Vegetation

The optional vegetation argument is a listdictionary of properties for vegetation and the soil. There must be one or more vegetation pools and there must be one or more soil pools. The values that can be set within the vegetation listdictionary are:

• Cvegpi: A vectorlist of preindustrial carbon stocks, in GtC, for each of the vegetation pools. Default is c(100,475,40)[100,475,40].
• tauveg: A vectorlist, of the same length as Cvegpi, of timescales, in yr, for the flows of carbon out of the vegetation pools (to the first soil pool). The default is c(100,25,1)[100,25,1]. Combined with the default Cvegpi, this gives a preindustrial NPP of 100/100 + 475/25 + 40/1 = 60 GtC/yr.
• NPPmax: The maximum NPP, in GtC/yr, when the atmospheric CO₂ concentration is no longer a limiting factor. This value must be greater than the sum of Cvegpi. Default is 80.
• albedo_forcing: The shortwave radiative forcing per deviation in the total amount of vegetative carbon (not including soil carbon) from the preindustrial value, in units of W/m²/GtC. Default is 0.002.
• tausoil: A vectorlist, of length equal to the number of desired soil pools, of timescales, in yr, for the flows of carbon out of the soil pools (a fraction soiloxi of which goes to the atmosphere and 1-soiloxi of which goes to the next soil pool). Default is c(10,1000)[10,1000].
• soiloxi: A vectorlist, of the same length as tausoil, of fractions of the flows of carbon out of the soil pools that are oxidized and sent to the atmosphere. The last element of this vectorlist must equal 1. Default is c(59/60,1)[59/60,1]. With a preindustrial NPP of 60 GtC/yr (see the note on tauveg above) and the default tausoil values (given above), this gives preindustrial soil carbon stocks of 60 x 10 = 600 GtC in the fast (10-yr) pool and 60 x (1-59/60) x 1000 = 1000 GtC in the slow (1000-yr) pool.
• soilQ10: The Q10 value for the soil decay rate, i.e., the factor by which the timescale of soil decay decreases for a 10-K temperature in surface temperature. Default is 1.5.