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 |  |