This module provides demand for forestry products via the interface
pm_demand_forestry to the modules 32_forestry and 62_material, and merges production of timber
from different sources into the interface vm_prod, which is
used in the 17_production and 21_trade modules.
| Description | Unit | A | |
|---|---|---|---|
| im_gdp_pc_ppp_iso (t_all, iso) |
Per capita income in purchasing power parity | \(USD_{05PPP}/cap/yr\) | x |
| im_pop_iso (t_all, iso) |
Population | \(10^6/yr\) | x |
| sm_fix_SSP2 | year until which all parameters are fixed to SSP2 values | \(year\) | x |
| vm_prod (j, k) |
Production in each cell | \(10^6 tDM/yr\) | x |
| vm_prod_forestry (j, kforestry) |
Production of woody biomass from commercial plantations | \(10^6 tDM/yr\) | x |
| vm_prod_natveg (j, land_natveg, kforestry) |
Production of woody biomass from natural vegetation | \(10^6 tDM/yr\) | x |
| Description | Unit | |
|---|---|---|
| im_timber_prod_cost (kforestry) |
Cost for producing one unit of wood and woodfuel | \(USD/tDM\) |
| pm_demand_forestry (t_ext, i, kforestry) |
Extended demand for timber beyound simulation | \(10^6 tDM/yr\) |
| vm_cost_timber (i) |
Actual cost of harvesting timber from forests | \(10^6 USD/yr\) |
In this realization, aggregated timber demand for wood and woodfuel
pm_demand_forestry is calculated based on demand equation
from Lauri et
al. (2019) and income elasticities from Morland et al. (2018). See
Mishra et al.
(2021) for more details. This realization
can also account for construction wood demand based on Churkina et al. (2020)
which is added on top of industrial roundwood demand (see Mishra et al. (2022)). Timber can be produced from both
timber plantations vm_prod_forestry provided by 32_forestry and natural vegetation
vm_prod_natveg provided by 35_natveg.
Timber production cost include the cost for producing wood, woodfuel and residues, and technical costs for a slack variable (‘v73_prod_heaven_timber’). The slack variable (high costs) is only used as a last resort when there is no other way to meet the timber demand. The purpose of the slack variable is to assure technically feasibility of the model under all conditions and to indicate shortage of wood supply, if any.
\[\begin{multline*} vm\_cost\_timber(i2) = \sum_{cell(i2,j2),kforestry}\left( vm\_prod(j2,kforestry) \cdot im\_timber\_prod\_cost(kforestry)\right) + \sum_{cell(i2,j2)} v73\_prod\_residues(j2) \cdot s73\_reisdue\_removal\_cost + \sum_{cell(i2,j2),kforestry}\left( v73\_prod\_heaven\_timber(j2,kforestry) \cdot s73\_free\_prod\_cost\right) \end{multline*}\]
The following equations describes cellular level production (in dry
matter) of woody biomass vm_prod as the sum of the cluster
level production of timber coming from ‘vm_prod_forestry’ and
‘vm_prod_natveg’. When production capabilities are exhausted, the model
can produce roundwood without using any land resources but by paying a
very high cost (‘s73_free_prod_cost’). Timber production equation is
split in two parts, one each for industrial roundwood and wood fuel
production. Woodfuel production, in addition to usual production
channels, can also use residues left from industrial roundwood harvest
for meeting overall wood fuel production targets.
\[\begin{multline*} vm\_prod(j2,"wood") = vm\_prod\_forestry(j2,"wood") + \sum_{land\_natveg}vm\_prod\_natveg(j2,land\_natveg,"wood") + v73\_prod\_heaven\_timber(j2,"wood") \end{multline*}\]
\[\begin{multline*} vm\_prod(j2,"woodfuel") = vm\_prod\_forestry(j2,"woodfuel") + \sum_{land\_natveg}vm\_prod\_natveg(j2,land\_natveg,"woodfuel") + v73\_prod\_residues(j2) + v73\_prod\_heaven\_timber(j2,"woodfuel") \end{multline*}\]
Production of residues is calculated based on
s73_residue_ratio. This fraction of industrial roundwood
production is assumed to be lost during harvesting processes. USDA
reports that ca. 30% of roundwood harvested are residues (Oswalt et al. (2019)). Not
all of this residue is recovered from forest and we assume 50% of
residue removal based on Pokharel et al. (2017).
These numbers (residue levels and residude removals vary strongly among
different studies, the numbers used here are from a USDA report on state
of forests in USA which has consistent reporting over years)
\[\begin{multline*} v73\_prod\_residues(j2) \leq vm\_prod(j2,"wood") \cdot s73\_residue\_ratio \end{multline*}\]
Limitations Timber demand cannot be determined endogenously
| Description | Unit | A | |
|---|---|---|---|
| f73_construction_wood_demand (t_all, i, pop_gdp_scen09, build_scen) |
Construction wood demand | \(10^6 tDM\) | x |
| f73_demand_modifier (t_ext, scen_73) |
Factor diminishing paper use | \(1\) | x |
| f73_income_elasticity (total_wood_products) |
Income elasticities of wood products | \(1\) | x |
| f73_prod_specific_timber (t_all, iso, total_wood_products) |
End use timber product demand | \(10^6 m3/yr\) | x |
| f73_regional_timber_demand (t_all, i, total_wood_products) |
End use timber product demand | \(10^6 m3/yr\) | x |
| f73_volumetric_conversion (kforestry) |
Volumetric conversion from mio t to m3 of wood | \(1\) | x |
| p73_demand_calib (t_all, i, kforestry) |
Additive calibration for timber demand | \(10^6 m3/yr\) | x |
| p73_demand_constr_wood (t_all, i) |
Demand for construction wood | \(10^6 tDM/yr\) | x |
| p73_demand_modifier (t_all) |
Simple demand modifier for construction wood | \(10^6 tDM/yr\) | x |
| p73_forestry_demand_prod_specific (t_all, iso, total_wood_products) |
End product specific timber demand | \(10^6 m3/yr\) | x |
| p73_fraction (t_all) |
Fraction over which construction wood demand is spread out | \(1\) | x |
| p73_fraction_sm_fix | Modifier fraction at sm_fix_SSP2 time step | \(1\) | x |
| p73_glo_wood (t_all, kforestry) |
Global wood demand | \(10^6 tDM/yr\) | x |
| p73_timber_demand_gdp_pop (t_all, i, kforestry) |
Timber demand based on lauri et al 2019 | \(10^6 m3/yr\) | x |
| q73_cost_timber (i) |
Actual cost of harvesting timber from forests | \(10^6 USD/yr\) | x |
| q73_prod_residues (j) |
Production of residues from industrial roundwood harvest | \(10^6 tDM/yr\) | x |
| q73_prod_wood (j) |
Production of industrial roundwood | \(10^6 tDM/yr\) | x |
| q73_prod_woodfuel (j) |
Production of wood fuel | \(10^6 tDM/yr\) | x |
| s73_expansion | Construction wood demand expansion factor by end of century based on industrial roundwood demand as base | \(1=100 percent increase\) | x |
| s73_free_prod_cost | Very high cost for settling demand without production | \(USD/tDM\) | x |
| s73_increase_ceiling | Limiter for not allowing a demand jump between time steps beyond a certain limit | \(1\) | x |
| s73_reisdue_removal_cost | Cost of removing residues left after industrial roundwood harvest | \(USD/tDM\) | x |
| s73_residue_ratio | Proportion of overall industrial roundwood production which ends up as residue during harvest | \(1\) | x |
| s73_timber_demand_switch | Logical switch to turn on or off timber demand 1=on 0=off | \(1\) | x |
| s73_timber_prod_cost_wood | Cost for producing one unit of wood | \(USD/tDM\) | x |
| s73_timber_prod_cost_woodfuel | Cost for prodcing one unit of woodfuel | \(USD/tDM\) | x |
| v73_prod_heaven_timber (j, kforestry) |
Production of woody biomass from heaven | \(10^6 tDM/yr\) | x |
| v73_prod_residues (j) |
Production of residues from industrial roundwood harvest | \(10^6 tDM/yr\) | x |
| description | |
|---|---|
| build_scen | Building wood scenario |
| cell(i, j) | number of LPJ cells per region i |
| construction_wood(total_wood_products) | Wood products used for building construction |
| i | all economic regions |
| i_to_iso(i, iso) | mapping regions to iso countries |
| i2(i) | World regions (dynamic set) |
| iso | list of iso countries |
| j | number of LPJ cells |
| j2(j) | Spatial Clusters (dynamic set) |
| k(kall) | Primary products |
| kforestry_to_woodprod(kforestry, total_wood_products) | Mapping between intermediate and end use wood products |
| kforestry(k) | forestry products |
| land_natveg(land_timber) | Natural vegetation land pools |
| pop_gdp_scen09 | Population and GDP scenario |
| scen_73 | Forestry future scenario |
| t_all(t_ext) | 5-year time periods |
| t_ext | 5-year time periods |
| t_past_forestry(t_all) | Forestry Timesteps with observed data |
| t(t_all) | Simulated time periods |
| total_wood_products | End use wood product category from FAO |
| type | GAMS variable attribute used for the output |
| wood_panels(wood_products) | Wood products used for panels construction |
| wood_products(total_wood_products) | Major 2nd level products from wood processing |
Abhijeet Mishra, Florian Humpenöder
09_drivers, 11_costs, 17_production, 32_forestry, 35_natveg, 62_material