Difference between revisions of "Implementing forest thinning/insect mortality"
| Line 37: | Line 37: | ||
exactly as they would for the previous case. | exactly as they would for the previous case. | ||
<p><b>redefine_world_thin_snags</b></p> | <p><b>redefine_world_thin_snags</b></p> | ||
| − | This option should be used when you want to remove | + | This option should be used when you want to remove biomass but |
| − | leave standing dead (snags), for example to mimic insect defoliation or | + | leave standing dead (snags), for example to mimic mortality from insect defoliation or |
| − | + | drought. Biomass C and N pools are reduced based | |
| − | on the | + | on the fractions specified (as in the thin_remain option above) except livestem C and N |
| − | pools are transferred to deadwood | + | pools are transferred to deadwood C and N instead of CWD. |
<br><br> | <br><br> | ||
Example tec event: | Example tec event: | ||
Latest revision as of 10:42, 18 October 2012
Redefines for Forest Thinning and Insect Mortality
There are a few options that can be used as tec events to force biomass pool changes that mimic forest thinning or insect mortality. Use the commands below in your tec file at a specified date similar to the way you implement a redefine, so you will need a corresponding redefine world file at the same specified date.
redefine_world_multiplier
Whatever value you put in the redefine file will be multiplied to the
existing worldfile value. So, for example, if you have a 0.75 in the
cs_leafc slot in the redefine file, the leaf carbon value in the
worldfile will be multiplied by 0.75.
redefine_world_thin_remain
Only cover fraction, gap fraction, and the main carbon pool variables
(cs_pool, cs_leafc, cs_dead_leafc, cs_live_stemc, cs_dead_stemc,
cs_live_crootc, cs_dead_crootc, cs_frootc) will be read in from the
redefine file (all other values will be ignored). For cover fraction
and gap fraction, the value in the redefine file will become the value
in the new worldfile (i.e., how the main "redefine_world" routine
works... if you put a 0.3 in the redefine file the new worldfile value
will be 0.3). For the C-pool values, the values in the redefine file
should be the fraction of those pools you want "thinned", or removed
from the live biomass pools. The corresponding N-pool values will be
automatically removed and both the C and N removed fractions will be
distributed to the appropriate litter and CWD pools. So, for example,
you might want to run a thinning routine that "thins" all biomass by
0.25 and changes the gap fraction to 0.25. Your redefine file would
have 0.25 for all the above listed variables except cover fraction,
and the resulting new worldfile will show 75% of the pre-redefine C
and N pools, with the missing 25% C and N moved to the litter and CWD
pools. Of course, you can also vary what fraction of leaf versus stem
versus root C (and corresponding N) you want to remove, and can change
these fractions across space.
redefine_world_thin_harvest
Works the same as above, but the aboveground C and N fractions are "harvested" (e.g., removed from the live biomass pools but not added into the litter and CWD pools) while the belowground C and N fractions are removed and added to the litter and CWD pools as in the redefine_world_thin_remain option. The user sets the redefine file exactly as they would for the previous case.
redefine_world_thin_snags
This option should be used when you want to remove biomass but
leave standing dead (snags), for example to mimic mortality from insect defoliation or
drought. Biomass C and N pools are reduced based
on the fractions specified (as in the thin_remain option above) except livestem C and N
pools are transferred to deadwood C and N instead of CWD.
Example tec event:
1997 7 2 1 redefine_world_thin_harvest
Example stratum section of a template file used to create a (spatially varying) thinning redefine world. The cfrac and gap maps contain the values you want to set as your cover and gap fractions, respectively, and the thin map contains the values you want to set as your thinning fractions. You can use multiple thin maps to change pools by different fractions.
_stratum patch.fullveg 1
veg_default_ID value -9999
cover_fraction mode cfrac
gap_fraction mode gap
root_depth value -9999
snow_stored value -9999
rain_stored value -9999
cs_pool mode thin
cs_leafc mode thin
cs_dead_leafc mode thin
cs_leafc_store value -9999
cs_leafc_transfer value -9999
cs_live_stemc mode thin
cs_livestemc_store value -9999
cs_livestemc_transfer value -9999
cs_dead_stemc mode thin
cs_deadstemc_store value -9999
cs_deadstemc_transfer value -9999
cs_live_crootc mode thin
cs_livecrootc_store value -9999
cs_livecrootc_transfer value -9999
cs_dead_crootc mode thin
cs_deadcrootc_store value -9999
cs_deadcrootc_transfer value -9999
cs_frootc mode thin
cs_frootc_store value -9999
cs_frootc_transfer value -9999
cs_cwdc value -9999
epv.prev_leafcalloc value -9999
ns_pool value -9999
ns_leafn value -9999
ns_dead_leafn value -9999
ns_leafn_store value -9999
ns_leafn_transfer value -9999
ns_live_stemn value -9999
ns_livestemn_store value -9999
ns_livestemn_transfer value -9999
ns_dead_stemn value -9999
ns_deadstemn_store value -9999
ns_deadstemn_transfer value -9999
ns_live_crootn value -9999
ns_livecrootn_store value -9999
ns_livecrootn_transfer value -9999
ns_dead_crootn value -9999
ns_deadcrootn_store value -9999
ns_deadcrootn_transfer value -9999
ns_frootn value -9999
ns_frootn_store value -9999
ns_frootn_transfer value -9999
ns_cwdn value -9999
ns_retransn value -9999
epv_wstress_days value -9999
epv_max_fparabs value -9999
epv_min_vwc value -9999
n_basestations value -9999
