Skip to main content

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