Forest land module (33_forest)


The forest land module describes the constraints under which forest areas exist. At the same time it calculates the corresponding carbon stocks of the forest areas. Within the forest land pool, intact and frontier forest (ifft) and modified natural forest (modnat) are distinguished.



Name Description Unit A B
$fm\_carbon\_density(t,j,land,c\_pools)$ carbon density in vegetation, soil and litter of current time step tC per ha x x
$vm\_land(j,land,si)$ areas of the different land types mio. ha x x
$pcm\_land(j,land,si)$ current area of different land types mio. ha x x
$vm\_carbon\_stock(j,land,c\_pools)$ The cell and carbon pool specific carbon stock of the forest land pool Mio tC x x
$pm\_land\_start(j,land)$ Initial land area mio. ha - x

The last columns of the table indicate the usage in the different realizations (numbered with capital letters)



Interface plot

Figure 0: Information exchange among modules


(A) static

In this implementation forest area is hold fixed on the observed 1995 level. Correspondingly, also its carbon stock is fixed.

Forest area:
vm\_land.fx(j,\text{"forest"},si) = pcm\_land(j,\text{"forest"},si)

Forest carbon stock:
vm\_carbon\_stock.fx(j,\text{"forest"},c\_pools) = fm\_carbon\_density(t,j,\text{"forest"},c\_pools) \sum_{si} pcm\_land(j,\text{"forest"},si)

fm_save_fore_protect is not taken into account. Fixing forest area corresponds to a full forest protection scenario.

(B) endo_mar13 (default)

In the endo_mar13 realisation forest area can shrink in size but not increase, i.e. ifft and modnat can be deforested and used for other purposes but regrowth of forest in the forest pool itself is not possible (regrowth of natural vegetation takes place in other land (35_other).

Forest area:
vm\_land(j,\text{"forest"},si) = \sum_{land33} v33\_land(j,land33,si)

Forest carbon stock:
vm\_carbon\_stock(j,\text{"forest"},c\_pools) = fm\_carbon\_density(t,j,\text{"forest"},c\_pools) \sum_{si} vm\_land(j,\text{"forest"},si)

The endo_mar13 realisation accounts for currently established forest protection schemes based on FRA20101 and comprises assumptions about the future development of forest protection schemes based on SRES and SSP scenarios. In addition forest areas designated for wood production, also based on FRA20101, are hold fixed.

The FRA20101 numbers relate to the total forest area in 2010. The total forest area in MAgPIE is the sum of the two land pools forest (33_forest) and forestry (32_forestry).
At first, the initial forestry area in MAgPIE (32_forestry) is counted towards the FAO2010 wood production areas. In case the initial MAgPIE forestry area is not sufficent to meet the reported FRA20101 wood production area on the regional level, the remaining wood production area is assigned to the MAgPIE forest land pool modnat. Forest protection areas are added on top of the forest areas excluded for wood production, with a preference of protecting ifft against modnat (3:1).

Figure 1: Forest protection scenarios in MAgPIE based on FRA2010.
Low: Forest protection is kept constant at 2010 level.
Medium: Forest protection doubles by 2100
High: Forest protection quadruples by 2100

Material from FRA2010

Forest is static in the first timestep
Forest can only decrease

(C) endo_threshold_aug15

endo_threshold_aug15 is based on the endo_mar13 realization. In addition, there is the option to shift forest land into the other land pools if the carbon density of forest in a simulation unit drops below a threshold of 20 tC/ha.


Name Description Unit A B
$v33\_land(j,land33,si)$ Forest land mio. ha - x
$land33$ Forest land pools (ifft, modnat) - - x


Florian Humpenöder

See Also

core, 39_landconversion, 57_maccs, 52_carbon, Overview, 35_other


1 FRA2010: Global Forest Resources Assessment 2010, Food and Agriculture Organization of the United Nations, 2010.

2 Bondeau, A., Smith, P.C., Zaehle, S., Schaphoff, S., Lucht, W., Cramer, W., Gerten, D., Lotze-Campen, H., Müller, C., Reichstein, M., Smith, B., 2007. Modelling the role of agriculture for the 20th century global terrestrial carbon balance. Glob Change Biol 13, 679–706.