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Table 2 3PG model parameters for the target species

From: A spatially explicit approach to modeling biological productivity and economic attractiveness of short-rotation woody crops in the eastern USA

3PG symbol

Description

Pinus taeda

Eucalyptus benthamii

Eucalyptus grandis

Hybrid poplar North

Populus deltoides South Upland

Populus deltoides South Lowland

Units

Allometric relationships and partitioning

 pFS2

Ratio of foliage:stem partitioning at stem diameter = 2 cm

0.4

0.6

0.6

0.6

0.5

0.5

 

 pFS20

Ratio of foliage:stem partitioning at stem diameter = 20 cm

0.25

0.25

0.25

0.4

0.3

0.3

 

 StemConst

Constant in stem mass v diameter relationship

0.1

0.15

0.15

0.095

0.095

0.095

 

 StemPower

Power in stem mass v diameter relationship

2.5

2.8

2.8

2.5

2.5

2.5

 

 PRx

Maximum fraction of NPP to roots

0.4

0.6

0.6

0.25

0.3

0.3

 

 PRn

Minimum fraction of NPP to roots

0.2

0.2

0.2

0.15

0.2

0.2

 

Temperature modifier

 Tmin

Minimum temperature for growth

4

4

8

5

5

5

°C

 Topt

Optimum temperature for growth

25

25

25

20

25

25

°C

 Tmax

Maximum temperature for growth

38

36

36

40

40

40

°C

Frost modifier

 kF

Number of days production lost for each frost day

1

3

5

1

1

1

Days

Age modifier

 MaxAge

Maximum stand age

35

50

50

50

50

50

Years

 nAge

Power of relative age in fage

3

9

9

2

15

15

 

 rAge

Relative age to give fage = 0.5

0.2

35

0.95

0.9

0.9

0.9

 

Litterfall and root turnover

 gammaFx

Maximum litterfall rate

0.042

0.07

0.07

0.25

0.25

0.25

month−1

 gammaF0

Litterfall rate at t = 0

0.001

0.15

0.15

0.001

0.001

0.001

month−1

 tgammaF

Age at which litterfall rate has median value

18

35

35

15

15

15

month

 Rttover

Average monthly root turnover rate

0.0168

0.009

0.009

0.005

0.002

0.002

month−1

Conductance

 MaxCond

Maximum canopy conductance

0.006

0.03

0.03

0.02

0.02

0.02

m s−1

 LAIgcx

Canopy LAI for maximum canopy conductance

3

3.33

3.33

3.33

3.33

3.33

–

 CoeffCond

Defines stomatal response to VPD

0.025

0.05

0.05

0.06

0.05

0.043

mbar−1

 BLcond

Canopy boundary layer conductance

0.1

0.2

0.2

0.2

0.2

0.2

m s−1

Fertility effects

 m0

Value of m when FR = 0

0.1

0

0

0

0

0

 

 fN0

Value of fN when FR = 0

0.5

0.6

0.6

1

1

1

 

Stem mortality

 wSx1000

Maximum stem mass per tree at 1000 trees/ha

235

300

300

100

220

220

kg tree−1

 thinPower

Power in self-thinning law

1.7

1.6066

1.6066

1.5

1.5

1.5

 

 mF

Fraction of mean foliage biomass per tree on dying trees

0

0

0

0

0

0

 

 mR

Fraction of mean root biomass per tree on dying trees

0.2

0

0

0

0

0

 

 ms

Fraction of mean stem biomass per tree on dying trees

0.4

0.2

0.2

0.2

0.2

0.2

 

Canopy structure and processes

 SLA0

Specific leaf area at stand age 0

6.4

9.1

7.5

12

12

12

m2 kg−1

 SLA1

Specific leaf area for mature aged stands

6

9.1

7.5

11

11

11

m2 kg−1

 tSLA

Age at which specific leaf area = ½(SLA0 + SLA1)

4

4

4

1.5

1.5

1.5

Years

 k

Extinction coefficient for absorption of PAR by canopy

0.57

0.5

0.5

0.5

0.5

0.5

–

 fullCanAge

Age at full canopy cover

2

1.25

1.25

1

3

3

Years

 MaxIntcptn

Maximum proportion of rainfall intercepted by canopy

0.2

0.15

0.15

0.15

0.15

0.15

–

 LAImaxIntcptn

LAI for maximum rainfall interception

5

3

3

3.3

3.3

3.3

–

 Alpha

Canopy quantum efficiency

0.0485

0.06

0.06

0.05

0.04965

0.062

mol C mol PAR−1

Branch and bark fraction

 fracBB0

Branch and bark fraction at stand age 0

0.4

0.3

0.3

0.2

0.2

0.2

 

 fracBB1

Branch and bark fraction for mature aged stands

0.1

0.12

0.12

0.1

0.1

0.1

 

 TBB

Age at which branch and bark fraction = ½ (fracBB0 + fracBB1)

15

2

2

1

1

1

 

Various

 Y

Ratio NPP/GPP

0.47

0.47

0.47

0.47

0.47

0.47

 

 Density

Basic density

0.5

0.55

0.5

0.35

0.35

0.35

tons m−3

 volRatio

Ratio Vob/Vib

1.25

1.25

1.25

1.25

1.25

1.25

Â