# Other Land Module (35_other)¶

## Description¶

The other land module describes the constraints under which natural vegetation (not classified as forest) and set-aside-land exists. The other land pool can be considered as a residual, consisting amongst others of snow, ice, scrubland and land no longer needed in the agricultural or livestock sector (set-aside land). At the same time the module calculates the corresponding carbon content of the area in the other land pool.

## Interfaces¶

### Input¶

Name Description Unit A B
$pcm\_land(j,"other",si)$ natveg land of the previous time step mio. ha x x
$fm\_carbon\_density(t,j,"other",c\_pools)$ carbon density in vegetation, soil and litter of current time step tC per ha x x
$sm\_years$ length of current time step years x
$vm\_land(j,"other",si)$ si class-specific other area in each cell mio. ha x x
$vm\_carbon\_stock(j,"other",c\_pools)$ cell and carbon pool specific carbon stock of other natural vegetation mio. tC x 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

## Realizations¶

### (A) static¶

In the static realisation the other land pool is hold fixed on the observed 1995 level:
\begin{equation}
vm\_land.fx(j,"other",si) = pcm\_land(j,"other",si);
\end{equation}

Correspondingly, also its carbon stock is fixed:
\begin{equation}
vm\_carbon\_stock.fx(j,"other",c\_pools) = \sum_{si} pcm\_land(j,"other",si) \cdot fm\_carbon\_density(t,j,"other",c\_pools));
\end{equation}

Limitations
Other land is fixed in size

### (B) endo_mar13 (default)¶

In the endo_mar13 realisation the other land pool can increase as well as decrease.

other land is calculated according to equation 1:

\begin{equation}
vm\_land(j,\text{"other"},si) = \sum_{land35} v35\_land(j,land35,si)
\end{equation}

other carbon stocks are calculated according to equation 2:

\begin{equation}
vm\_carbon\_stock(j,\text{"other"},c\_pools = \sum_{land35} \sum_{si} ( v35\_land(j,land35,si)) \cdot pc35\_carbon\_density(j,land35,c\_pools))
\end{equation}

The calculation of $pc35\_carbon\_density\_ac(j,ac,c\_pools)$ is based on exactly the same method as in 32_forestry and is also described in Humpenöder et al1 (2014)

Limitations
There are currently no known limitations of this realization.

### (C) endo_threshold_aug15¶

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

## Definitions¶

Name Description Unit A B
$v35\_land(j,land35,si)$ other land pools mio. ha x
$land35$ other land pools (new, grow, old) x
$pc35\_carbon\_density(j,land35,c\_pools)$ Area-weighted mean of pc35_carbon_density_ac(j,ac,c_pools) tC per ha x

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

## Developer(s)¶

Florian Humpenöder