|Summary||On forest carbon cycle||
How to run
|General description||Examples for model output||
In order to assess carbon sequestration, one needs either field measurements, or models, or both. CASMOFOR can be used if no field measurements are available, or if they cannot be taken, e.g. when predictions are to be made. Such predictions are, e.g., necessary when planning afforestations. The aims of afforestation programs may be numerous, and one aim can be sequestering carbon. CASMOFOR was designed to help users estimate the carbon sequestration potentials of various afforestation programs. By making it possible to quickly compare different variants or options, CASMOFOR is an ideal decision supporting tool.
One needs a complete modeling of the carbon cycle if carbon sequestration is to be estimated correctly and accurately. In the system of forests and forestry, there are many pools (like biomass, dead wood biomass, wood products, soil etc.), and their carbon content is increased and reduced by many processes (e.g., growth, mortality, timber harvest etc.). The overall resultant of these processes change the overall carbon content of the system, since this system is open: it can absorb and emit carbon. Depending on the processes involved, the overall carbon content of the whole system can either increase (in which case the system removes carbon from the air) or decrease (when the system emits carbon to the air).
The ultimate objective of using the model is to estimate how much carbon is removed from, or emitted to, the air by the system. Thus, the focus of the model is not any traditional characteristics of the forests, such as the tree volume, but the amount of carbon in all pools and processes, i.e. the carbon cycle of forests and forestry. Therefore, the amount of all substances that contain carbon in various pools (e.g., biomass, soil) and that pass through these pools by many processes is converted to, and is handled as, amounts of carbon.
However, there are many types of pools and very complicated processes in a forestry system. These together with the spatial dimensions and spatial diversity of pools, and the time scale of the processes render it very difficult to asses the amounts of carbon in the various parts of the system over time. This difficulty is recognized by CASMOFOR, which was designed to predict the amount of carbon fixed by the forest. The model is based on inevitable simplification, which, however, does not pretend to be able to replace measurements when it is possible at all. On the other hand, CASMOFOR was designed to follow a stand after its establishment, and to provide estimates, after several years or decades of growing, for the amount of carbon actually fixed.
CASMOFOR does not pretend and attempt to be as scientific as theoretically possible. Rather, it focuses on practical approaches, by which practical and feasible estimates can be made and which concentrate on the most important pools and processes, i.e. those where the most carbon can be found., and upon which we may have any effect of considerable scale. The ultimate aim of forestations in terms of carbon is to fix air carbon and to keep it within the forestry system in the medium term (i.e. over several decades). Therefore, those pools and processes are of greatest importance where most carbon can be found at this time scale.
Because of the above, not all processes and pools are modeled with the same level of accuracy (or uncertainty). "Well" modeled processes and pools are the ones whose modeling is developed best and where most data (constants, functions, empirical values) are available. Attempts were made to incorporate all bits of information in the biological part of the model that are available in the literature so that modeling of the biological processes, which play the most important role in the system, is as accurate as possible. In addition, an attempt was made throught developing this help to document all important information on the whole model, and to indicate the accuracy/uncertainty of various modeling methods for the user to be able to judge the level of understanding that could be used in the model.
As it was noted above, CASMOFOR was designed so that it can be used for modeling the carbon cycle of forestation programs in Hungary. This means that all information stored in the model are for Hungarian species and site conditions (see specifications at the description of the respective pools and processes below). Although there are many models worldwide that are currently used for similar purposes (e.g. CO2FIX), their parametrization may be difficult because of their structure that is not appropriate to use with data available for the Hungarian conditions. CASMOFOR can be regarded as the model that is ideal for the Hungarian conditions because of its structure and parameters that was tailored for Hungarian conditions.
However, if the forestry system (e.g. thinning regimes, growth data etc.) is similar in another country, and only data are different, the structure of CASMOFOR can be used in this country so that data in the model are replaced with those that are used in that country.
The information content of the model (i.e. the "knowledge base", including growing characteristics of various species, thinning regimes, biomass expansion factors etc.) is stored in one file. This single file (kb.xls) contains growth data, expressed as tC/ha, and derived from growth data expressed as m3/ha*yr, biomass expansion factors (BEF, see details in the description of the model) and carbon content. The file also contains thinning regime data (timing and intensity of thinnings). Together with user.xls, which is used to provide the model with structural data (e.g. area or carbon content by species) of any forest that is present at the start of running the model, all files were designed so that the user itself can modify the data to fit them to actual afforestation situations.
Please note that, under the Hungarian conditions, the intent is that the user changes some data in kb.xls only if better data are available. For other countries, it is possible and easy to modify existing data or include new ones. Since CASMOFOR is already parametrized for the Hungarian conditions, modeling the carbon cycle of Hungarian forests can be better done by CASMOFOR than by any other model.
Scenario specific data, like area and/or biomass data, must be set in user.xls for some specific scenarios. Should the user want to replace/modify any data in the knowledge base, originally specific to the general Hungarian forestry conditions, please contact the developer of CASMOFOR, Zoltan Somogyi, how to do it.)
It must also be noted that some processes (e.g. soil preparation before planting, or erosion before planting or after clearcut etc.) that are not part of the normal afforestation system from planting to final cut are not modeled in CASMOFOR. Although these processes may be important sources of emissions (e.g. much carbon can be emitted from the soil during ploughing), they are outside the scope of CASMOFOR, are very roughly modeled, and are only modelled to get a rough idead of how important these processes could be with regard to the total sequestration of an afforestation system.
The flowchart of the carbon fluxes (processes) and pools of a typical Hungarian forestry system can be seen below. Help on any process or pool can be obtained either by looking for them in this help system, or by clicking on the approppriate part of the flowchart when running CASMOFOR, where the flowchart is also shown.
CLICK ON THE FIGURES TO GET HIGHER ONES
CASMOFOR is an accounting-type of model. It models many processes and pools based on the physical or biological processes in the forests, then sums them up. It accounts for every molecule of carbon dioxide that enters or leaves the system.
The various parameters, the structure of the model (pools, processes, external forces etc.), and information on accuracy and sources of error can be found in the detailed description of the model.
Some general characteristics of the model are the following:
Note that CASMOFOR was programmed as a system of MS Excel based spreadsheets by using MS Visual Basic (for Excel). The intent with all this was that (i) the use of the system is user-friendly, (ii) the parametrization of the model is easy for the user, (iii) both the structure of the system and parameters are transparent, and (iv) the whole system can easily be checked, fixed and developed further.
Finally, note also that great effort was made to document the model (its structure and knowledge base, all pools and processes etc.) so that the model is transparent, and that any modifications or development can later be made by either the author or users.
New in Version 4 compared to Version 3:
New in Version 3 compared to Version 2:
This webpage was last modified by Zoltan Somogyi 29 June 2014.