Transcript Primerjava naravne in umetne obnove gozdov prizadetih v

Does salvage logging influence
forest recovery following partial
canopy disturbances in beech
dominated forests?
Gal FIDEJ, Andrej ROZMAN, Tihomir RUGANI,
Tom NAGEL, Igor DAKSKOBLER, Jurij DIACI
Introduction
• Abundant literature about
negative ecological effects
on salvage logging.
• Beech dominated forests
and small to medium scale
disturbance frequent in
Slovenia. Question: how to
react in these situations?
• Goal: analyze the influence
of salvage logging in these
situations.
Methods
• Retrospective study.
• Influence of salvage logging
was analyzed on 8 sites
throughout Slovenia.
• Beech dominated forests.
• Every site 2 stratum: salvaged
and NON-salvaged part ->
stratified random
subsampling for plots.
Methods
Methods
• Regeneration above 20 cm in 4 height classes:
1.
2.
3.
4.
20-50 cm
51-130 cm
131 cm - 5 cm DBH
>5 cm DBH
• Phytosociological mapping (Braun-Blanquet, 1964) of
plants.
• Analysis: treatment effect (salvage – no salvage) on
regeneration (composition, density, height structure)
were analysed with linear mixed-effects models
(LMMs) in R. Other ecological factors were also
included in the model.
Study sites
Site
Bohor
Črmošnjice
Kosmate
doline
Bedrock
dolomite-limest. +
silicates intrusion
2008
1983,
2006
wind 300-460
S
5,5
mature f.
yes
tractor
mature f.
yes
cable cr.
mature f.
no
tractor
1993
Lesično
limestone
dolomite-limest. +
silicates intrusion
700-830 NE 1,3
1250wind 1300 NW-N 0,7
2008
wind 400-500 NW
2,0
mature f.
no
cable cr.
Nemškarca
dolomite
2006
wind 610-750 N-NE
1,5
no
cable cr.
Otuška
dolomite
2006
wind 270-380 E-NE
1,5
mature f.
pole s.,
mature f.
no
tractor
Zadlog
dolomite
dolomitelimestone
2006
wind 700-750
1,1
mature f.
yes
cable cr.
2006
wind 400-500 N-NE
0,6
mature f.
yes
cable cr.
Zala
dolomite
Year of
Size
Adv.
dist. Distur. Alt. (m) Exp. (ha) Dev. Stage Reg. Sal. Tech.
ice
N
SAL
NSAL
N
24
27
Mean
15441,7
12907,4
Median
11000,0
5800,0
40000
20000
0
• Density higher on SAL (Not
st. sig.).
• LMM = treatment,
altitude, slope, rockiness,
CWD.
• Density in neg.
relationship with altitude
(-0,41) and CWD (-0,29).
Density (ha-1)
Results – Regeneration density
nsal
Min
800,0
100,0
Max
43700,0
51100,0
sal
Std. Dev.
13127,0
13410,7
Coef. Var.
85,0
103,9
Results – Species diversity
5000
trees/ha
• Beech dominates on
all sites.
• Followed by more
light demanding
species.
6000
4000
3000
2000
NSAL
1000
SAL
Fagus s.
Acer pseud.
Fraxinus m.
Acer plat.
Carpinus b.
Tilia sp.
Ostrya c.
Ulmus g.
Picea a.
Fraxinus exc.
Acer camp.
others
0
All species n.
Shannon all sp.
Tree sp. number
Shannon tree sp.
N
64
64
64
64
Mean Median Min
44.3 44.0 22.0
2.5
2.6
1.2
6.2
6.0
2.0
1.0
1.0
0.0
Max Std.Dev. Coef.Var.
72.0
10.9
24.6
3.2
0.4
15.3
12.0
2.7
43.0
2.0
0.5
48.3
Results – Species diversity
nsal
sal
treat*nmv2
2.5
1.5
2.0
Shannon
3.0
2.5
2.0
nsal
sal
nsal.subm
treat
treat*nmv2
sal
treat
nsal.subm
treat*nmv2
13
11
12
nsal
sal
treat
2.0
1.0 1.5
3
0.0 0.5
1.0 1.5
Shannon.tree
3
0.0 0.5
4
2
nsal
Shannon.tree
10
8
43
6
tree.num
8
6
4
tree.num
10
2.0
Trees
2
• Shannon for trees
not statistically
different.
1.5
nsal.subm
treat
• Shannon index
decreased with
altitude.
Shannon
60
40
20
20
40
spc.num
60
14
3.0
Plants
spc.num
• Shannon index for
plant diversity
slightly higher in
NON-SAL (Not St.
sig.).
nsal.subm
treat*nmv2
Results – Height structure
trees/ha
• Higher density of smaller regeneration and lower density of
taller regeneration on salvaged areas, but not st. significant.
8000
7000
6000
5000
4000
3000
2000
1000
0
NSAL
SAL
21-50 cm 51-130 130-5 cm 5+ cm dbh
cm
dbh
Results – Height structure
6000
• Tree sp. ratio
similar in 1.
and 2. H class.
NON-SAL
5000
4000
3000
2000
• Third H class:
beech prevails
on SAL sites.
1000
0
6000
• 3. class:
advanced
regeneration
and salvaging?
trees/ha
5000
SAL
4000
3000
?
2000
Fraxinus m.
Acer platan.
Acer pseud.
Ostrya c.
1000
Fagus s.
0
21-50 cm 51-130 130-5 cm 5+ cm dbh
cm
dbh
Carpinus b.
Results – Height of dominant trees
• Small, but
statistically sig.
difference (LMM; p
= 0.0019) between
height of dominant
trees.
NSAL
SAL
N
Mean (cm) Median
213.0
142.5
120.0
254.0
118.4
91.5
Min
16.0
21.0
Max Std. Dev.
530.0
105.6
1360.0 115.7
Coef. Var.
74.1
97.7
Results – Plant Coverage
• Slightly more
coverage in tree and
shrub layer on NSAL
sites, but differences
not stat. significant.
nsal
sal
treat
100
E1
60
100
60
20
20
11
19
3
20
E2
10 20 30 40
13
10
14
Herb layer
Shrub layer
0
E3
Tree layer
nsal
sal
treat
5
6
11
12
1
nsal
sal
treat
Results – Plant coverage by logging technique
100
100
80
E1
60
17
15
16
0
20
20
10
7
40
40
36
60
E2
30
20
E3
16
17
15
80
39
ccrane
tr
ccrane
tech
tr
ccrane
tech
tr
tech
nsal
sal
treat
80
60
20
20
37
13
12
19
40
40
E1
60
E2
20
36
7
10
E3
30
80
39
100
100
40
Treatment
0
• Sig. Diferences
between logging
method in shrub
layer (p=0,009).
40
Logging technique
nsal
sal
treat
37
38
17
15
16
nsal
sal
treat
Results – Erosion
30
20
50
1
46
29
12
11
13
0
• 28 plots (55%) without
erosion.
35
10
• Low erosion; mean= 4.1 %
(0-30%)
eroz
Treatment
nsal
sal
15
29
35
12
11
10
13
46
5
14
0 5
• No. Sig. differences
between logging method
eroz
• No sig. differences between
treatments
25
treat
Logging
method
ccrane
tr
tech
Results – Browsing
• Slightly higer but significant
(Chi-2, p=0,000) browsing
damages on salvaged sites
100
80
60
NSAL
40
SAL
20
0
1
2
3
1: no or up to 10 % of lateral shoots
2: terminal and/or < 50 % lateral s.
3: terminal + majority of lateral s.
Discussion
• No major differences in term of density,
structure, species composition.
• Removing deadwood decreases biodiversity.
• Dead wood – potential substrate for
regeneration in future (spruce, fir).
• No differences in erosion – skidding trails were
excluded from plots.
• Logging method!
Sites
Site
Bohor
Črmošnjice
Kosmate doline
Lesično
Year of
Size
dist. Distur. Alt. (m) Exp. (ha) Dev. Stage
Bedrock
dolomite-limestone +
silicates
2008
1983,
dolomite
2006
limestone
1993
dolomite-limestone +
silicates
2008
wind 300-460
S
Adv.
Reg.
Sal.
Method
5,5
mature f.
yes
tractor
700-830 NE 1,3
1250wind 1300 NW-N 0,7
mature f.
yes
cable cr.
mature f.
no
tractor
wind 400-500 NW
1,1
mature f.
no
cable cr.
no
cable cr.
no
tractor
ice
Nemškarca
dolomite
2006
wind 610-750 N-NE 1,5
Otuška
dolomite
2006
wind 270-380 E-NE
1,5
mature f.
pole s.,
mature f.
Zadlog
dolomite
2006
wind 700-750
1,1
mature f.
yes
cable cr.
Zala
dolomite-limestone
2006
wind 400-500 N-NE 0,6
mature f.
yes
cable cr.
N
Conclusions
• Salvage logging is a viable option in cases of
relatively small (to intermediate) scale
disturbances on beech sites.
• Decision making on salvaging: consider the
size of affected area, relief, altitude,
inclination, bedrock type (erodibility),
advanced regeneration, soil type, presence of
forest roads, skidding trails,…and economics.
Thank you for your attention!