This document describes using the Forest Vegetation Simulator (FVS) to simulate aspen and birch dynamics in a woodland heath community in Italy to aid in ecosystem restoration efforts. Field data was collected from 45 plots to develop 4 stages of forest development. FVS was calibrated and used to simulate forest growth over 40 years under different disturbance regimes, including periodic prescribed fires aimed at maintaining low forest basal area to conserve heather. Results showed forest encroachment without management but periodic burning maintained lower densities and basal areas.

1. Simula'ng
aspen/birch
dynamics
in
a
woodland
heath
community
FVS
applied
to
ecosystem
restora'on
Giorgio
Vacchiano,
Davide
Ascoli
Università
di
Torino
(Italy),
Dept.
Agriculture,
Silviculture
and
Land
Management
The
fourth
Forest
Vegeta'on
Simulator
conference
Fort
Collins,
18th
April
2012

2. -­‐ 2635
ha
-­‐ 240
÷
480
m
asl
-­‐ 12.3°C,
1200
mm/yr
-­‐ Glacial
terrace
(400k
yrs
BP)
-­‐ Loamy/acid
soils
Managed
Nature
Reserve
“Vauda”

3. “Vauda”
=
wald
Forest
historically
replaced
by
heathland
(harves'ng,
grazing)
Reserve
established
1993
to
protect
Calluna
(heather)
From:
Pavari,
A.,
1927.
L azione
antropica
sulla
vegetazione
forestale
in
rapporto
alla
fitogeografia.
L’Universo.
Italian
Military
Geographic
Ins'tute
(8)
873–896.

4. Altered
fire
regime
-­‐ Behaviour:
30
m/min
-­‐
8000
kW/m;
-­‐ Season:
February
-­‐
March
-­‐
Frequency:
1
–
5
yrs;
-­‐
Average
surface:
44
ha;
Source:
Ente
di
Ges'one
dei
Parchi
e
delle
Riserve
del
Canavese,
Regione
Piemonte
wildfire > 10 ha (1990-2012)

5. Quercus
robur
Robinia
sp.
Populus
tremula
Betula
pendula
Molinia
arundinacea
(tall
moor
grass)
Calluna
vulgaris
Fire
cycle
1-­‐2yrs
Fire
cycle
3+
yrs
&
grazing
reduced
Succession

6. Forest
encroachment
1976-­‐2004

7. Goal:
Conserva'on
of
Calluna
FVS
scenarios
-­‐>
variable
disturbance
regimes
Target
variable
=
forest
basal
area
<40
62
ac-­‐1

8. 45
plots
(BAF
=
4.356)
Sampling
and
input
data
(2012)
All
trees:
species,
dbh
3n
*
2
spp
*
3
size
classes:
height,
crown
size,
core
20
open-­‐grown
trees

9. Stage
1
(11
plots)
TPA
4500
-­‐
QMD
0.7’’
Age
5
-­‐
DomHt
9
n
Stage
2
(11
plots)
TPA
2500
–
QMD
2.1’’
Age15
-­‐
DomHt
40
n
Stage
3
(12
plots)
TPA
800
-­‐
QMD
4.0’’
Age
25
–
DomHt
49
n
Stage
4
(10
plots)
TPA
500
-­‐
QMD
6.0’’
Age
35
–
DomHt
60
n

10. Simula'on
parameters
(FVS-­‐NE)
Species
pairing
§ Populus
tremula
-­‐>
Quaking
aspen
§ Betula
pendula
-­‐>
Grey
birch
Plots
as
stands
Site
Index
aspen
=
67
(fiped
on
Carmean
1989)
TimeInt=
5
years
Simula'on
length:
40
years
(star'ng
2012)
No
seed
regenera'on
Natural
ini'al
regenera'on

11. Calibra'on
by
keywords
CWEqn
CrnMult
CalbStat
on
5yr
increment
+
ReadCorD
using
CalbStat
gross
average
(S2-­‐S4
plots)
SDImax
aspen
=
320
(was
280)

12. y
=
1520.6x-­‐0.623
y
=
47.477x-­‐0.158
1
10
100
100
1000
10000
QMD
(inches
x
2.54)
TPA
(x
2.47)
MortMSB
Observed
Linear
SDImax
Mature
Stand
Boundary
Star'ng
dbh
5.6
in
Slope
-­‐6.333

13. Results
–
no
management
0
2
4
6
8
10
12
14
16
2010
2020
2030
2040
2050
QMD
(in)
0
5000
10000
15000
20000
2010
2020
2030
2040
2050
TPA
0
10
20
30
40
50
60
70
2010
2020
2030
2040
2050
DOM
HT
(6)
0
20
40
60
80
100
120
140
2010
2020
2030
2040
2050
BA
(62
ac-­‐1)
S2
S3
S4

14. Rate Of
Spread
Intensity
Flame
Length
Mdf Depth Wtot
Unit m/min Btu/ft/s ft % ft Lb/ft2
Mean 4-6 3-450 5-7 12 1.4 0.209
Season:
early
winter
(December
–
January)
Frequency:
~15
yrs
à
heather
regenera'on
cycle
Rx:
Temp.
41-­‐47°F;
Rel.
Hum.
40-­‐60%;
Wind:
2-­‐5
mph
IgniYon
technique:
strip
head
fire
(accelera'on
15-­‐20
m)
Prescribed
fire
experiments

15. FFE
keywords
Simfire
every
15
years
(star'ng
2016)
§ 20’
windspeed:
15
mph
(midflame:
4
mph)
§ Moisture
class
3
§ Temperature
41°F
§ Burn
before
greenup
Custom
FuelModl
Moisture
(1hr
à
10%,
live
woody
à
65%)
-­‐>
fire
behavior
-­‐>
fire
effect
(mortality
and
sprou'ng)

16. Custom
fuel
model
Fuel loading (lb/ft2)
Live woody Dead woody Fuel load 1h/10h/100h Live herbaceous TOTAL
0.1430 0.022 0.044 / 0 / 0 0 0.209
Fuel layer structure
Height woody (ft) Height 1 h (ft) Cover % Live woody Cover % 1 h
0.7 (Calluna) 1.5 (Molinia) 41 59
Physical descriptors of the fuel model
S/V (ft2 ft-3)
Live woody
S/V (ft2 ft-3)
1h fuel
Heat (kj kg-1)
Live / 1h
Moisture
extiction
2575 2092 21414/18622 35%

17. Simulated
flame
length
5
n
Flame length (ft)
Year Mean 95% confidence int.
2016 5.50
4.62 6.38
2031 2.51
2.35 2.66
2046 2.58
2.31 2.85
6
n

18. DBH
(in)
Survival
probability
FFE
mortality
Field
experiments
Mortality
curve
-­‐
birch

19. Bark
thickness
(stump
height)
y
=
0.0447x
R²
=
0.77026
y
=
0.1098x
R²
=
0.66189
0.0
0.3
0.6
0.9
1.2
1.5
1.8
2.1
0.0
5.0
10.0
15.0
Bark
Thickness
(in)
Stem
diameter
(in)
4.5'
ht
0.3'
ht

20. DBH
(in)
Survival
probability
FFE
mortality
Field
experiments
FFE
refiped
Mortality
curve
-­‐
birch

21. Mortality
curve
-­‐
aspen
DBH
(in)
Survival
probability
FFE
mortality
Field
experiments
FFE
refiped

22. Aspen
sprout
mul'plier
(refiped
from
Crouch
1981)
y
=
39.863e-­‐0.059x
R²
=
0.92085
0
10
20
30
40
50
0
10
20
30
40
50
60
70
80
90
MulYplier
Aspen
BA
killed
(62
ac-­‐1)
Nsprouts
=
(40100.45
-­‐
3574.02*agesprout
2
+
554.02*agesprout
3
+
-­‐3.5208*agesprout
5
+
0.011797*agesprout
7)
*
(killed
BA/198)
*
mult

23. Results
–
prescribed
fire
0
2
4
6
8
10
12
14
16
2010
2020
2030
2040
2050
QMD
(in)
0
5000
10000
15000
20000
2010
2020
2030
2040
2050
TPA
0
10
20
30
40
50
60
70
2010
2020
2030
2040
2050
DOM
HT
(6)
0
20
40
60
80
100
120
140
2010
2020
2030
2040
2050
BA
(62
ac-­‐1)

24. Grazing
keywords
TimeInt
=
1
year
(aner
first
fire)
FixMort
(addi'onal
mortality)
§ Aspen
50%,
dbh
<0.3’’
§ Birch
50%,
dbh
<0.18’’
HtgStop
§ Ht
<
5
n
(goat
browsing)
§ Probability
of
damage
=
60%
§ H
growth
reduc'on
=
f(median
ht)

25. HtgStop
mul'plier
(from
field
experiments)
y
=
0.4542ln(x)
+
0.0916
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.0
1.0
2.0
3.0
4.0
5.0
6.0
HtgStop
mulYplier
Median
height
(6)

26. Results
–
prescribed
fire
and
grazing
0
2
4
6
8
10
12
14
16
2010
2020
2030
2040
2050
QMD
(in)
0
5000
10000
15000
20000
2010
2020
2030
2040
2050
TPA
0
10
20
30
40
50
60
70
2010
2020
2030
2040
2050
DOM
HT
(6)
0
20
40
60
80
100
120
140
2010
2020
2030
2040
2050
BA
(62
ac-­‐1)

27. No
managenent
15yr-­‐rota'on
prescribed
fire
15yr
rota'on
fire
+
yearly
grazing
Stand
structure
Stand
35,
year
40

28. Conclusions
• First
use
of
FVS
in
Italy
• Calibra'on
to
con'nue,
edit
code
• MSB
very
influen'al
(ar'fact
of
fire
damage?)
• Keywords
for
grazing,
1yr
cycles?
• Manager-­‐friendly?

29. S1 S2
S4 S3

30. …fire
up
your
ques'ons!