| | 196 | 70% of the global forest are managed invalidating the assumption in previous versions of ORCHIDEE that forests are long-lived natural vegetation. Forest management, inspired by ORCHIDEE-FM was implemented in ORCHIDEE-CAN. Owing to the allometric allocation scheme, the introduction of diameter classes and a canopy structure only the principles, i.e., Deleuze and Dhote and RDI based management were retained. If the forest management strategy is not specified the default value "unmanaged" (FM = 1) is used. This implies that there are no thinning or harvest. Once the stand density drops below the threshold or the tree diameter exceeds another threshold a stand replacing disturbance is applied and a new stand is prescribed in the next time step. Therefore, the biomass pools in ORCHIDEE-CN-CAN no longer depend on a prescribed longevity. |
| | 197 | |
| | 198 | When developing and testing the model, a single forest management strategy can be applied for all pixels and PFTs. ORCHIDEE-CN-CAN distinguishes 4 different strategies: |
| | 199 | |
| | 200 | 1 – FM=1 unmanaged |
| | 201 | |
| | 202 | 2 – FM=2 high stand management: with RDI based thinnings and density/diameter based final harvest |
| | 203 | |
| | 204 | 3 – FM=3 coppice |
| | 205 | |
| | 206 | 4 – FM=4 short rotation coppice with willow or poplar |
| | 207 | |
| | 208 | Set '''read_fm_map''' to n and specify the desired management strategy (1-4) through '''forest_managed_forced'''. |
| | 209 | |
| | 210 | For applications that focus on forestry or require landscape heterogeneity, a PFT-specific management strategy can be read from a spatially explicit map. Thus, the same PFT in different pixels can be assigned a different management strategy. However, within a pixel a single PFT can only have one management strategy. Unless, one wants to run forest management over Europe the user will have to create his/her forest management maps first. Set '''read_fm_map''' to y and specify the location of the forest management map in COMP/stomate.card. Check the existing forest management maps for Europe for an example of how the map should be defined. |
| | 211 | |
| | 212 | When prescribing a forest stand (independent of forest management) the Initial density '''nmaxtrees''', and the range of the initial tree height of the seedlings needs to be specified '''height_init_min''' and '''height_init_max'''. Irrespective of the management strategy the maximum carrying capacity needs to be described. Carrying capacity was formalized through the self-thinning relationship which makes use of two parameters '''alpha_self_thinning''' and '''beta_self_thinning'''. As a fail-safe option the longevity of a stand is still defined but should only be used when all other criteria fail to kill the stand (not observed). Longevity is defined by the parameter '''residence_time'''. |
| | 213 | |
| | 214 | The details of each of the 4 management strategies can be refined through a set of PFT-specific parameters. Note that not every management strategy makes use of all parameters. For more details see the SI of Naudts et al 2015 (last table). The different management strategies require parameter values for : first thinning height '''h_first''', stand replacing density '''ntrees_dia_profit''', harvest diameter '''max_harvest_dia''', ccppice diameter '''coppice_diameter''', rotation length '''src_rot_length''', number of rotations '''src_nrots''', fuelwood diameter '''fuelwood_diameter''' and the minimum and maximum alpha and beta (thus 4 parameters) specifying the RDI range '''alpha_rdi_upper''', '''alpha_rdi_lower''', '''beta_rdi_upper''' and '''beta_rdi_lower'''. |
| | 215 | |
| | 216 | According to economic theory, high-stand forest are harvested when the actual growth drops below the long-term growth. This has been implemented in ORCHIDEE-CAN and ORCHIDEE-CN-CAN. This feature was found to be very sensitive to the time frame for which actual increment was calculated. This option can be by-passed by setting this period unrealistically high, for example, '''n_pai''' =1000. Persons interested in further testing/developing this feature should set this parameter (unit: years) to 5 or 10. |
| | 217 | |
| | 218 | While developing the code some conflicts were encountered between RDI and self-thinning. As a first solution an additional threshold was introduced '''rdi_limit_upper'''. When debugging progressed this threshold was set to 0.99 (if set to 1.00 there is no correction any more). The initial problem was resolved but the initial fix has not been removed yet. For the time being set rdi_limit_upper to 0.99. |
| | 219 | |
| | 220 | CHECK: MAX_HARVEST_DIA |
| | 221 | |
| 198 | | The code distinguishes between three options to check for mass balance problems. These options are controlled by the parameter '''ERR_ACT'''. Always use ERR_ACT = 3 when developing and testing the code. Note that in addition to checking for mass balance closure ORCHIDEE-CN-CAN will also check for the preservation of veget_max. This is useful to make sure no surface area is lost when moving biomass from one PFT to another following natural disturbances, forest management, land cover changes and when using age classes. In some parts of the code, for example, modules that deal with disturbances, it is assumed that the tallest trees are stored in the last diameter class. When the difference in diameter between diameter classes becomes very small, this assumption could be violated. Therefore, the diameter classes are sorted to enforce the assumed order and where needed the order is checked. |
| 199 | | |
| 200 | | 1 - ERR_ACT = 1 is recommended when running global long-term simulations. Under this option, mass balance closure is checked for all biogeochemical processes but only at the highest level thus stomate.f90 and stomate_lpj.f90. Although the mass balance checks are not very expensive in terms of computer time, skipping the numerous lower level checks is expected to save some time. Under this option the mass balance error is only written to the history file. No information is provided in which subroutine the problem occurred. |
| 201 | | |
| 202 | | 2 - ERR_ACT = 2 is recommended when developing and testing the model. Now the mass balance is explicitly checked in stomate.f90, stomate_lpj.f90 and all its subroutines. Under this option the mass balance error is written to the history file and if the mass balance is not closed, the warning message will indicate in which subroutine the problem likely originated. |
| 203 | | |
| 204 | | 3 - ERR_ACT = 3 is recommended when having a problem with mass balance closure. The mass balance is explicitly checked in stomate.f90, stomate_lpj.f90 and all its subroutines. If a mass balance occurs, the model is stopped. |
| | 224 | The code distinguishes between three options to check for mass balance problems. These options are controlled by the parameter '''err_act'''. Always use err_act = 3 when developing and testing the code. Note that in addition to checking for mass balance closure ORCHIDEE-CN-CAN will also check for the preservation of veget_max. This is useful to make sure no surface area is lost when moving biomass from one PFT to another following natural disturbances, forest management, land cover changes and when using age classes. In some parts of the code, for example, modules that deal with disturbances, it is assumed that the tallest trees are stored in the last diameter class. When the difference in diameter between diameter classes becomes very small, this assumption could be violated. Therefore, the diameter classes are sorted to enforce the assumed order and where needed the order is checked. |
| | 225 | |
| | 226 | 1 - err_act = 1 is recommended when running global long-term simulations. Under this option, mass balance closure is checked for all biogeochemical processes but only at the highest level thus stomate.f90 and stomate_lpj.f90. Although the mass balance checks are not very expensive in terms of computer time, skipping the numerous lower level checks is expected to save some time. Under this option the mass balance error is only written to the history file. No information is provided in which subroutine the problem occurred. |
| | 227 | |
| | 228 | 2 - err_act = 2 is recommended when developing and testing the model. Now the mass balance is explicitly checked in stomate.f90, stomate_lpj.f90 and all its subroutines. Under this option the mass balance error is written to the history file and if the mass balance is not closed, the warning message will indicate in which subroutine the problem likely originated. |
| | 229 | |
| | 230 | 3 - arr_act = 3 is recommended when having a problem with mass balance closure. The mass balance is explicitly checked in stomate.f90, stomate_lpj.f90 and all its subroutines. If a mass balance occurs, the model is stopped. |
