|Summary||On forest carbon cycle||
How to run
|General description||Examples for model output||
ACCOUNTING FUNCTION, VARIABLES AND PARAMETERS APPLIED IN CASMOFOR
Equations of CASMOFOR describing the carbon cycle are listed below by pool, and classified in various categories. Balance equations (BE) are ones that are used to calculate new values of the carbon pools at time t. FLUX IN refers to a process, i.e. a sink, by the yield of which the carbon content of the whole forestry system increases. Similarly, FLUX OUT refers to emissions by the amount of which the carbon content of the whole forestry system decreases. The emissions can come from carbon that was fixed by the FLUX IN processes, or from carbon that was already stored in the soil before the start of the simulation. Some carbon that flows through various pools eventually goes to the long-term SINK (in the soil), and remains part of the forestry system for the entire period of the simulation. Equations that are not classified into any of the above categories are used to calculate variables in the above equations, and are noted by other. By the forestry system all the pools and processes within the system boundary of the systems diagram are meant. Variables related to carbon pools and rates of fluxes are expressed as amount of carbon (tonnes of carbon tC), and is calculated once for each calendar year of the simulation for each species and yield class.
Each equation is shown twice in each cell: once with the long names of
the variables (in the first row(s) of each cell), and once using their symbols,
Index t refers to any year in the simulation, index (t-1) refers to the previous year.
Index (t-x) refers to year x year before the current year.
Index (i) means that the variable is a vector of values from year 1 to
year x (the factor used in the formula varies with age), where x depends on the
process. The respective values of some variables are found in the database of the model,
or should be specified by the user. The values of other variables are calculated
by the model itself.
To check that all carbon is accounted for, i.e. all incoming fluxes equal
to all outgoing fluxes + the changes of the carbon content of the system
(including permanent sinks), the below equation is tested after each simulation step
to ensure that mass is conserved:
Total Flux INt = Total (POOLSt POOLSt-1) + Total Flux to SINKt Total Flux OUTt
where Total Flux INt is the amount of carbon that enters the system in year t; Total Flux to SINKt is the amount of carbon that moves to long-term carbon sink pools of soil in year t; POOLSt POOLSt-1 are the amount of carbon in all pools in time t and t-1, respectively; and Total Flux OUTt is the amount of carbon that leaves the system in year t.
(Flux IN: amount entering the system; Flux OUT: amount leaving the system to air; Flus to SINK: amount leaving the system to soil and other long-term sink.)
EQUATIONS APPLIED TO MODEL CARBON DYNAMICS IN CASMOFOR:
II. CARBON ECONOMICS
1. NET ANNUAL FORESTRY COSTSt (EUR or HUF) = TOTAL of ALL ANNUAL COSTSt - TOTAL OF ALL ANNUAL REVENUESt
where TOTAL of ALL ANNUAL COSTSt (EUR or HUF) is the sum of all costs, at current prices, of all forestry operation on all area of the afforestation project that are due in year t; and TOTAL of ALL ANNUAL REVENUESt (EUR or HUF) is the sum of all revenues, at current prices, of all forestry operation on all area of the afforestation project that are due in year t.
2. TOTAL NET FORESTRY COSTSt (EUR or HUF) = SUMi(NET ANNUAL FORESTRY COSTSi)
where TOTAL NET FORESTRY COSTSt is the total costs from the beginning of the afforestation project, i.e. year 1, summed up to year t; and i = 1 to t.
3. TOTAL CARBON IN FORESTRY SYSTEMt = AGWBt + Rt + LLt + DWt + DLt + DRt + WPt + FWt + St
where TOTAL CARBON IN FORESTRY SYSTEMt is to total amount of carbon accumulated in all pools of the afforestation project area up to year t in all carbon pools since year 1; all other symbols as in the table above.
4. TOTAL NET SPECIFIC COSTSt (in EUR/tCO2 or HUF/CO2) = TOTAL NET FORESTRY COSTSt / TOTAL CARBON IN FORESTRY SYSTEMt
where TOTAL NET SPECIFIC COSTSt is the total net forestry costs per a tonne of CO2 sequestered by the afforestation system by year t.
TOTAL NET SPECIFIC COSTSt are also calculated with only the sum of AGWBt + Rt in the denominator to estimate total net specific costs of sequestering carbon in the tree biomass.
This webpage was last modified by Zoltan Somogyi 29 June 2014.