Forest Sector Carbon Calculator
Description
The forest carbon calculator is an interface and set of carbon models to help you examine how carbon stores in the forest sector change over time. The forest carbon calculator was developed by scientists at Oregon State University and the USDA Forest Service. Funding provided by Pacific Northwest Research Station, USDA Forest Service. This web interface will allow you to select different regions, past histories of disturbance and management as well as alternative futures. Currently, the calculator is parameterized for the Oregon East and West Cascades regions only. Calculations can be done for a single stand or for an entire landscape. Reports and time trend graphs on stores in the forest, in wood products (including bioenergy), and disposal can be generated.
Purpose and Scope
The Forest Sector Carbon Calculator is a tool to help learn about how carbon works in the forest sector; that is the forest itself and the carbon that is harvested from the forest. The Forest Sector Carbon Calculator integrates a number of kinds of software to gather information from users and to output results. But at its heart lies a model called LANDCARB that is designed to simulate the dynamics of living and dead pools of carbon in forest stands and landscapes. It also includes a submodel that estimates how harvested carbon is manufactured into forest products, as well as how these are used, and disposed. While there are many aspects of forest carbon dynamics LANDCARB 3.0 can be used to examine climate change, tree species, and succession. The version used in the Forest Sector Carbon Calculator is parameterized to allow the user to examine how natural disturbances such as wildfire and management activities such as timber harvest, site preparation, and artificial regeneration have on carbon dynamics. The user can examine carbon dynamics for a stand or for a landscape comprised of many stands. The results are presented in graphical form (which can be copied onscreen and pasted into a report) or as text output files that can be used to create custom graphs and analyzes. Output data represent either the store (or in the case of biofuels the offset) associated with a pool or the balance of a particular pool. Individual pools are combined at different levels so the user can look at an overall result or break it down into individual parts to gain deeper understanding. In addition to running various simulations the Forest Sector Carbon Calculator has a Tutorial Section to help users learn more about the model being used and how to run the Calculator. It also has results from a number of simulation experiments that will help users learn more about how carbon works in the forest sector. In some cases, it might not be what conventional wisdom suggests! This is not necessarily surprising as carbon in the forest sector involves many interactions and offsetting effects that are not so easy to grasp right off. The user will also find other resources such as reprints and computer code that may prove useful for those wishing to go into greater detail or to run more complicated simulations.
Use
This user's guide describes the third version of a model called LANDCARB that is designed to simulate the dynamics of living and dead pools of carbon in a forest landscape. LANDCARB 3.0 can be used to examine the effects that climate, tree species, succession, natural disturbances such as wildfire, and management activities such as timber harvest and salvage, site preparation, and artificial regeneration have on carbon dynamics at the landscape level. These results are presented in ASCII output files that can be used to examine the spatial and temporal pattern of carbon stores and fluxes. While this model also estimates the mass and volume of boles removed by harvest, it tracks the fate of this harvested material using a highly aggregated submodel. Another model should be used if one intends to examine changes in forest products mixes and uses (e.g., Harmon et al. 1996). Because LANDCARB 3.0 is designed to operate at the landscape level, it has incorporated finer levels of resolution within its computations using a meta-model approach. The meta-model approach is used to capture the overall response of more detailed simulation models of a phenomenon without all the computational burdens entailed in including the full model. LANDCARB 3.0 has been set up to mimic the stand level behaviors found in STANDCARB 2.0. This includes heterogeneity of species and ages, age-specific changes in the tree mortality rate as well as temporal lags associated with heart-rot and decomposition. LANDCARB 3.0 includes all the carbon pools that STANDCARB 2.0 does and all the same stand-level processes. To the degree possible the parameter files used by two models are the same, although they may be used in slightly different ways. Because the models are closely interrelated one can examine the effects of similar treatments at different spatial extents and expect comparable answers. For example, one might use STANDCARB 2.0 to test the effects of the interval between harvests, and LANDCARB 3.0 to test how landscape level carbon stores will change if the harvest intervals are implemented on a given landscape forest history. Temporally, LANDCARB 3.0 is a difference model that operates on an annual time step for all variables, except those used to estimate the effects of climate on tree establishment, growth, and decomposition. These climate related variables are calculated on a monthly time step. In addition, while disturbances are simulated annually, there are arbitrary semiannual timesteps that occur once the normal growth and decomposition related processes are addressed. Spatially, LANDCARB 3.0 is designed to simulate the dynamics of a number of cells within a landscape. Each cell represents the area occupied by a stand of trees, which can range from 0.25 to 100 ha. The stand of trees need not be homogeneous, because LANDCARB 3.0 uses a tree cohort structure to allow disturbances that remove part of each stand. The spatial location of these cohorts is not modeled directly, but the spatial interactions of cohorts is included. This approach allows the model to efficiently mimic the substand level disturbances that can be modeled in STANDCARB 2.0 without greatly imcreasing the computational demands. This users guide is designed to explain how to use the LANDCARB 3.0 model to investigate the effects of various types of forest management at the landscape level on live and dead carbon stores. We first provide an overview of the objectives and structure of the model. This is followed by a description of the modules used to run simulations. A brief summary of each of the major sections of the model is then described with particular attention to the equations used for critical calculations. Finally, the types and structures of the input and output files are defined. Before using the model a final word of caution is in order. LANDCARB 3.0 is a simulation model. As such, it represents our best representation of reality, but the results must be used with caution. There are many factors that may cause the projected results to deviate from what actually occurs. This is no different than the distinction between volume yield projections and the actual harvested volume. Bear in mind each simulation has a number of tacit assumptions, and when these are not met, the projected results may be entirely misleading. It may also be the case that the simulations are correct in a relative sense but not in an absolute sense. When interpreting results bear in mind that relative differences will always be more robust than absolute differences. Finally, it must be kept in mind that simulation models are only tools to be used primarily for planning or understanding how system works. They are not a substitute for actual measurements of the actual forest carbon stores of a particular landscape.
How to get it
Website: Forest Sector Carbon Calculator
Tool Restrictions and Limitations
Before using the Forest Sector Carbon Calculator a final word of caution is in order. LANDCARB 3.0 is a simulation model. As such, it represents our best representation of reality, but the results must be used with caution. There are many factors that may cause the projected results to deviate from what actually occurs. Bear in mind that every simulation model has a number of assumptions, and when these are not met, the projected results may be entirely misleading. It may also be the case that the simulations are correct in a relative sense but not in an absolute sense. When interpreting results bear in mind that relative differences will always be more robust than absolute differences. Finally, it must be kept in mind that simulation models are only tools to be used primarily for planning or understanding how systems work. They are not a substitute for actual measurements of the actual forest carbon stores of a particular stand or landscape.