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# ## Control of the Wood Processing Model The Wood Processing Model (WPM) estimates the carbon content in different timber products and such carbon reservoirs as landfill and atmosphere over the given number of years. As input values WPM uses the pre-estimated amount of harvested wood from the 4C simulation, assumed a forest management was accomplished. A spinup file can be used to initialize single product, landfill and atmosphere pools with realistic values. First, the harvested wood is sorted in different timber grades which then are rearranged into different timber product groups. Then the product group carbon flow is simulated over the number of simulation years. The product groups have different life spans. The life span functions determine the half-life period of timber and therefore the recycled timber amount yearly. The timber removed from the product groups is partly recycled and returns into the timber cycle labelled as timber of age 0. The carbon cycle ends on landfill areas, by burning and hence in the atmosphere. A fixed percentage rate from the landfill carbon volatilises to the atmosphere where it accumulates over the years. The implementation of WPM is mainly based on Eggers (2002) and is described in detail in the [WPM-document]. ### Getting Started To get started following is required: Set the flag_wpm to the desired value Make sure forest management took action A spinup file must exist in the input directory (can be a dummy file)*. Flag Options
flag name | value | description
--- | --- | ---
flag_wpm | 0 | no calculation of sea and wpm
| 1 | calculation of wpm with the German parameter set
| 2 | SEA calculation
| 3 | WPM and SEA calculation
| 21, 31 | WPM with other parameter sets
### The Output Two output files are generated. The output includes the different sorted timber grades and the carbon amount in different timber categories per year. Output Files
extension | description
--- | ---
"_wpm" | carbon content in different pools after calculating - use categories - burning - landfill - atmosphere
"_wpm_inter" | intermediate steps of WPM carbon content in different products as - timber grades - industrial lines - product lines
### The Implementation The implementation of the WPM (Wood Processing Model) consists of data modules WPM functions implemented interfaces in the 4C simulation initial, allocate and deallocate functions #### Data Module data_wpm This section describes variables stored in the data_wpm module used for the WPM. data_wpm Description
stored in | description
--- | ---
mansort, standsort, manrec | data from the 4C simulation mansort: harvested wood standsort: standing stock manrec: management information
product_lines | product lines information: values and sorting parameters
use_categories | use categories: parameters and values
landfill | amount of carbon in landfill per year
burning | amount of burned carbon per year
atmo_year, atmo_cum | amount of carbon in the atmosphere, yearly and accumulated
debug, spinup | processing flags
life_span | parameters for the life span function half-life period parameters
proc_par | sorting parameters for product lines and use categories
nr_years | simulation years number
nr_management_years | management years number
nr_pr_ln | product lines number
pl | intermediate results of sequential sorting of the product lines ("_wpm_inter" output)
sum_use_cat | sums of use categories values per year
sum_input | sums of input carbon per year
use_cat | final use categories values, used for the output
#### The Functions The implemented functions correspond to the single steps of the WPM and are proceeded sequently. The overview of the single processes can be seen in [WPM-document]. Subroutines Description
subroutines | content description
--- | ---
calculate_product_lines | sorting and aggregation of the removals into the product lines / roundwood for each management year
calculate_wood_processing | the already calculated product lines sortings due to the parameters industrial lines (IL) => product lines (PL) => use categories (UC)
calculate_use_categories | aggregation of the product lines to the initial use categories values for each management year
calculate_output | calculations of the carbon distribution in the pools as result of the timber circle and the recycling process
#### The Coupling to the 4C implementation The coupling of the WPM and the 4C implementation can be distinguished into two parts the input interface and the output interface As mentioned above, WPM uses both the mansort and the manrec data modules and some general information such as number of simulation years as input data. For the output the changes were made to match the 4C output interface in three files: amod_out.f, old_out.f, output.f. The deallocation of wpm is called after one simulation run is over in finisim.f Input Interface
data | where
--- | ---
mansort | sorting of timber in timsort.f
manrec | management subroutines in management.f
year etc. | import of the data_simul module
WPM Subroutine Calls in 4C
content | Fotran files
--- | ---
WPM subroutine calls | simul.f finisim.f
WPM data, subroutines etc. | wpm.f wpm_wood_proc.f amod_wpm.f
output interface | amod_out.f old_out.f output.f
input interface | timsort.f management.f simul.f amod_simul.f
#### The spinup file The initial values of all the product lines, use categories, landfill, burning and atmosphere pools are filled with 0. This is not a realistic approach because the wood production might have been running for decades before the beginning of the simulation. The spinup file contains estimated initial values for the mentioned pools. The spinup process is based on an ordinary WPM calculation. A mansort file with continually input of harvested wood is used as input. A proper simulation time was selected to make sure the pools volumes become steady over the years. The spinup file preparation is released as a separate tool. As mentioned above, it needs a hand-made mansort and manrec files. The output is a spinup file. _________________________________________________________________ * The spinup file for WPM can be set by the PC version of 4C which includes a GUI. #
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