Simulation of long-term forests in SWAT: Starting points and management

[James Dennedy-Frank]

Hello All,

I am looking to simulate a site with a long-term forest on it (including at the beginning of the simulation), and have run across a number of questions around how to start with a forest in place and how to correctly set management parameters for a forest. I know that questions about this have been asked in the past, but I couldn't find a consistent set of answers in looking through past posts, so I figured I'd put together a list of questions and hope that I can get them answered (or get references to them). If I can get a good set of answers to these I'd be happy to write up a small section on it for a wiki, as has been recently discussed in the Almendinger award thread.

As a note, I am using ArcSWAT2012 to set up the SWAT run, and running it using SWAT2012 through the SWAT-CUP 5 interface.

My first set of questions has to do with setting the .mgt file so that it starts with an established forest rather than starting a forest from seed.

1. My understanding is that the default forest settings for forest-type land use classifications (e.g., FRST, FRSD, FRSE) start from seed rather than from an established forest because IGRO=0. Is this correct?

2. If #1 is correct, then I believe that I can start with an established forest by changing IGRO = 1, setting PLANT_ID = 7,  and setting appropriate LAI_INIT, BIO_INIT, and PHU_PLT parameters. What would be appropriate parameter values? I am tempted just to set them to BLAI, BMX_TREES (corrected for units? BIO_INIT says [kg/ha] and BMX_TREES says [metric tons/ha], and 0, respectively, to basically set it as fully mature. This would be an odd pulse for a model starting on January 1, but I would hope that it would work its way through during the warmup period. Alternately, I might set them to some percentage of maximums to start with an almost mature forest.

3. Is there a tool developed to change these for appropriate HRU land use classifications? I am happy to build something to do it myself, but don't want to duplicate the effort if it already exists.

My next set of questions has to do with setting up the scheduled management operations component of the .mgt file so that they are appropriate for a forest that isn't being harvested (though it is undergoing seasonal senescence). 

4. Can I just set NROT=0 and set up no plant or harvest/kill operations so that the forest is responding only to the heat unit definitions for dormancy and growth, rather than having explicit plant/yield dates/HU settings?

5. If I can just set NROT=0 and no plant or harvest/kill operations, then I believe that the loss of biomass should just be BIO_LEAF, as set in the plant.dat (or crop.dat) file (in the case of FRSD, 0.0500). However I note that this is massively different from the HVSTI, which is 0.76 for FRSD, suggesting the loss of the majority of aboveground biomass. Is my understanding of this correct?

6. The default scheduled management operation for FRSD coming from ArcSWAT includes a harvest and kill operation, which doesn't make sense to me. Is there some default wherein a harvest and kill operation on a PLANT_ID = 7 (IDC of trees) just pulls away some of the biomass (either to yield or residue) but doesn't require starting at seed again, or is this simply a poor default from ArcSWAT?

6b. If there is a different default for PLANT_ID = 7 wherein a harvest and kill operation does not fully kill the treest, then is the plant operation for each year fine, just starting growth again from a previously established biomass?

6c. In the default harvest and kill operation for FRSD there is a setting of 0.00000 after the definition of the harvest and kill. This aligns vertically with what appears (based on counting decimal points) the HEAT UNIT count for the planting operation (though, at 2485, this seems a bit low), which suggests that it should be CNOP based on table 20-1 (on p. 259 of the SWAT 2012 I-O documentation) and the formatting segment on p. 271. That, however, makes little sense to me, so I thought it might be the HI_OVR, instead, which would be a more sensible setting for a forest (none of the biomass goes to harvest, rather it is left as residue). 

7. I am confused by the presence of the skip-a-year-operation code in the FRSD .mgt file. Does this mean that it only goes through the plant and harvest/kill (or, perhaps, not kill) operation every two years? Or does it just mean that it doesn't check the operation file again after doing the harvest/kill (or, perhaps, not kill) until January 1 of the next year?

Thank you all very much for your assistance and thoughtful responses, and I will work to figure this out and share the information with the community.

Best,

James

 

[James Dennedy-Frank]

Just wanted to bump this up. If anyone knows the appropriate ways to do this, please let me know. Alternately if you know who is working on simulating forested catchments using SWAT and so might have good suggestions, let me know and I will contact them directly.

I have confirmed that with the current default values both the LAI and biomass of forests (both FRSD and FRSE) are dropping to 0 each winter, which doesn't seem like reasonable behavior to me (the max LAI during the summer is around 3 and the biomass is around 20 kg/ha), although neither changes much even over a 30-year run, which is surprising). While the LAI of FRSD dropping to 0 makes sense, the FRSE shouldn't, it seems to me, and the biomass certainly shouldn't since that should consist of leaves plus lots of woody material.

By the way, can anyone clarify units here? BMX_TREES is listed as metric tons/ha, whereas BIOM is listed in kg/ha for daily values and tons/ha for monthly and annual values. Are we really supposed to use different units here, or is one of these a typo?

Thanks for the help.

Best,

James

[gangaram maharjan]

Hi James,

I saw your post in swat user group and come to know that you are interested to simulated the forest growth.I am also interested to simulated the forest growth in swat model for my phd work. So far i tried several ways to get the development of lai and bio mass. i got biomass and lai but i could not able to get yield in my work. The development of graphs for the forest ie tree crops like ochard is depicted as in this pic (3 yr simulation excluding 2 yr warm up)

To obtain this development the crop.dat values belong to this crop ie FRSD (7=crop id) is as follows 

   7  FRSD   7 (source from crop.dat from my project)

  15.00   0.76    5.00   0.05   0.05   0.40   0.95   0.99    6.00   3.50

  30.00   10.00   0.0015   0.0003   0.0060   0.0020   0.0015   0.0007   0.0004   0.0003

  0.010   0.0010   0.0020   4.00   0.750    8.00    660.00    16.00   0.0500   0.000

  0.050    40  1000.00   0.650   0.100

here BMX_TREES is 1000 metric tons/ha (plz suggest for this value) however the values in swat in-out put doc suggest for 30-50 metric tons/ha 

one of the management file (.mgt) that pertain to FRSD hru is as follows

 .mgt file Watershed HRU:121 Subbasin:6 HRU:16 Luse:FRSD Soil: ForSoil Slope: 0-9999 4/8/13 00:00:00 ArcSWAT 2009.93.7

               0    | NMGT:Management code

Initial Plant Growth Parameters

               1    | IGRO: Land cover status: 0-none growing; 1-growing

               7    | PLANT_ID: Land cover ID number (IGRO = 1)

            0.00    | LAI_INIT: Initial leaf are index (IGRO = 1)    note: do not have idea about this valus plz suggest 

            0.00    | BIO_INIT: Initial biomass (kg/ha) (IGRO = 1) note: do not have idea about this valus plz suggest 

            0.00    | PHU_PLT: Number of heat units to bring plant to maturity (IGRO = 1) note: do not have idea about this valus plz suggest 

General Management Parameters

            0.20    | BIOMIX: Biological mixing efficiency

           78.00    | CN2: Initial SCS CN II value

            1.00    | USLE_P: USLE support practice factor

            0.00    | BIO_MIN: Minimum biomass for grazing (kg/ha)

           0.000    | FILTERW: width of edge of field filter strip (m)

Urban Management Parameters

               0    | IURBAN: urban simulation code, 0-none, 1-USGS, 2-buildup/washoff

               0    | URBLU: urban land type

Irrigation Management Parameters

               0    | IRRSC: irrigation code

               0    | IRRNO: irrigation source location

           0.000    | FLOWMIN: min in-stream flow for irr diversions (m^3/s)

           0.000    | DIVMAX: max irrigation diversion from reach (+mm/-10^4m^3)

           0.000    | FLOWFR: : fraction of flow allowed to be pulled for irr

Tile Drain Management Parameters

           0.000    | DDRAIN: depth to subsurface tile drain (mm)

           0.000    | TDRAIN: time to drain soil to field capacity (hr)

           0.000    | GDRAIN: drain tile lag time (hr)

Management Operations:

               1    | NROT: number of years of rotation

Operation Schedule:

          0.110  1    7     40   1034.00000   0.00   342.00000 0.00   0.00  0.00

In my understanding when IGRO is 1 the operation schedule is not considered however i have plant/begin growing season is included as operation schedule. But based on operation schedule i have PHU as 1034  and LAI_INI as 0.0

I also tried deactivating initial plant cover as IGRO set as 0 which means activating the operation schedule which also give 0 yield with similar lai and biomass development. 

I hope you would have good suggestion for my figures for PHU, LAI_INI, BIO_INI and so on. If you have experience to get the yield let me know to improve the yield status from 0. 

Just for information my arc swat version is  SWAT Jun 01 2011    VER 2009/Rev. 481      

I hope you would reply me besides your busy schedule. 

Sincerely 

Ganga Ram Maharjan

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Ganga Ram Maharjan

Phd. Student,

University of Bayreuth, Universitaetsstrasse 30
NW1 Room 7.001 Pflanzen-Ökologie,

(Research: Land use change, sediment transport,water quality,crop production and  environmental trade off)

[James Dennedy-Frank]

Hi Ganga Ram,

Thanks for your note--I appreciate your input. 

I have to say that it's a bit hard to follow the figure you put in given the very small fonts, and it doesn't work well to save it either. Can you attach the figure with slightly larger fonts so that it can be more easily read and understood?

As far as I can tell, what you are getting is LAIs that vary from some minimum (0?) to a maximum (5?) each year, and a biomass that is ratcheting up each year. This definitely seems to me to be progress over the baseline management (which in SWAT 2012 includes a harvest/kill operation that brings biomass down to 0 each year.However, it looks like your ET (the blue line?) is dropping as LAI goes up each summer, which is surprising and counter-intuitive. However, I can't tell for sure given that I can't read the axes.

The variables that you seem to have changed from default in plant.dat (or crop.dat) are:

1. ALAI_MIN: 0.75 -> 0, which lets you get the LAI down to 0 in the winter. I'm not entirely certain if this is desired, however, because I'm not certain if the transpiration component of ET should really drop to 0 in the winter.

2. BIO_LEAF: 0.3 -> 0.05, which allows you to reduce the dropoff in biomass each winter. However, in some of the notes online (see, for example, question 267 in the recent SWAT FAQ), it suggests that mass is set as 80% woody growth and 20% leaves/needles. For a case like this, it seems like more that 5% of biomass should be dropped each year for consistency, and may be part of why the yield is so low.

3. MAT_YRS: 10 -> 40, which makes it take a longer time to get your plants to maturity take longer. However, note that you skip over this by overriding in the .mgt file.

In the .mgt file, it seems to me that you do two overlapping things when you should probably do only 1. First, you set IGRO=1, but without changing either LAI_INIT or BIO_INIT, but setting PHU_PLT to 0.0. If I understand correctly this then it starts the system growing at maturity (PHU_PLT = 0.0) but with both LAI and BIOM = 0.0. This doesn't seem real consistent to me. Second, however, when you do a planting you set CURYR_MAT, which means rather than a basic planting you are actually doing a transplanting of 40-year-old (that is, mature based upon MAT_YRS) trees with BIO_INIT of 342 kg/ha, but LAI_INIT of 0. These plants needs 1034 HUs to reach maturity. I'm not certain whether the IGRO or transplant systems are the effective ones, but it seems like that should be checked.

I would suggest that you run without warm-up years just for the purpose of understanding what is happening with the tree management. In particular, I think it would be interesting to see whether the transplant or the IGRO is in control in this case--when the HUs are at 0.110, does the BIOM jump to 342 kg/ha (the transplant happens, and is in control), or just continue on the same trend (IGRO happens and is in control). However, this happens before the 2 warm-up years have occurred, so it can't be seen in this plot. 

I'm still playing with ideas for BIO_INIT and LAI_INIT, although I'm tending towards setting some default value and assuming that it will get worked out in the warm-up years. 

I am finding that I often get a bit of nutrient stress with an existing forest, but with different reasons for P and N; are you seeing nutrient stress? The P stress occurs during the strong growth phase when LAI is increasing rapidly. This P stress is not an issue of P availability because it occurs even with constant fertilization, which shows a large buildup in the soluble P. Rather it seems to be an effect of the P uptake curve, as changing the ratios between PLTPFR(1), (2), and (3) seems to change the stress (but not the absolute values). I am wondering if this means that it it running through the whole uptake curve each year rather than being at the "mature" stage and so staying with PLTPFR(3) for the whole time during this stage.

The N stress does seem to occcur because of a lack of nitrogen. I haven't figured this one out yet, but I'm guessing that I can adjust for it by changing a bit about the residue behavior, keeping more of the N locally. 

I think that's it for about now. I'm sorry I don't have better answers, but I'm still working on this. Hopefully these thoughts are helpful, though, and we can get this figured out in the near future.

Best,

James

[gangaram maharjan]

Dear James,

Thank you very much for your nice reply. This time i tried to synthesize my all graphs in the ppt where you can zoom for better understanding. 

 In the previous work, the development of LAI and BIO mass was there as curve development and senescence(dormancy in every winter) with in a year. However i overlap my model with IGRO 1 and planting operation in .mgt file. LAI_INIT, BIO_INIT, PHU_PLT all 0 value ( when IGRO = 1) but in  Planting operation, there seems 40 yr old tree (ochard defined as tree in crop.dat) with 0 LAI_INIT, 342 BIO_INIT and 1034 PHU was planted which seems not realistic way in field level. It was difficult to say which one was considered (IGRO=1 or planting operation in .mgt file) for the LAI and BIO_Mass development. The yield was also also most zero(even there was development of lai and biomass) which i was trying to improve to get some yield value. 

So this time  i delete all the operation schedule in mgt file with the help of arc swat interface and try in several ways to see the development of LAI and bio mass with IGRO=1 setup lonely with different LAI_INIT, BIO_INIT and PHU_PLT values and also without warm up period. 

I have attache you the ppt where you can see

SLIDE1:  the graphs of LAI(black)- Left V axis and BIO mass(red) - right V axis development and ET (blue) at top- right inverse  axis and horizontal axis is time simulation (2007-2011) with out any warm up period as your suggestion

and other associated in put values in .mgt file for specific hru and crop.dat value is also presented in the respective slides for different scenarios.

My question for based on this slide 1: 

Q1.However as you said it could be visible that the development of LAI and Bio mass for these particular hrus starts based on my set values for LAI_INITI and BIO_INITI. In HRU 176 (ORCD) what might be the reason it starts keep on steady once it reached BLAI never senescence (LAI and BIO mass) (dormancy) in winter even ALAI is same ie 0 due to which i would expect to comes to 0 every year in winter as before and  same issue  for bio mass even having BIO_LEAF is set as 0.05

Q2. How can i get the yield improved from 0 to some figure?

SLIDE no 3: here the LAI_INITI, BIO_INITI and PHU_PLT are increased as indecated in slide. Here i can interpenetrate the curves, once it reached the highest lai 4 from 1 yr of simulation 2007  and stays same till end of 2007 then sharply drops down to almost 1.5. If you have idea of the LAI behavior l would like to get suggestion. 

SLIDE no 4: As you suggested before i have changed the ALAI and BIO_LEAF to 0.75 and 0.30 respectively to get the improved yield but not improved. Here the development of lai and biomass are similar trend as in slide no 3. 

SLIDE no 5: I cheek the over all water balance by using swatcheck for all these scenario they seems not changed and also for plant growth in which average yield is 0.1 Mha/ha this is also not due to ORCH land use its because of other land use of like RICE that i found from output.std if i am not wrong. My motivation for this work is to improve 0.1 Mha/ha contributed by ORCH land use.

My understanding in LAI development is, I guess the development of lai occurred until it reach the PHU_PLT where as limited by BLAI and senescence (dormancy) in winter has to occurred based on DLAI every year of simulation  which is not the case in this simulation. Let me know your experience in this regards.

After all these trails i was thing back to manipulate the management operation by setting IGRO=0, but i deleted all management operation  when i try for this work and i could not able to bring the management operation back in swat interface. just the interface could not high light the operation tab even i high light edit values. The swat interface appears as indicated in slide no 6. 

So far i have not gone through the nutrient stress which might be the reason for low yield. If you have some idea to work with these parameters i am happy to know. 

 I hope you would have some suggestion for this work. 

Sincerely yours

[James Dennedy-Frank]

Hi Ganga Ram,

All right--I'll see what I can do here. But remember that I'm just trying to figure this out too, so I'm not certain that I have all the answers. 

To start, my suspicion is that the reason you have basically no yield is that you do not have a harvest operation input in your management operations. If you look at the instructions, I believe that operation 7 is a yield without killing operation, which is probably the appropriate approach for an orchard. So you probably need to add one of those.

Q1. In the previous version you seemed to have appropriate seasonal cycles, with the biomass ratcheting up each year, but it was unclear whether that was started by the IGRO or the transplant command in management operations. What you see here, for the most part, is the start of growth without that seasonal cycle. It does seem, based on my work and this, that it is necessary to include a plant/grow term (1) in the management operations, even if starting out with the IGRO term.  However, by not putting a BIO_INIT or LAI_INIT into the management operation, I believe that it knows that the system is not a transplant but rather to stick with the IGRO values--you should be able to test this relatively easily. This is what I have seen with my work.

Q3. I'm not sure that I understand this behavior. There definitely seems to be something about reaching a threshold biomass (or maybe not reaching a threshold # of heat units?) that allows for this drop in LAI. I'm also not certain why it drops to 1.5 rather than 0.0, the ALAI_MIN. Perhaps it did not reach all the way through the dormancy for some reason, but I'm not certain.

Q5. I am not surprised that these don't change the water balance too much. The increased LAI should increase ET a little bit in the winter, but the reduced PET and possible water stress probably keep it from being too great. Again, in terms of yield I expect that you need to implement a harvest management operation--you're getting biomass, but won't get a yield if you don't harvest it, I think (I haven't worked with RICE, but things like AGRR (row crops) and hay do have harvest steps). 

I'm not sure why it won't let you edit the management operations--I would post that as a separate question to the ArcSWAT user group--I certainly have never seen that, personally. 

Hopefully we can get this figured out and working. Let me know if you have other questions.

Best,

James

[James Dennedy-Frank]

By the way, there's a really good discussion of this question on the ArcSWAT forum: https://groups.google.com/forum/#!searchin/arcswat/forest$2Fswitchgrass$20operations/arcswat/Ers3ZvYXe_A/a08C6x-ATIEJ

I'm not sure why this didn't come up the first time I searched for forest management on the forums, but it's the best thing put together so far, I think.

Best,

James

[Anna]

Dear James,
sorry to trouble you...but I need help to implement FRST in swat.
In my model (I used last version of swat v591) I have a lot of subbasins with landuse FRST.
I have implemented for example these FRST subbasin as below

Initial Plant Growth Parameters
               1    | IGRO: Land cover status: 0-none growing; 1-growing

               6    | PLANT_ID: Land cover ID number (IGRO = 1)
            5.00    | LAI_INIT: Initial leaf are index (IGRO = 1)
         1000.00    | BIO_INIT: Initial biomass (kg/ha) (IGRO = 1)
         1304.00    | PHU_PLT: Number of heat units to bring plant to maturity (IGRO = 1)

General Management Parameters
            0.20    | BIOMIX: Biological mixing efficiency

           65.02    | CN2: Initial SCS CN II value

            1.00    | USLE_P: USLE support practice factor
            0.00    | BIO_MIN: Minimum biomass for grazing (kg/ha)
           0.000    | FILTERW: width of edge of field filter strip (m)
Urban Management Parameters
               0    | IURBAN: urban simulation code, 0-none, 1-USGS, 2-buildup/washoff
               0    | URBLU: urban land type
Irrigation Management Parameters
               0    | IRRSC: irrigation code
               0    | IRRNO: irrigation source location
           0.000    | FLOWMIN: min in-stream flow for irr diversions (m^3/s)
           0.000    | DIVMAX: max irrigation diversion from reach (+mm/-10^4m^3)
           0.000    | FLOWFR: : fraction of flow allowed to be pulled for irr
Tile Drain Management Parameters
           0.000    | DDRAIN: depth to subsurface tile drain (mm)
           0.000    | TDRAIN: time to drain soil to field capacity (hr)
           0.000    | GDRAIN: drain tile lag time (hr)
Management Operations:
               1    | NROT: number of years of rotation
Operation Schedule:

You can see, that I haven't put anything in mgt2. The results is that  in the file output.mgt only the first subbasin with FRST has START and END DORM operations, while all other FRST subbasin has also PLANT operation.
Of consequence the biomass is very different in the first subbasin respect to all other subbasins.
It is very strange becouse the management is the same and in the file mgt2 there isn't plant operation.
What do you think about these problems?
How is the corrent management of FRST?
Thank you very much
Anna

[Olukunle Olanipekun Oladapo]

Good day
Please I am new to SWAT. I want to know the definition for the following land use codes:
FOEN
SHRB
SAVA
MIGS

Thank you

[Cristobal Puelma]

Hi, im doing the same with FRSE, but how I can see the LAI in time series? in what file?

El sábado, 31 de agosto de 2013, 14:39:11 (UTC-3), ganga ram maharjan escribió:

Hola James,

Vi su publicación en el grupo de usuarios swat y me enteré de que está interesado en simular el crecimiento del bosque. También estoy interesado en simular el crecimiento del bosque en modelo swat para mi trabajo de doctorado. Hasta ahora probé varias formas de obtener el desarrollo de lai y la bio masa. obtuve biomasa y lai pero no pude obtener rendimiento en mi trabajo. El desarrollo de gráficos para el bosque, es decir, cultivos de árboles como el huerto, se representa como en esta foto (3 años de simulación excluyendo 2 años de calentamiento)

Para obtener este desarrollo, los valores de crop.dat pertenecen a este cultivo, es decir, FRSD (7 = id de cultivo) es el siguiente 

   7 FRSD 7 (fuente de crop.dat de mi proyecto)

  15,00 0,76 5,00 0,05 0,05 0,40 0,95 0,99 6,00 3,50

  30,00 10,00 0,0015 0,0003 0,0060 0,0020 0,0015 0,0007 0,0004 0,0003

  0.010 0.0010 0.0020 4.00 0.750 8.00 660.00 16.00 0.0500 0.000

  0.050 40 1000.00 0.650 0.100

aquí BMX_TREES es de 1000 toneladas métricas / ha (por favor sugiera este valor), sin embargo, los valores en swat in-out ponen doc sugieren 30-50 toneladas métricas / ha 

uno de los archivos de administración (.mgt) que pertenecen a FRSD hru es el siguiente

 .mgt file Cuenca hidrográfica HRU: 121 Subcuenca: 6 HRU: 16 Luse: FRSD Suelo: ForSoil Pendiente: 0-9999 4/8/13 00:00:00 ArcSWAT 2009.93.7

               0 | NMGT: código de gestión

Parámetros iniciales de crecimiento de la planta

               1 | IGRO: estado de cobertura de la tierra: 0-ninguna creciendo; 1-crecimiento

               7 | PLANT_ID: Número de identificación de la cobertura del terreno (IGRO = 1)

            0.00 | LAI_INIT: hoja inicial es índice (IGRO = 1)     nota: no tengo idea acerca de este valus por favor sugiera 

            0.00 | BIO_INIT: Nota inicial de biomasa (kg / ha) (IGRO = 1) : no tengo idea acerca de este valus por favor sugiera 

            0.00 | PHU_PLT: Número de unidades de calor para llevar la planta a su madurez (IGRO = 1) nota: no tengo idea acerca de este valus por favor sugiera 

Parámetros de gestión general

            0.20 | BIOMIX: Eficiencia de mezcla biológica

           78.00 | CN2: valor inicial SCS CN II

            1.00 | USLE_P: factor de práctica de soporte USLE

            0.00 | BIO_MIN: biomasa mínima para pastoreo (kg / ha)

           0.000 | FILTERW: ancho del borde de la banda de filtro de campo (m)

Parámetros de gestión urbana

               0 | IURBAN: código de simulación urbana, 0-none, 1-USGS, 2-buildup / washoff

               0 | URBLU: tipo de tierra urbana

Parámetros de gestión de riego

               0 | IRRSC: código de riego

               0 | IRRNO: ubicación de la fuente de riego

           0.000 | FLOWMIN: flujo mínimo en la corriente para derivaciones de irr (m ^ 3 / s)

           0.000 | DIVMAX: desviación máxima de riego desde el alcance (+ mm / -10 ^ 4m ^ 3)

           0.000 | FLOWFR: fracción de flujo permitida para irrigar

Parámetros de gestión de desagüe

           0.000 | DDRAIN: profundidad al drenaje del azulejo subsuperficial (mm)

           0.000 | TDRAIN: tiempo para drenar el suelo a la capacidad de campo (hr)

           0.000 | GDRAIN: tiempo de latencia del azulejo de drenaje (hr)

Operaciones de gestión:

               1 | NROT: número de años de rotación

Horario de operación:

          0.110 1 7 40 1034.00000 0.00 342.00000 0.00 0.00 0.00

Según entiendo, cuando IGRO es 1, el cronograma de operación no se considera, sin embargo, tengo planta / comienzo, la temporada de crecimiento se incluye como cronograma de operación. Pero basado en el programa de operación, tengo PHU como 1034 y LAI_INI como 0.0

También traté de desactivar la cubierta vegetal inicial, ya que el IGRO se estableció como 0, lo que significa que se activó el programa de operación, que también da 0 rendimiento con un desarrollo similar de lai y biomasa. 

Espero que tengas una buena sugerencia para mis cifras para PHU, LAI_INI, BIO_INI y más. Si tiene experiencia para obtener el rendimiento, hágamelo saber para mejorar el estado de rendimiento de 0. 

Solo para información mi versión de swat de arco es SWAT Jun 01 2011 VER 2009 / Rev. 481      

Espero que me respondas además de tu apretada agenda. 

Sinceramente 

Ganga Ram Maharjan

El martes 20 de agosto de 2013 a las 2:39 a.m., James Dennedy-Frank < pj ... @ stanford.edu > escribió:

Hola a todos,

Estoy buscando simular un sitio con un bosque a largo plazo (incluido al comienzo de la simulación), y he encontrado una serie de preguntas sobre cómo comenzar con un bosque en el lugar y cómo establecer correctamente los parámetros de gestión para un bosque. Sé que se han formulado preguntas sobre esto en el pasado, pero no pude encontrar un conjunto coherente de respuestas al revisar las publicaciones anteriores, así que pensé en hacer una lista de preguntas y esperar poder responderlas. (u obtener referencias de ellos). Si puedo obtener un buen conjunto de respuestas, me gustaría escribir una pequeña sección para una wiki, como se discutió recientemente en el hilo del premio Almendinger.

Como nota, estoy usando ArcSWAT2012 para configurar la ejecución SWAT y ejecutarla usando SWAT2012 a través de la interfaz SWAT-CUP 5.

Mi primer conjunto de preguntas tiene que ver con establecer el archivo .mgt para que comience con un bosque establecido en lugar de comenzar un bosque desde la semilla.

1. Entiendo que la configuración forestal predeterminada para las clasificaciones de uso de la tierra de tipo forestal (p. Ej., FRST, FRSD, FRSE) comienza desde la semilla en lugar de desde un bosque establecido porque IGRO = 0. ¿Es esto correcto?

2. Si el # 1 es correcto, entonces creo que puedo comenzar con un bosque establecido cambiando IGRO = 1, estableciendo PLANT_ID = 7 y estableciendo los parámetros LAI_INIT, BIO_INIT y PHU_PLT apropiados. ¿Cuáles serían los valores de parámetros apropiados? Tengo la tentación de ponerlos en BLAI, BMX_TREES (corregido para las unidades? BIO_INIT dice [kg / ha] y BMX_TREES dice [toneladas métricas / ha], y 0, respectivamente, para establecerlo básicamente como completamente maduro. Esto sería una pulso impar para un modelo que comienza el 1 de enero, pero espero que funcione durante el período de calentamiento. Alternativamente, podría establecer un porcentaje de máximos para comenzar con un bosque casi maduro.

3. ¿Existe una herramienta desarrollada para cambiar estos para las clasificaciones apropiadas de uso de la tierra de la HRU? Me complace construir algo para hacerlo yo mismo, pero no quiero duplicar el esfuerzo si ya existe.

Mi siguiente serie de preguntas tiene que ver con la configuración del componente de operaciones de administración programadas del archivo .mgt para que sean apropiadas para un bosque que no se está recogiendo (aunque está experimentando senescencia estacional). 

4. ¿Puedo simplemente configurar NROT = 0 y configurar ninguna planta o operaciones de cosecha / muerte para que el bosque responda solo a las definiciones de unidades de calor para la latencia y el crecimiento, en lugar de tener configuraciones explícitas de planta / rendimiento / HU?

5. Si solo puedo establecer NROT = 0 y no hay operaciones de planta o de cosecha / muerte, entonces creo que la pérdida de biomasa debería ser BIO_LEAF, como se establece en el archivo plant.dat (o crop.dat) (en el caso) de FRSD, 0.0500). Sin embargo, observo que esto es masivamente diferente del HVSTI, que es 0.76 para FRSD, lo que sugiere la pérdida de la mayoría de la biomasa aérea. ¿Lo entiendo bien?

6. La operación de administración programada por defecto para FRSD proveniente de ArcSWAT incluye una operación de captura y muerte, lo cual no tiene sentido para mí. ¿Existe algún defecto en el que una operación de captura y muerte en un PLANT_ID = 7 (IDC de árboles) simplemente extrae parte de la biomasa (ya sea para rendimiento o residuo) pero no requiere comenzar de nuevo en la semilla, o es simplemente un pobre predeterminado de ArcSWAT?

6b. Si hay un valor por defecto diferente para PLANT_ID = 7 en el que una operación de cosecha y muerte no mata por completo al máximo, entonces ¿la operación de la planta para cada año está bien, comenzando nuevamente el crecimiento de una biomasa previamente establecida?

6c. En la operación de corte y muerte predeterminada para FRSD, hay una configuración de 0.00000 después de la definición de la cosecha y muerte. Esto se alinea verticalmente con lo que parece (basado en el recuento de puntos decimales) el recuento de la UNIDAD DE CALOR para la operación de plantación (aunque, en 2485, esto parece un poco bajo), lo que sugiere que debería ser CNOP basado en la tabla 20-1 (en p .259 de la documentación SWAT 2012 IO) y el segmento de formato en p. 271. Eso, sin embargo, tiene poco sentido para mí, así que pensé que podría ser el HI_OVR, en cambio, lo que sería un entorno más sensato para un bosque (ninguna parte de la biomasa se destina a la cosecha, sino que queda como residuo). 

7. Estoy confundido por la presencia del código de operación omitir-un-año en el archivo FRSD .mgt. ¿Esto significa que solo pasa por la operación de planta y cosecha / muerte (o, quizás, no matar) cada dos años? ¿O simplemente significa que no verifica el archivo de operación nuevamente después de realizar la cosecha / muerte (o, quizás, no matar) hasta el 1 de enero del próximo año?

Muchas gracias a todos por su asistencia y respuestas reflexivas, y trabajaré para resolver esto y compartir la información con la comunidad.

Mejor,

James

 

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Ganga Ram Maharjan

Doctor en Filosofía. Estudiante,

Universidad de Bayreuth, Universitaetsstrasse 30
NW1 Sala 7.001 Pflanzen-Ökologie,

(Investigación: cambio en el uso de la tierra, transporte de sedimentos, calidad del agua, producción de cultivos y comercio ambiental)