Frequently asked questions

About the CBM-CFS3

Troubleshooting the CBM-CFS3

What are the current limitations of the CBM-CFS3?

Peatland carbon dynamics:

Although forested peatlands are recognized as an important contributor to carbon stocks in Canada, little is known about the impacts of management, disturbances, and climate change on fluctuations in water tables. Without the ability to predict changes in the water table for records in the peatland component of the forest inventory, it is not possible to predict the associated changes in carbon stocks in the peat component of the system. This issue is the subject of ongoing research. For example, for some boreal black spruce stands on peatlands, the model simulates the forest component of the ecosystem, but does not address the dynamics of the peat layer or the contribution of mosses to peat formation.

Climate change impacts on forest growth:

The CBM-CFS3 can simulate the effects of temperature changes on decomposition rates (Kurz and Apps 1999), but it does not address the impacts of changes in precipitation on decomposition. It also does not address the impacts of climate change on forest growth. Most applications of the CBM-CFS3 focus on the recent past or the next few decades. Refining the representation of climate change impacts is the subject of ongoing research.

The impacts of climate change on disturbance regimes:

These impacts are not predicted through process simulation, but users can implement them by providing scenarios with changes in disturbance regimes without explicit attribution to possible causes such as fire suppression or climate change.

Insect disturbances that cause reductions in growth rates:

Model components that address this issue have been implemented in a research version of the model and may become available in future versions of the CBM-CFS3.

Forest structure:

The CBM-CFS3 treats all stands as even-aged.  

Does the CBM-CFS3 account for carbon in shrubs and mosses?

Unless the user provides a volume-over-age curve for a shrub or moss component, it is not modeled in the CBM-CFS3.  At this time, the model disregards this carbon pool and operates under the assumption that its carbon content is neutral (i.e., as much carbon is lost annually through decay from this pool as is gained through new growth).

What disturbances are represented in the CBM-CFS3 and how are they represented?

The CBM-CFS3 contains a number of pre-defined disturbance types which represent the transfers of ecosystem carbon stocks that occur at the time of disturbance.  Users are able to create custom disturbance types to represent the ecosystem carbon transfers if an existing default is not sufficient.  Pre-defined disturbance types include:

  • Wild fire
  • Generic insect disturbance
  • Clearcut with slash-burn
  • Clearcut harvesting with salvage
  • Fire combined with salvage logging
  • Insects combined with salvage logging
  • Deforestation (various types corresponding to converted land use)
  • Afforestation
  • Natural non-forest rehabilitation
  • Partial cutting (50% removal)
  • Western jack pine budworm
  • Aspen defoliators
  • Spruce budworm (SBW) for young spruce stands (28 impact types) based on SBW decision support system
  • Spruce budworm for mature spruce stands (28 impact types) based on SBW decision support system
  • Spruce budworm for young fir stands (28 impact types) based on SBW decision support system
  • Spruce budworm for mature fir stands (28 impact types) based on SBW decision support system
  • Salvage logging after fire
  • Salvage logging after insects
  • Eastern hemlock looper (various degrees of defoliation)
  • Mountain pine beetle (various defoliation and mortality impact levels)
  • Spruce beetle (various defoliation and mortality impact levels)
  • Generic mortality (ranging from 5% to 95% mortality for creating custom disturbance types)
  • Commercial thinning (ranging from 10% to 85% volume removal)
  • Planting effects
  • Stand replacing natural succession
  • Clearcut harvesting without salvage

Is the CBM-CFS3 a spatial or an aspatial model?

The CBM-CFS3 is an aspatial model, i.e., forest stands are not spatially referenced. Users can track and report results for specific stands in their CBM-CFS3 project by attaching a unique classifier to each of their stands when they create their data import files or when entering stand information into the model.

Is this model endorsed by any organization(s) for forest carbon accounting?

The Government of Canada uses the CBM-CFS3 for reporting to the United Nations Framework Convention on Climate Change on greenhouse gas contributions from Canada’s forests.  This is done under Natural Resources Canada’s National Forest Carbon Monitoring, Accounting and Reporting System (NFCMARS). 

Is use of the CBM-CFS3 for forest carbon accounting a legal or regulatory requirement for any specific greenhouse gas agreements, forest certification, or sustainable forest management programs?

No.

What are the system requirements to run the CBM-CFS3?

To effectively run the CBM-CFS3, you will need:

  • a 1.2-Ghz processor or better;
  • a monitor capable of 1024 X 768 resolution (small fonts are highly recommended);
  • a minimum of 512 megabytes of RAM (RAM requirements scale with the size and complexity of the input data);
  • Windows XP, Windows Vista, Windows 7, or Windows 8;
  • Windows operating system language set to “English (Canada)” for the English version of the CBM-CFS3 and “French (Canada)” for the French version of the CBM-CFS3;
  • a hard drive with 1 gigabyte or more of available space;
  • Microsoft Data Access Components (MDAC) version 2.6 or better,
  • Microsoft .NET Framework version 1.1 redistributable package.
  • display DPI setting, set to “Normal size (96DPI)

What does the carbon pool structure of the CBM-CFS3 look like?

The carbon pool structure of the CBM-CFS3 displaying carbon flow through a forest ecosystem from the biomass pools (Foliage, Other, Merchantable stemwood, Coarse roots, Fine roots) to the above- and belowground dead organic matter (DOM) pools (Snag branches, Snag stemwood, Medium, Aboveground fast, Aboveground very fast, Aboveground slow, Belowground fast, Belowground very fast, Belowground slow), and from DOM pools to other DOM pools and the atmosphere.

The carbon pool structure of the CBM-CFS3  
AG=Aboveground  BG=Belowground  SW=Softwood  HW=Hardwood

Long description

The carbon pool structure of the CBM-CFS3
The carbon pool structure of the CBM-CFS3 displaying carbon flow through a forest ecosystem from the biomass pools (Foliage, Other, Merchantable stemwood, Coarse roots, Fine roots) to the above- and belowground dead organic matter (DOM) pools (Snag branches, Snag stemwood, Medium, Aboveground fast, Aboveground very fast, Aboveground slow, Belowground fast, Belowground very fast, Belowground slow), and from DOM pools to other DOM pools and the atmosphere.

Is the model source code open and available to users and software developers?

Not at this time.  If you wish to alter the design or algorithms of the CBM-CFS3 in order to meet your needs, please contact the carbon accounting team at the Canadian Forest Service to discuss and potentially collaborate.

In what languages are the CBM-CFS3 and its user’s guide available?

The CBM-CFS3 and its user’s guide are currently available in Canada’s two official languages, English and French, and Spanish. A Russian “beta version” of the model interface has also been developed. The design of the CBM-CFS3 has facilitated conversion of the graphic user interface to other languages. If you are interested in having the CBM-CFS3 and its user’s guide translated to another language, please contact the carbon accounting team at the Canadian Forest Service to discuss potential collaboration.

How is the CBM-CFS3 maintained, updated, and developed?

The carbon accounting team at the Canadian Forest Service is mandated to maintain, update and continue to develop the CBM-CFS3 software.  It is connected to the international science community to ensure that the science of forest carbon accounting is kept up to date in the model, and is connected to the international policy community to ensure that the model continues to meet international forest carbon reporting requirements.  As well, the carbon accounting team is connected to the international forestry community – those using the CBM-CFS3 – and continues to refine and develop the model to meet their needs.

Can the CBM-CFS3 be applied outside of Canada?

The CBM-CFS3, although developed for use in Canada, can be applied in other countries.  Because the model contains climate, decay, ecological, and timber merchantability parameters and data specific to Canadian terrestrial ecological zones and species, it is most easily adaptable to countries with similar climates and species.  To date, the CBM-CFS3 has been applied in over 25 countries. For more information about adapting the model for use in your country, contact the carbon accounting team at the Canadian Forest Service.

What is the smallest area the CBM-CFS3 can model?

The smallest area that can be modeled using the CBM-CFS3 is 0.1 ha.

Do I need to use a timber supply model to use the CBM-CFS3?

No.  For stand-level projects, the user can enter their data using the Stand-Level Project Creator, and for landscape-level projects, they can put their data into import files formatted for the CBM Standard Import Tool.  Consult the Operational-Scale Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) Version 1.2: User’s Guide for more information.

How long does it take to process a simulation?

Processing time for a CBM-CFS3 simulation will depend on the size and complexity of the user’s project and their computer hardware.  Having a computer processor greater than the minimum 1.2-Ghz and more than the minimum 512 megabytes of RAM will help speed up processing.  A small project (<5000 stands, 4 classifiers, 10 disturbance events per time step for 100 years) will take approximately 5 to 10 minutes to simulate.  A large project (>200,000 stands, 10 classifiers, 1,000 disturbance events per time step for 100 years) will take approximately 4-8 hours.

Is training in the use of the CBM-CFS3 available?

Once or twice a year (subject to funding), the carbon accounting team at the Canadian Forest Service delivers training workshops open to all interested participants.  Workshops are typically 3 days in length and involve presentations on the science of forest carbon accounting and hands-on training in the use of the model.  Workshops tend to be either directed towards Canadian or international users, but participation is open for either.  If you have downloaded the CBM-CFS3 or contacted the carbon accounting team at the Canadian Forest Service regarding training, you will be automatically notified when a workshop is available.  If you would like to be added to the notification list,contact the carbon accounting team.

Are materials available to help me learn how to use the CBM-CFS3 on my own?

Yes.  The user’s guide for the CBM-CFS3 has been published in PDF format and is available for free download.  The guide contains information about the model, system requirements, all of the model’s tools, and instructions on how to prepare input data and to use each of the tools.;

Users can also find instructional tutorials on how to use the model by clicking on “Tutorials” under the “Help” menu option in the main CBM-CFS3 window.

How were the volume-to-biomass equations used for each tree species in the CBM-CFS3 developed, and where can I obtain them?

The conversion factors and methods used by the CBM-CFS3 are based on the results of an ongoing Canadian Forest Service project at the Pacific and Laurentian Forestry Centres that is developing such conversion factors for application to the Canadian Forest Inventory (CanFI2001).  The conversion factors and algorithms are based on more than 1000 tree-level biomass regression equations compiled from the literature.  These have been applied to more than 11 million tree measurements from over 133,000 permanent sample plot data from across Canada.  A published report of the methods is available from the CFS Publications. The volume-to-biomass coefficients in the CBM-CFS3 were updated in early 2015, and a report on these updates is expected to be available at www.nfis.org later in 2015.

The CBM-CFS3 doesn’t have a data import tool for the timber supply model that I use; can one be developed?

The carbon accounting team at the Canadian Forest Service may develop new import tools for the CBM-CFS3 based on user requests and subject to funding and programmer resources.  The team is open to collaborative model development and model development suggestions.  If you want to request the development of a new import tool or collaborate to develop a new import tool, please contact the carbon accounting team.  In the meantime, those who do not use the Remsoft Spatial Planning System can use the CBM Standard Import Tool for operational-scale data imports, or the Stand-Level Project Creator for creating individual stands.

What is the difference between the aboveground and belowground slow DOM pools?

The belowground slow DOM pool consists of C from the very fast belowground DOM pool (which in turn came from a proportion of the fine root turnover), the fast belowground DOM pool (which in turn came from a proportion of the coarse root turnover), and the slow aboveground DOM pool (came from a biomixing rate).  The aboveground slow DOM pool consists of C from the very fast aboveground DOM pool (which in turn came from a proportion of the fine root turnover), the fast aboveground DOM pool (which in turn came from (a) a proportion of the coarse root turnover, (b) a proportion of branch snag decay, and (c) branch snag fall down), the medium DOM pool (which in turn comes from (a) a proportion of the stem snag decay and (b) stem snag fall down), and the black C pool (which is introduced during stand initialization when the fire disturbance matrix is applied). 

Does the CBM-CFS3 track carbon in forest products?

The CBM-CFS3 accounts for forest ecosystem carbon dynamics.  Although transfers of carbon are made to a “Forest Products” pool and users can track how much carbon was harvested from their land base, only inputs to this pool are tracked (i.e., the carbon dynamics of the forest products sector are not explicitly modeled).


What is the bare minimum of information required for a detailed forest inventory for input into the CBM-CFS3?

The bare minimum needed is an area stratified by age classes and forest type (where forest type is a set of user defined classifiers, one of which must identify the leading species).  Growth curves need to be identifiable by the same forest types that define the inventory.

Which CBM-CFS3 import tool should I use?

Which CBM-CFS3 import tool users should select will depend mainly on where their input data and information are coming from. Users whose input data are coming from Spatial Woodstock, other timber supply models, or other sources, can either use the CBM Standard Import Tool, which requires users to create standardized import files containing their data and information, or use the Stand-Level Project Creator, which requires the user to manually enter data and information for their project. Projects created using the Stand-Level Project Creator cannot contain more than 100 stands.

How many records can the CBM-CFS3 process?

Successful simulations containing approximately 1.4 million records distributed across some 100 disturbance groups (in that case, administrative management units), each of which comprised several ecological spatial units (for a total of nearly 800 spatial units) have been completed using the CBM-CFS3.

What is the minimum and maximum number of classifiers that I can use in the model to describe my stands?

Classifiers are user defined, and you can describe your stand with your own stand characteristics terminology.  The maximum number of classifiers that you can use is ten, and the minimum number is one; however, if you only use one, it must define the leading species.

Do the volume/age curves used as input for the CBM-CFS3 have to represent merchantable volume, and which should I use, gross merchantable volume curves or net?

The CBM-CFS3 calculates biomass components from merchantable volume.  Calculations are done using a national system of volume-to-biomass estimation models developed as part of Canada’s national forest inventory (Boudewyn et al. 2007).  Users should employ gross merchantable volume curves (i.e., volume inside the bark of the main stem, excluding tops and stumps, but including defective and decayed wood of trees or stands).  Standard provincial and territorial merchantability criteria are assumed by the volume-to-biomass estimation models that are built into CBM-CFS3.

Can a project I create with the CBM-CFS3 contain more than one management area/unit, and how do I identify this in my data?

Yes.  Simply add a classifier to your data that identifies management area/unit.  Once you have created and simulated your project, you can filter results by the management area/unit classifier you created.  If you have management areas/units in different administrative (province or territory) or ecological (terrestrial ecozone of Canada) boundaries, you should also consult the answer to the following question, “My project will have more than one ecological or administrative boundary, which import tool(s) can I use, and how do I prepare my input data to account for this?”

My project will have more than one ecological or administrative boundary; which import tool(s) can I use, and how do I prepare my input data to account for this?

The CBM Standard Import Tool should be used. When preparing your import files, you must include a classifier for ecological boundary (terrestrial ecozone of Canada) and administrative boundary (province or territory) in the description of each of your stands.  During the CBM-CFS3 data import process, in addition to identifying your leading species as a special classifier and mapping each of your species to those defined in the CBM-CFS3, you will need to identify administrative boundary and ecological boundary as special classifiers and map each of your types to those defined in the CBM-CFS3.

Can I use the CBM-CFS3 for forest certification reporting?

Yes.  Your project results from the CBM-CFS3 can be used to report on forest carbon indicators for various forest certification programs (i.e., CSA Z809, FSC or SFI).

What is an assumption in the CBM-CFS3 and how is it used?

There are fifteen assumption types in the CBM-CFS3: Simulation, Stand Initialization, CBM Run, Biomass Turnover, Climate, DOM Turnover, Disturbance Matrix, Disturbance and Management, Growth, Volume-to-Biomass, Growth multipliers, Disturbance multipliers, Nonforest initialization, Historic growth curves, and  Historic disturbance types assumptions.  When users create a project, a default assumption is created for each of these assumption types.  The default assumptions created are essentially names linked to either the user’s imported data or data assigned to the user’s project based on the administrative and ecological zone they select during data import.  For example, imported growth and yield curves would be linked to the default growth assumption.  Users can also create their own assumptions and link them to new data that they enter into their project in the CBM-CFS3.  A project must have at least one assumption of each type in order to be run in a simulation.  As discussed, one assumption of each type is created by default whenever users create a project, so that they may proceed immediately to execute a simulation and review results.

What is a disturbance matrix?

A disturbance matrix defines how carbon is transferred in the forest ecosystem from carbon pool to carbon pool for each terrestrial ecozone of Canada, following a specific natural or anthropogenic disturbance event. A disturbance matrix can be edited and new ones can be created.  

When I map my disturbance types to those modeled in the CBM-CFS3 during the data import process, I don’t see one similar to my disturbance type.  Can I set up a new default disturbance type in the CBM-CFS3, and what does this involve?

Yes.  Users can add a new default disturbance type using the Default Input Data Editor.  In this editor, it is recommended that users copy and rename an existing disturbance type (as opposed to adding a new one) that may have somewhat similar impacts on ecosystem carbon transfers, as this will result in the creation of linked disturbance matrices for each ecozone type, containing carbon matrix transfers identical to the original disturbance type selected.  Users can then make minor edits to their new disturbance matrices that they plan to use to better reflect how carbon will transfer in the forest ecosystem as a result of their new disturbance type.  Users can also simply add a new disturbance type and set up the disturbance matrices for it from scratch.

How many projects can I open at once in the CBM-CFS3?

One.

Can I conduct more than one simulation at a time in the CBM-CFS3?

Yes.  In the Simulation Scheduler, you can add more than one simulation at a time. They will be run sequentially.

I want to test the impact of a new harvest or disturbance plan on my forest carbon stocks and stock changes.  Is there a simple way to get an idea of what kind of impact it will have?

Using the Stand-Level Project Creator, create a project with a 1-ha stand of your most common forest type and apply the new harvest or disturbance plan to it.  Following simulation of the project, examine the impacts on your ecosystem carbon stocks and stock changes.  To get an idea of the impacts, multiply the results by the number of actual hectares covered by the forest type you selected, and compare these results to those you obtained for that same area under your original harvest or disturbance plan. 


I have encountered an error while installing or using the CBM-CFS3 and I have been unable to resolve it; what should I do?

Document the actions you were undertaking when the error occurred, and obtain a screen capture of the error (or document what the error message stated), and send this information to the carbon accounting team at the Canadian Forest Service.  Our team will attempt to diagnose the problem and will contact you with the solution or follow-up questions to resolve the problem.

When I use the model, some of the buttons and/or boxes in particular windows are missing when compared to figures of those windows in the CBM-CFS3 user’s guide or tutorials; what should I do?

First, make sure you are using the latest version of the model and user’s guide.  Next, contact the carbon accounting team with the name of the windows and names of any buttons or boxes that are failing to appear.  The cause may simply be the result of an update to the software that has not yet been documented, or perhaps the screen resolution and fonts selected under the display settings for your Windows operating system will require an adjustment.