 40 20 – 60
Wildcat Suislaw NF D-fir 30 10 – 55
DMS BLM D-fir 45 20-75
LindhWillamette NF D-fir 20 15-90 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
0
10
20
30
40
50
60
70
80
90
100
1997 1999 2001
Year
Co
ve
r (%
)
Control
Heavy
Light
LtGaps
Willamette National Forest: Douglas-fir Beggs 2005
0
10
20
30
40
50
60
70
0 2 4 6 8
Year
Perc
en
t Conifer Ultra-High
Conifer High
Conifer Medium
Conifer Low
Overstory cover
Newton and Cole 2004
McDonald Forest: Douglas-fir, previously thinned
Crown structures
20
40
60
0 8Year since thinning
LC
R %
Control
Light th.
Moderate th
Heavy th.
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 1 STAND 3STAND 2
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
CR MC CF SC
BLOCK
FH
D
Control
Heavy
Light
LtGaps
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
0
0.2
0.4
0.6
0.8
1
1.2
1.4
CR MC CF SC
Treatment
Control
Heavy
Light
LtGaps
Gro
wth
(cm
/
yr)
Willamette National ForestBeggs 2005
Douglas-fir
Golden chinquapin Hardwood
s
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 relatedBeggs 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
0
20
40
60
80
100W
. H
emlo
ck
S.
Spr
uce
D-fi
r
G.
fir
Redc
edar
Ald
er
B.
map
le
Survival
Adapted from Maas-Hebner et al. 2005 FEM
Seedling survival after 8 growing seasons
0
20
40
60
80
100W
. H
emlo
ck
S.
Spr
uce
D-fi
r
G.
fir
Redc
edar
Ald
er
B.
map
le
Survival
Good condition
Adapted from Maas-Hebner et al. 2005 FEM
0102030405060708090
100
Grand fir Cedar Hemlock Douglas-fir
Per
cent
Ultra-High
High
Medium
Low
Seedling survival
Newton and Cole 2004McDonald: Douglas-fir
Western Red Cedar
Douglas-fir Grand Fir Western Hemlock
Total % Damaged
41 46 35 45
Harvesting damage to regeneration
McDonald Forest Newton and Cole 2004
Impact of light availability on seedling growth
Maas-Hebner et al. 2005
0
20
40
60
80
100
120
140
160
0 2 4 6
Year
Cen
tim
ete
rs
High
Medium
Low
Western Hemlock
Newton and Cole 2004
Impact of overstory density
0
2
4
6
8
10
12
14
16
18
20
0 1 2 3 4 5 6
Year
Mill
imet
ers
High-Plant
Low-Plant
High-Spray
Low-Spray
Effects of weed control
Western hemlock
Newton and Cole 2004Blodgett
Variation in overstory cover when gaps in interspersed
in thinned stands
Frequency
0 10 20 30 40 50 60 70 80 90 100
Overstory Cover (%)
0
5
10
15
20
25
30
35
40
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