1. GLOBE Carbon Cycle: Modeling Forest Ecosystems
Sarah Silverberg, Rita Freuder
University of New Hampshire
Introductions
- project is housed at UNH
- working in collaboration with the Czech Republic, both Charles University and their major Education/Outreach Organization TEREZA
- our project is also part of GLOBE

2. Outline The GLOBE Carbon Cycle Project Modeling
Biomass Accumulation Model
Modeling with iSee Systems
Activity: Run the model
Learn about one activity that can be done using this model
Activity: Comparing Collected Data with Model Results

3. Carbon Cycle Project Goals
Students will…
Learn why carbon is an important element in ecosystems, and how it cycles through ecosystems.
Gain skills in current carbon cycle research techniques.
Increase their ability to critically think about problems.
Understand the nature of science research.
GLOBE Program
- GLOBE is an international K-12 science education program that unites students, teachers and scientists in the study of the Earth
- GLOBE has 3 program goals:
o Improve science education
o Increase scientific understanding of the Earth as a system
o Enhance the environmental awareness of individuals worldwide

4. Proposed Activities to Meet Goals
4 Major Categories:
Modeling
Classroom Experiments
Field Measurements
Remote Sensing Toolkit
Proposed Activities
- to meet these goals we have set out 4 categories of activities that together embody the steps that a scientist would go through if they were studying the carbon cycle
- The major categories are: modeling, field measurements, a remote sensing toolkit for looking at and analyzing images, and an classroom experiments
- when the project is fully developed these activities will be linked in a variety of ways

5. Modeling Introduces students to the use of models in science
Learn how carbon is stored and transferred at the ecosystem and global level
Understand ways that carbon can change with a change in environmental conditions
Connection to field collected data

6. globecarboncycle.unh.edu Website: Updates and Information

7. What is a Model? *mod·el (n).
The American Heritage® Dictionary of the English Language, Fourth Edition
*mod·el  (n).
1. A small object, usually built to scale, that represents in detail another, often larger object.
2. A preliminary work or construction that serves as a plan from which a final product is to be made.
3. A schematic description of a system or phenomenon that accounts for its known or inferred properties and may be used for further study of its characteristics.
4. One that serves as the subject for an artist, especially a person employed to pose for a painter, sculptor, or photographer.
5. A person employed to display merchandise, such as clothing or cosmetics.
What is a Model?
- Before we can discuss any more about the carbon model specifically, in my experience it is better to start at the beginning, especially because this is likely where all of your students will start
- What do you think of when you hear model? What do you think your students will think of?
- There are many definitions of a model, but most of these do not accurately reflect the type of models we use to study science

8. Better Working Definitions
Models are tools and concepts that help us understand, explain, and predict systems that are too complex or difficult to observe, or to comprehend on our own. --
Models are simplifications of reality. --
“The most useless scale for a road map is 1:1”

9. Why Use a Model?
Synthesize existing knowledge in ways not possible using human CPU (Cranial Processing Unit).
Forecast future conditions, often with policy- relevant goals.
Examine the fundamental behavior of a system.
Identify gaps in current knowledge and to guide future research.
Generate hypotheses (as opposed to predictions).
“The purpose of models is not to fit the data but to sharpen the questions”. - S. Karlin

10. A “Box and Arrow” or “Pool and Flux” model
Models Don’t Need to be Complex to be Useful
A “Box and Arrow” or “Pool and Flux” model
STANDING STOCK
(Pool, Reservoir)
INPUTS
OUTPUTS
Flux
Models don’t have to be complex to be useful
-it is most important to remember that although the subject matter that you are dealing with may be complex, the model you create to describe that subject can be simple
-Everyone can MODEL!!!
oOften all you need to know are the basic relationships between parameters and some simple math, addition, subtraction, multiplication, division
-Here we are looking at a box and arrow model
oThe box is the stock, reservoir or pool
oAnd the arrows are the fluxes, the inflow to the pool and the outflow from
-Residence time is the amount of time that material remains in a pool
-And the turnover rate is the fraction of material in a pool that enters or leaves in a given time
-these two things become particularly important when you look at more complex cycles
Residence Time: the amount of time material remains in a pool
Turnover Rate: the fraction of material in a pool that enters or leaves in a specified amount of time

11. (Mortality + Woody Litter)
1 Box Forest Biomass Model
STANDING STOCK (Pool)
Forest Biomass
INPUTS
(Wood Growth)
OUTPUTS
(Mortality + Woody Litter)
Flux
~400 g/m2 * yr
~2% / year
OUTPUT = (?)
2% per year
(Current Biomass * 0.02)
1 Box Forest Biomass Model
-Before students will be able to understand modeling something complex such as the global carbon cycle they will need to understand how modeling works when there is only 1 pool involved.
-This 1 box model is focused on the change of forest biomass over time, the inputs and outputs are based on average measured values for a forest in Northern New Hampshire
-Here the pool is forest biomass
-The input is wood growth also called wood production
oWood production is a function of the concentration of nitrogen in leaves
oFoliar nitrogen varies generally by tree type here open circles are coniferous trees and closed circles are deciduous trees, by specific tree species, and also by other environmental factors (temperature, precipitation)
oSo although a similar relationship exists between wood production and canopy N concentration in most ecosystem, the slope of the line will be different
oIn this case a typical foliar N value is approximately 2%, which means we have a wood production rate of 400 g/m2/yr
-The output is wood loss due to tree mortality or production of woody litter, which is the amount of branches that come down each year because of old age, disease and wind-throw
orather than being a constant flux like wood growth, wood loss is a proportional flux
othis means the amount of wood loss is dependent on the total amount of wood in the forest biomass pool
ofor New Hampshire wood loss is estimated to be 2% per year

12. 1 Box Forest Biomass Model
Remember 45-50% of biomass by weight is carbon!!!
1 box forest biomass-graph
-so what does this model generate?
-This is a biomass accumulation curve
oIt shows the change in biomass over time
oIn this case at the end of 400 years the model has reached a steady state, where biomass is no longer increasing
oFinal biomass is g/m2, this means that the carbon storage for this forest at steady state is approximately gC/m2
And from this result you can ask a variety of questions to further student understanding of biomass, forest growth and carbon storage.
But what is going on if the same forest were only 50 years old?
ｧHow much carbon is it storing?
ｧIs it source or sink for atmospheric C?
oHow would carbon storage change if this forest were cut for firewood or turned into a ball field?
-These are the kinds of questions we hope students will answer when using the models

13. 1 Box Forest Biomass Model
Here is the interface of our model that you will see when it is first opened.
The green arrow allows you to view a story about the science in the model as it builds the model one box and one arrow at a time.
The red arrow takes you to the run page where you can change your input values and watch the results of running the model.
Also notice the tabs down the side: map, model, equation

14. 1 Box Forest Biomass Model
WoodBiomass(t) = WoodBiomass(t - dt) + (WoodNPP - WoodLitter - Harvest) * dtINIT
WoodBiomass = 0
INFLOWS:
WoodNPP = *Foliar_Nitrogen
OUTFLOWS:
WoodLitter = WoodBiomass * WoodLoss
Harvest = IF (TIME = HarvYear) then (WoodBiomass * HarvIntens) ELSE (0)
BiomassIncrement = WoodNPP - WoodLitter
Foliar_Nitrogen = 2
HarvIntens = 0
HarvYear = 0
WoodLoss = .02
The equation tab shows the detailed equations that run the model.
The map and model pages show how all the fluxes and pools are connected.

15. iSee Systems http://www.iseesystems.com/
The model we are using is built is a program called STELLA which is produced by isee systems. The isee systems company also produces a free model player which is downloadable from their website. You have this player on the cd we handed out, but we will also go through the process of registering for the player so that you will receive any important software updates.
Go now to iseesystems.com
Scroll to the bottom of the page and click on the P.
You will arrive at the registration page.

16. iSee Systems – isee player
If you have not registered before use the lower spaces to fill in your name and such, your password will be assigned to you and sent to your for future reference.
Now you are ready to go.

17. iSee Player Tutorial
Step by step instructions for how to use the isee player
Meant for first time users and as a refresher
Uses the 1 box forest biomass model as the example
Currently available as a presentation or printable pdf
Since most of you have never used the isee player before we created a tutorial in ppt format that you can view to help you better understand the technical aspects of the program. The file is in your modeling folder on your cd.

18. Open the program: isee player OR Stella
To get started:
Open the program: isee player OR Stella
From the menu bar at the top of the page select File-->Open
In the open screen navigate to your CD (found under my computer.
Once in the CD:
Select the modeling folder
Select the Biomass Accumulation Folder
Select BiomassAccumulation2.4.STM
Read the story (more science) by clicking the green arrow
Run the model by clicking the red arrow
Check out the isee player tutorial.ppt for more info about running the model (also in the modeling folder on your CD)
Now you will have the opportunity to look at the model, read the story and try running the model under a variety of inputs. To get started use the directions here. After some exploration time we will reconvene and look at a specific activity using the model.

19. from the Stella Biomass Accumulation Model
Forest Carbon Stocks in NH – a comparison of the US Forest Service State-level Carbon report with estimates
from the Stella Biomass Accumulation Model
In this activity, we use data on the acreage of different forest types, and mean foliage %N, to run the Stella Biomass Accumulation Model, generating an estimate of forest carbon stocks in NH. We then compare our model estimates to the values reported by the USFS, which are based on extensive field sampling and allometry.

20. Data for forest resources by state in Excel:
Collected data are part of the Forest Inventory Analysis program run by the US Forest Service.
Data for forest resources by state in Excel:
Go to the link:
Excel Spreadsheet of regional and state totals
Also available on CD:
FIATablesForStateTotals.xls
The data we are using for this activity were collected as part of the Forest Inventory and Analysis program which as been a major effort of the USDA Forest Service since 1930.
Mission: to make and keep a current comprehensive inventory and analysis of the present and prospective conditions of and requirements for renewable resources in the forest and rangelands of the US.
This slide shows you how to access the excel file, but we have also included it on your cd.

21. This exercise will soon be part of the Earth Exploration Toolbook.
EET is a series of independent chapters, each addressing a particular tool and dataset.
Each chapter highlights a particular classroom-ready example demonstrating how to use the tool to analyze and explore the data.
Focused on Earth Science topics
Current chapters are most appropriate for grades 6-16.

22. Learning Goals
After completion of this activity students will be able to…
Describe how forest biomass generally changes over time
Understand how forest biomass relates to carbon storage
Run the STELLA Biomass Accumulation Model using the iSee Player
Assess similarities and differences between field measured data and model outcomes

23. Open Files: CarbonStockScenario_template.xls
FIATablesForStateTotals.xls
Biomass Accumulation2.4.STM

24. STEP 1: The FIA Carbon Data File
View: FIATablesForStateTotals.xls
Notice the tabs at the bottom
Data is broken down by region (7 total)
After each region there is a separate tab for each state in the region
Use the scrolling arrows to view all tabs
Select the New Hampshire (NH) tab for this exercise

25. STEP 2: Examine FIA Carbon Data
Area of Forested Land
Total C Stock
Biomass Fraction of Total C Stock
We are looking at the last year for which data is available 1997.
Notice that tree species are grouped into common forest types.
One Forest type grouping exists for all eastern and central regions and a second exists for rocky mountain and pacific regions.
For our calculations of total aboveground carbon stock in trees for NH we need to use three data tables.
The area of forested land by forest type, the total amount of carbon stored by each forest type, and the fraction carbon stored in trees compared to the total.
Biomass Fraction = 153.6/521.7 = 0.29

26. STEP 3: Using the Carbon Data
View: CarbonStockScenario_template.xls
Notice the tabs at the bottom
Templates for
Region 1: East and Central US
Region 2: Rocky Mountains and Pacific
A tab for NH is already filled in with FIA Carbon Data
Table 2
Table 3
Table 4
Now view your carbon stock scenario template.
You will see templates for the two forest type groupings I just described as well as a tab specific to NH.
Select the NH tab.
Here you will notice that the template has been filled in using data from tables 2,3,4. Tables 2 and 3 are data copied directly and table 4 uses the calculation function to find the biomass fraction.

27. 1. Multiply total C stock by the biomass fraction
STEP 4: Converting Total C Stock to the Aboveground Forest Biomass Component (The largest tree component & comparable to model results)
*Both are automatically calculated in the excel sheet
2. Multiply the biomass C stock by 87%. This is the proportion of tree biomass found aboveground (Bolte et al. 2004).
1. Multiply total C stock by the biomass fraction
Now we want to find the total carbon storage in aboveground biomass, so we go through two more calculations.
First we multiply the total C stock by the fraction of biomass.
Then we multiply by the percent of biomass that is found aboveground. We are concerned with only aboveground biomass here, because that is what our model is designed to calculate. Studies have shown that about 87% of biomass is found aboveground.

28. STEP 5: Foliar Nitrogen by Forest Type
Foliar nitrogen content for each forest type was determined by averaging the foliar N for each tree species in the group.
More information about the foliar N values that were used can be found in the foliar N tabs of this file.
For more information about where the foliar N values come from check out the foliar N worksheets in this file

29. STEP 6: Run the Biomass Accumulation Model Using Foliar N
OPEN MODEL
Enter foliar N, then click Run
Now we will begin running the model for each of the forest types. You will be using the foliar N value as the only input, leaving wood turnover at 2% and harvest at zero.
To make the exercise more meaning full have students think about the foliar N value, and make a prediction about which forest type will have the greatest biomass accumulation.
You may also want to discuss in more detail why you would expect certain forest types to have the given foliar N value.

30. STEP 7: Record Model Data into Scenario Template
Once you run the model for a given foliar N, be sure to record the wood carbon value for each year in your template table. To make the exercise move along, you may have students split into groups and only do a few model runs each.
Use the model graph or table to find carbon storage by year (50, 80, 100, 150, 250)

31. STEP 8: Convert gC/m2 to million metric tons of carbon (MMTC)
*The model automatically calculates this so FIA State Carbon Values can be compared to model output values
Acres * 4046m2/acre * gC/m2 *kgC/1000gC * MTC/1000kgC * MMTC/1x106 MTC = MMTC
From column C (initially table 2)
You will notice that once you type in the wood carbon values in g C/m2 the boxes to the right are automatically filled in. The equations in these boxes convert g C/m2 to MMTC per all the acres of NH forest in a given forest type.

32. STEP 9: Compare FIA C storage to model C storage
Notice the FIA measured carbon storage lies within the range of carbon storage values produced by the model.
Based on the FIA carbon data and biomass model output we could estimate that in 1997(the FIA data collection year) New Hampshire forests were approximately 140 years old.

33. STEP 10: Data Analysis - Some Potential Questions
What do the data mean?
Are forests in New Hampshire really 140 years old?
What are some potential reasons for disagreement between measured and modeled data?
How does the model help us better understand forest carbon storage?
What is the future of carbon storage in New Hampshire forests? (How long will forests continue to increase their carbon storage?)
It is important to discuss with students what the data mean.
Keep in mind that measured and modeled data will not always match:
MODEL: perhaps the averaged foliar N used in the model is lower or higher than reality, perhaps the estimated wood turnover of 2% is incorrect
DATA: perhaps there were environmental conditions that affected growth and were not accounted for in the model