Air Quality Portal for Forest Planning:
Critical Loads Component
September 26, 2012
Workshop
Claire O’Dea (USFS) and Cindy Huber (NADP)
Logistics
2
3
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1. Handouts can be downloaded using the “threedocument” icon in the upper right corner of your
Live Meeting screen
2. For technical difficulties, select the “Attendees”
button from the top of your Live Meeting screen
and double click on Cindy Huber’s name. Send
her a chat describing your difficulties.
3. Select the “Q&A” button from the top of your Live
Meeting screen to open the Q&A dialog box…
1
2
1. Type in your question and press enter, OR
2. Click the hand in the upper right corner of the Q&A dialog box to
virtually raise your hand and we will call on you during discussion
3. If the full slide is not showing up on your screen (you have to scroll
up/down or side/side), use the “Full-Screen Mode” icon in the lower
right part of the Live Meeting screen; [ESC] takes you out of mode
3
Ann Acheson and Rich Pouyat
Critical Loads Data Flow
12 Federal Agencies,
68 Educational Institutions,
45 State Agencies,
9 Native American Tribes
National Atmospheric
Deposition Program (NADP)
9 Industries,
10 Other Research Groups,
4 International Groups
Critical Loads of Atmospheric
Deposition Science Committee (CLAD)
EPA
Focal Center Utility Study (FOCUS)
NPS
FS Research and
Air Program
United Nations Economic Commission
for Europe – Coordinating Center on
Effects (UNECE-CCE)
National Forest use for Forest Planning
For use in reporting & regulatory assessments
For use in land management planning
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
ROLL CALL
Review Pre-work Documents
• Framework for Forest Service Critical Load
Development to Support the Forest Planning
Process
• Critical Loads Implementation Strategy for
Forest Planning
• Products List: Air Quality Portal for Forest
Planning
Background Readings
Pardo, L.H. 2010. Approaches for Estimating Critical Loads of Nitrogen and Sulfur
Deposition for Forest Ecosystems on US Federal Lands. Northern Research Station
General Technical Report NRS-71.
http://www.nrs.fs.fed.us/pubs/gtr/gtr_nrs71.pdf
Pardo, L.H. et al. 2011 Effect of nitrogen deposition and empirical nitrogen critical
loads for ecoregions of the United States. Ecological Applications 21(8): 3049-3082.
http://www.nrs.fs.fed.us/pubs/jrnl/2011/nrs_2011_pardo_001.pdf
OR
Pardo, L.H, M.J. Robin-Abbott, C.T. Driscoll, editors. 2010. Assessment of Nitrogen
Deposition effects and Empirical Critical Loads of Nitrogen for Ecoregions of the United
States. Northern Forest Research Station General Technical Report NRS-80.
http://treesearch.fs.fed.us/pubs/38109
Air Quality Portal for Forest Planning
• Goal 1: The portal will eventually guide specialists
through the entire air assessment process for Forest
Plan Revision
– Developing the critical loads component of the portal is
Phase I
– Data and some documents available by Nov/Dec to
support early adopter Forests
– Training tools and remaining documents available next
spring
• Goal 2: This will be a “living portal”
– There will be a process in place to update/revise
information as refinements and improvements are made
– These improvements are only possible with your help
Forest Plan Revision Process
• Forests will rely on Air Program to perform air
assessment and draft specialist report for
Forest Plan Revision
• Air Specialists will rely on the “Air Quality
Portal for Forest Planning”
http://www.fs.fed.us/biology/air/index.html
• Questions from Air Specialists directed to
Deposition FARM Team
Questions?
• Workshop will become increasingly technical
• Opportunity to ask high-level questions about
project scope and vision
• Additional questions can be directed to:
Claire O’Dea: cbodea@fs.fed.us
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
What is a “Critical Load”?
Critical Loads
Critical load:
“The quantitative estimate of an
exposure to one or more pollutants
below which significant harmful
effects on specified sensitive elements
of the environment do not occur
according to present knowledge.”
(Nilsson and Grennfelt 1988)
Critical loads can be developed for any
pollutant.
Forest health
decline
Chronic
acidification
Episodic
acidification
Change in plant
communities
Changes in soil
chemistry
Load (kg/ha/yr)
Critical loads are defined for specific indicators and effects.
Effect to specific resource
critical load
no harmful effect
harmful effect
Load (kg/ha/yr)
Approaches to developing CLs
• Steady-state mass balance models
• Empirical data from:
1) Spatial and temporal gradients of deposition to assess
thresholds for ecosystem response, or
2) Experimental manipulations of deposition loading
and associated ecosystem effects
Data “sideboards”
• Use existing data, no new data collection
• Use published Critical Loads
• Utilize CLAD database developed by FOCUS
• Coordinate with partners
Available Critical Loads Data
• CLAD Critical Load Database includes:
– Surface Water CLs of Acidity
• SSWC model used to calculate CLs
• Provides CLs for points with water chemistry measurements
– Terrestrial CLs of Acidity (McNulty)
• SMB equation used to calculate CL
• Estimated for 1 km2 grid across forested lands in the lower 48 states
– Empirical CLs for Nitrogen
• From Pardo et al. for Fungi, Herbaceous Vegetation, Forests, Nitrate
Leaching
• Lichen CLs developed by Linda Geiser
• Mapped at 4 km2 grid
– Site and Environmental Information
National Critical Load Database
Site and Environmental
Information
Values = 619,905
Modeled Critical Loads
Surface Water Acidification
Soil Acidification
Nutrient N
CLs = 254,581
Empirical Critical Load for
Nitrogen
CLs = 365,054
• Steady-States CLs for N+S
• 9,500+ Locations
• Multiple Approaches (SSWC,
MAGIC, FAB)
• Steady-States CLs for N+S
• 9,500+ Locations
• Multiple Approaches (SSWC,
MAGIC, FAB)
•Steady–state CLs for N+S
•Multiple Approaches
•SMB (McNulty et al. 2007)
•SMB(Pardo, Personal Communication)
• Linda Pardo et al. 2011 - Fungi, Lichens, Herbaceous, Forests
• Linda Geiser et al. 2010 - Lichens
Available Deposition Data
• Community Multi-Scale Atmospheric Model (CMAQ)
provides wet, dry, and total S and N deposition estimates.
– CMAQ 2002 (EPA recommends using this deposition)
•
•
•
•
Provides gridded estimates (36 km2 west, 12 km2 east)
Bias corrected
Precipitation corrected (using PRISM)
For CA only: Fenn re-sampled to 4 km2
– CMAQ 2006
• Provides gridded estimates (12 km2)
• Not bias corrected
• NADP
– Wet deposition only
– Gridded extrapolation using PRISM precipitation
Deposition Data (Expected improvements)
• NADP Total Deposition Science Committee
– Preparing a new total deposition product which FS can use
in future, will preview at upcoming NADP meeting
• New CMAQ (2006) deposition estimates
– Expected in January/February
– 12 km2 across nation
– Bias and PRISM corrected
Regional Data
• Where regional or local efforts have been made to
improve critical loads and deposition, use this
information.
• We will review what is available later in the
workshop.
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
Rationale behind the strategy
• Use best estimates available across landscapes to provide
information for all users.
• Allow for incorporation of regional and local information that
may have greater certainty in predictions.
• Realize that the reliability and certainty of CL and deposition
estimates is variable and take this into consideration in the
assessment process.
Critical Load Exceedance
• CLs Exceedance will be used to identify areas at
greatest risk of damage from air pollution.
• Exceedance = Deposition – Critical Load
+ value (Dep > CL) indicates harm is likely occurring, or
will occur in the future
- value (Dep < CL) indicates it is less likely harm is
occurring
Some CLs were
created for national or
regional scale “risk”
assessment. These
will be used to
determine:
• Whether there is likely to
be a CL exceedance, and
• Where additional data
should be collected to
verify/validate initial
predictions.
Some CLs were
developed with
extensive site specific
data.
• Nitrogen CLs and
exceedance based on
lichen communities in
Western OR and WA
• Can be used to develop
Target Loads.
DRAFT:
Forest Service Air Program
Critical Loads Implementation
Strategy for Forest Planning
Introduction
A critical load (CL) is the level of atmospheric deposition below which no detrimental ecological effects occur over
the long term, based on current scientific knowledge.
The Critical Loads section of the Air Quality Portal for Forest Planning hosts information for the following critical
loads data sets: 1) nationwide CLs of acidity for surface waters, 2) nationwide terrestrial CLs of acidity for
forested ecosystems, 3) nationwide empirical CLs of nutrient nitrogen for several ecosystem receptors and
responses (fungi, lichens, herbaceous vegetation, trees, nitrate leaching), and 4) a variety of regional CLs datasets.
Information for Alaska is not available for the terrestrial CLs of acidity for forested ecosystems. The critical loads
included in this strategy are thresholds for sulfur and nitrogen deposition. The Forest Service intends to eventually
incorporate critical levels for mercury and ozone deposition into this assessment process.
The portal also hosts information on atmospheric deposition. Nitrogen and sulfur deposition occur as wet
deposition (rain and snow), dry deposition (gases and particles), and occult deposition (cloud and fog). Deposition
information is measured and modeled from a variety of sources. The portal provides the 2002 Community Multiscale Air Quality (CMAQ) modeled deposition data layer to maintain nationwide consistency, and relies on this
data for CL exceedance calculations. We are working to obtain more accurate levels of nitrogen and sulfur
deposition at finer spatial resolution, and recommend the use of more current regional deposition data sets, if
available and appropriate for this purpose. All deposition datasets must reflect total deposition (wet and dry) for
both nitrogen and sulfur.
The CLs and deposition data are used together to determine areas of CL exceedance. Examining CL exceedance is
a “risk assessment” to evaluate the risk of sulfur and/or nitrogen deposition causing harm to the
resource/ecosystem of concern. Exceedance is calculated as: Exceedance = Deposition – Critical Load. If
deposition equals or exceeds the critical load, the pollutant is likely causing harm to the ecosystem, or will cause
harm in the future. If deposition is below the critical load, it is unlikely that harm is occurring. In other words,
deposition must be below the CL in order to protect the ecosystem. Exceedance calculations based on the 2002
CMAQ deposition data are provided on the portal for the three nationwide CL assessments described above.
The following strategy outlines the process, or steps, for incorporating the concept of critical load exceedance into
the air quality assessments for Forest Plan Revisions. Refer to the Air Quality Portal for Forest Planning for the
supporting documentation and details necessary to complete the assessment.
STEP 2: Define your concern.
The negative effects of atmospheric deposition occur on sites that are sensitive to acidification or
nitrogen saturation/eutrophication AND have excessive amounts of deposition. Decide whether to focus
on acidification or nitrogen saturation/eutrophication, or both, in the following analysis.
Include all CLs that showed exceedance in Step 1.
Consider the ecosystem characteristics that indicate sensitivity to deposition, as outlined in the following
two boxes. Interdisciplinary discussion with ecologists, geologists, hydrologists, soil scientists, fisheries
biologists, air specialists, etc. can help identify whether one, both, or neither of these CL categories
might be of concern to the Forest. Results of these discussions can reduce the list of CLs you address in
your analysis. (Later you will see how maps of CL exceedance can be used to identify areas at greater
risk of harm from deposition.)
If investigation indicates a focus on empirical CLs of nutrient nitrogen, review the “User’s Guide for
setting empirical critical loads for nutrient nitrogen” (available on the Portal) for an explanation of how
to refine the broad CL ranges provided for each Forest and incorporate the concept of data reliability.
Proceed to Step 3 to examine the extent and severity of critical load exceedances.
Does your Forest have any of the characteristics of ecosystem sensitivity?
Acidity
o
o
o
o
o
o
Is there elevated deposition of Sulfur or
Nitrogen in the area?
Does the lithology/geology of the area have a
low buffering capacity for acidity?
Does the area have shallow soils?
Does the area have very old weathered soils?
Is the area found at high elevation?
Do you have water chemistry data that
indicates low buffering capacity (i.e. ANC, pH
values)
Nutrient Nitrogen
o
o
o
o
Is there elevated deposition of Nitrogen in the
system?
Did the area historically have low Nitrogen
deposition?
Have there been observed shifts in species
composition of sensitive species in the area?
Are there elevated stream water nitrate
concentrations?
STEP 3: Use CL exceedance to conduct a closer examination of
atmospheric pollution impacts.
In this step you will examine CL exceedance patterns across the Forest to better understand the
extent and severity of potential impacts to resources, as well as the reliability of the CLs
exceedance information. CL exceedance maps for each of the nationwide CL efforts are hosted on
the portal. For each type of CL identified in Steps 1 and 2, examine the extent, severity, and
reliability of the exceedances. “Extent” refers to the percent of landscape in exceedance, while
“severity” refers to the amount/quantity of exceedance. For example, one Forest may exhibit
exceedance in only 1% of land area while another Forest exhibits exceedance in 75% of land area
(extent); and deposition in one Forest may be only slightly above the CL while deposition in
another Forest may exceed the CL by a large amount. Reliability is an expression of the certainty
of the CL and exceedance estimates. Understanding the extent, severity, and reliability of
exceedance on your Forest can help you interpret patterns and make appropriate management
recommendations. More information on these topics is available on the Portal.
Spatial representation of CL exceedance information is provided on the portal for the three
nationwide CLs efforts. The portal also hosts important Forest Service boundaries including
National Forest, Class I Area, Wilderness Area, 6th level HUC, and Land Type Association, so that
exceedance information can be examined by unit for management purposes. Special attention
should be given to National Forest and Class I boundaries. Before you investigate exceedance
metrics, check to see whether local critical load information or improved regional estimates of
deposition are available for your Forest. If you have access to more site-specific data, it is
recommended that you proceed to Steps 4 and 5 where you will select the appropriate CL and
deposition data before returning to this step to examine the extent, severity, and reliability of CL
exceedance. Detailed instructions on assessing these CL exceedance metrics, including steps for
geospatial analyses, are available on the portal. A tabular description of this analysis is shown
below.
TABLE ON SEPARATE SLIDE
Complete this analysis and proceed to Step 6 for guidance on interpreting exceedance information.
*The variable reliability rating for the empirical CLs of nutrient
nitrogen (non-lichens) will be important when interpreting
exceedance information and making management
recommendations in Step 6.
STEP 4: Review the critical loads available for the Forest.
The Critical Loads section of the Air Quality Portal for Forest Planning hosts the following
critical loads data sets: 1) nationwide CLs of acidity for surface waters, 2) nationwide CLs of
acidity for forested ecosystems, 3) nationwide empirical CLs of nutrient nitrogen for several
ecosystem receptors and responses, and 4) a variety of regional CLs datasets. Only published
critical loads are used in this process. An “Available CLs Background” document will identify
the types of critical loads that are available, by Region and/or Forest, with additional
information on how they were calculated and instructions on how to use them appropriately.
Most Forests will use the nationwide CLs because this is the best information available. Some
Forests will have access to refined CLs and/or deposition data; this data should be used when
available to reduce uncertainty inherent in nationwide efforts.
Important Concept: The degree of uncertainty associated with the different critical loads
calculations will vary with environmental variability (i.e., the high degree of variability in soils)
and the method of critical load calculation (i.e., the use of site-specific data versus
extrapolated/modeled data). Step 6 incorporates uncertainty into future recommendations.
Go to Step 5 where you will identify the best deposition data to use in your analysis.
STEP 5: Identify the appropriate deposition information to compare with critical loads.
There are different sources of deposition information that can be used in CLs assessment. To
understand the threat of negative effects of deposition to your Forest you must compare the CLs
from Step 4 with current levels of deposition. Deposition information is measured and modeled
from a variety of sources. Absent specific rationale to the contrary, we recommend using the
2002 CMAQ deposition data provided on the portal to maintain nationwide consistency. A table
showing the availability of deposition data by geographic area, providing the pros and cons of
each data source and describing appropriate uses is available on the portal.
After the appropriate deposition has been selected for each CL data set under review,
exceedance is calculated using the following equation: Exceedence = Deposition – Critical
Load. Additional guidance on exceedance calculation is available on the portal.
Proceed to Step 6 for guidance on interpreting exceedance information.
STEP 6: Interpret the CL exceedance information.
Interpretation of CL exceedance must consider the type of CL (empirical vs. modeled), the site specificity of
the data used in calculating the CL, and the quality of the deposition estimates. Management
recommendations will vary with the reliability or certainty of the CL exceedance estimates.
For example, the CLs of acidity for surface waters provided in the portal are based on water chemistry
measurements from specific sample sites and have a high level of reliability. Coupled with measured
deposition information, CL exceedances for surface water allow land managers to develop target loads.
Target loads represent a policy or management decision about the amount of deposition that is an acceptable
level of resource protection. On the other hand, the terrestrial CLs of acidity for forested ecosystems are
created from geospatially extrapolated information that is acceptable for understanding risk across the
landscape, but does not have the adequate site specificity necessary to make management recommendations.
Exceedance of the CLs of acidity for forested ecosystems should therefore only be used for creating a
monitoring plan to gather site specific data.
You should now have a list of CLs that represent Forest resources of concern, as well as information on the
relationship between deposition and the CL (the CL exceedance). Your exceedance information may have
changed as you refined your analyses (through investigation of exceedance metrics, empirical N CL guidance,
or the use of local/regional CLs and deposition information).
Review all CL exceedances applicable to the Forest:
•
If there is no CL exceedance on the Forest (Deposition < CL) there is very low risk that the area has any
detrimental effects from S and N.
o Action: Monitor NADP reports for deposition trends. If deposition is increasing, address possible
need for field measurements (e.g., water chemistry) in the next planning cycle. Review the
“Monitoring Strategy” and the “Next Steps” briefing paper in the Critical Loads section of the
Air Quality Portal.
•
If CL exceedance is occurring (Deposition > CL) there is a risk that the area is experiencing
detrimental effects from S and N. Implement instructions in the boxes below according to the type of CL
used and review the “Next Steps” briefing paper in the Critical Loads section of the Air Quality Portal.
•
If you conducted a refined analysis and found that deposition is within 10% of the CL and increasing in
recent years, consider implementing instructions in the boxes below according to the type of CL used
and reviewing the “Next Steps” briefing paper in the Critical Loads section of the Air Quality Portal.
STEP 6: Interpret the CL exceedance information. (CONTINUED)
Surface Water CLs AND
Reliable Empirical Nutrient N CLs
(including lichen results from Mediterranean
CA, PNW, Sierras)
AND Appropriate Regional CL Efforts
Nationwide surface water CLs and reliable empirical
nutrient N CLs (as determined in Step 2) have lower
associated uncertainty because they were calculated
with site-specific/locally relevant data. In addition,
you may have access to regional CL results based on
site-specific data.
Deposition > CL : CL is exceeded, ecosystem is
currently impacted, or likely to be in the future.
Action: IDENTIFY a TARGET LOAD to protect or
restore key components of the ecosystem per FS
Directives. Go to the “Target Load Strategy.”
Target Load Strategy
(under development)
Critical Loads of Acidity for Forested
Ecosystems
AND Other Empirical Nutrient N CLs
These CLs were developed to assess regional
differences in exceedance, not for land
management decision-making. They should be
used to guide further monitoring and/or research
experiments in areas of predicted exceedance.
Deposition > CL : CL exceedance is possible.
Action: Create stratified monitoring for sitespecific water chemistry, soil chemistry, and/or
lichens as appropriate to refine analysis and
confirm exceedance predictions. For other
empirical nutrient N CLs you may want to work
with FS research scientists to develop an N
experiment or gradient study that will improve
reliability of the CLs. Go to the “Monitoring
Strategy.”
Monitoring Strategy
(under development)
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
Introduction
A critical load (CL) is the level of atmospheric deposition below which no detrimental ecological effects occur
over the long term, based on current scientific knowledge.
[Description of critical loads and available critical loads information]
[Description of atmospheric deposition and available deposition information]
[Description of critical load exceedance and available exceedance information]
The following strategy outlines the process, or steps, for incorporating the concept of critical load exceedance
into the air quality assessments for Forest Plan Revisions. Refer to the Air Quality Portal for Forest Planning for
the supporting documentation and details necessary to complete the assessment.
Associated Portal Products:
• Planning Rule Directives
• Briefing papers
• Atmospheric deposition (N vs. S)
• Critical loads (empirical v. calculated)
• Critical loads strategy/flowchart
STEP 1: Initial critical load exceedance screening.
In this step, exceedance calculations will be used as a screening tool to identify the extent of CL analyses that
Forests will need to include in Forest Plans. The Critical Loads section of the Air Quality Portal for Forest Planning
hosts a “National Forest Exceedance Table” that documents critical load exceedances for each National Forest.
Locate your Forest in the table to see whether any of the CLs are exceeded, and follow the instructions:
•
•
NO CL exceedance: document this finding and no further assessment is required. Annual reports from NADP
should be monitored for deposition trends. If deposition is increasing, CL exceedance should be reevaluated
during the next Forest Plan revision.
One or more CLs exceeded: proceed to Step 2.
Associated Portal Products:
• National Forest Exceedance Table (and associated
development protocols)
Critical Load Exceedances
Surface
Water CL of
Acidity
Terrestrial CL
of Acidity
NF #1
Y/N
NF #2
Y/N
Empirical CL for nutrient nitrogen
Mycorrhizal
fungi
Lichens
Herbaceous
vegetation
Trees
Nitrate
Leaching
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
Y/N
STEP 2: Define your concern.
The negative effects of atmospheric deposition occur on sites that are sensitive to acidification or excess
nutrient nitrogen inputs AND have excessive amounts of deposition. Decide whether to focus on acidification or
excess nutrient nitrogen, or both, in the following analysis:
•
•
•
Further investigation should be performed on the type(s) of critical loads in exceedance, identified in Step 1.
Consider the ecosystem characteristics that indicate sensitivity to deposition. Interdisciplinary discussion
with geologists, hydrologists, soil scientists, fisheries biologists, and air specialists can help identify whether
one, both, or neither of these CL categories might be of concern to the Forest. Results of these discussions
can reduce the list of CLs you address in your analysis.
If investigation indicates a focus on empirical CLs of nutrient nitrogen, review the “Empirical CLs of Nutrient
Nitrogen GTR User’s Guide” for an explanation of how to refine the CL ranges provided for each Forest.
Associated Portal Products:
• Atmospheric deposition Briefing Paper (N vs. S)
• Empirical CL of nutrient nitrogen GTR User’s Guide
STEP 3: Use CL exceedance to conduct a closer examination of
atmospheric pollution impacts.
In this step you will examine CL exceedance patterns across the Forest to better understand the extent and
severity of potential impacts to resources. “Extent” refers to the percent of landscape in exceedance, while
“severity” refers to the amount/quantity of exceedance.
Spatial representation of CL exceedance information is provided on the portal for the three nationwide CLs
efforts. The portal also hosts important Forest Service boundaries including National Forest, Class I Area,
Wilderness Area, 6th level HUC, and Land Type Association, so that exceedance information can be examined by
unit for management purposes. If you have access to more site-specific data, it is recommended that you
proceed to Steps 4 and 5 where you will select the appropriate CL and deposition data before returning to this
step to examine the extent and severity of CL exceedance.
Associated Portal Products:
• GIS data layers
• Boundaries (NF, Class I, Wilderness, HUC12, LTA)
• Exceedance maps
• Aquatic CLs of acidity (point data)
• Terrestrial CLs of acidity for Forested Ecosystems (1km grid)
• Empirical CLs for nutrient N (lichens, mycorrhiza, herbaceous vegetation,
trees)
• Protocol for exceedance map examination (exceedance metrics)
STEP 4: Review the critical loads available for the Forest.
The Critical Loads section of the Air Quality Portal for Forest Planning hosts the following critical loads data sets:
1) nationwide CLs of acidity for surface waters, 2) nationwide CLs of acidity for forested ecosystems, 3)
nationwide CLs of nutrient nitrogen for several ecosystem receptors, and 4) a variety of regional CLs datasets.
Only published critical loads are used in this process. An “Available CLs Background” document will identify the
types of critical loads that are available, by Region and/or Forest, with additional information on how they were
calculated and instructions on how to use them appropriately.
Most Forests will use the nationwide CLs because this is the best information available. Some Forests will have
access to more site- specific data; this data should be used when available to reduce uncertainty inherent in
nationwide efforts.
Associated Portal Products:
• Available CLs Background (information on the types of critical loads available and
how they were calculated/instructions on how to use them appropriately)
• CL maps GIS data layers
• Aquatic CLs of acidity
• Terrestrial CLs of acidity for Forested Ecosystems (1km grid)
• Empirical CLs for nutrient N (lichens, mycorrhiza, herbaceous vegetation, trees)
• Regional data (if provided to WO)
STEP 5: Identify the appropriate deposition information to compare with critical loads.
There are different sources of deposition information that can be used in CLs assessment. To understand the
threat of negative effects of deposition to your Forest you must compare the CLs from Step 4 with current levels
of deposition. Deposition information is collected and modeled from a variety of sources. Absent specific
rationale to the contrary, we recommend using the 2006 CMAQ deposition data provided on the portal to
maintain nationwide consistency. A table showing the availability of deposition data by geographic area,
providing the pros and cons of each data source and describing appropriate uses is available on the portal.
After the appropriate deposition has been selected for each CL data set under review, exceedance is calculated
using the following equation: Exceedence = Deposition – Critical Load. Additional guidance on exceedance
calculation is available on the portal.
Associated Portal Products:
• Deposition maps GIS data layers
• 2002 CMAQ
• NADP site locations
• Regional data (if provided to WO)
• Instructions/protocol for calculating CL exceedance
STEP 6: Interpret the CL exceedance information.
Management recommendations will vary with the reliability or certainty of the CL exceedance estimates.
Review all CL exceedances applicable to the Forest:
• If there is no CL exceedance on the Forest (Deposition < CL) there is very low risk that the area has any
detrimental effects from S and N.
• Action: Monitor NADP reports for deposition trends. If deposition is increasing, address possible need
for field measurements (e.g., water chemistry) in the next planning cycle. Review the “Monitoring
Strategy” and the “Next Steps” briefing paper in the Air Quality Portal.
• If CL exceedance is occurring (Deposition > CL) there is a risk that the area is experiencing detrimental
effects from S and N. Implement instructions according to the type of CL used and review the “Next Steps”
briefing paper in the Air Quality Portal.
• If you conducted a refined analysis and found that deposition is within 10% of the CL and increasing in
recent years, consider implementing instructions according to the type of CL used and reviewing the “Next
Steps” briefing paper in the Air Quality Portal.
Associated Portal Products:
•
•
•
•
Target loads strategy
Monitoring strategy
Multiple CLs exceeded guidance
Briefing paper on next steps (improve data reliability through monitoring or
calculate TLs and determine management implications)
STEP 6: Interpret the CL exceedance information.
Interpretation of CL exceedance must consider the type of CL, the site specificity of the data used in calculating the
CL, and the quality of the deposition estimates. Management recommendations will vary with the reliability or
certainty of the CL exceedance estimates.
Possible Management Recommendations:
• No biomass removal in areas of high sensitivity to acidification (GWNF)
• Additional soils data and assessment in areas sensitive to acidification
(Monongahela NF)
• Liming to restore acidified streams (Jefferson NF)
• We need more site specific information where risk is high but data is
insufficient – what monitoring should be recommended in the Forest Plan?
(Monitoring strategy document)
Additional Supporting Materials:
•
•
•
•
•
References (include references for mercury and ozone)
Sample specialist report(s) on critical loads for forest planning
Air Specialists Contact list
FAQs (if appropriate)
Training materials
Portal Products Summary
• Questions or suggestions?
• Volunteers to create/review documents:
– Briefing papers
– Target loads strategy
– Sample specialist report for Forest Plan
– Training materials
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
Regional CL Data - East
• Southern Appalachians
• Surface Water CLs of Acidity extrapolated across landscape
(Hessburg et al.)
• Northeastern US
• Terrestrial CLs of Acidity for New England (NEG-ECP Forest
Mapping Working Group)
• Terrestrial CL of Acidity for New York (Miller)
• Aquatic CL of Acidity for NE and NY (Miller)
Regional CL Data - West
• California
• Empirical CLs of Nitrogen (vegetation) specific to California
(Fenn et al. 2008 and 2011, Jovan 2008, Rao et al. 2010)
• CLs of Nitrogen for lakes in Sierra Nevada (Baron et al. 2011)
• Western OR and WA
• Lichen community based CLs developed by Geiser et al.
• Mapped on a 2 km2 grid
• Rocky Mountains
• CLs of Nitrogen for lakes in Rocky Mountains (Baron et al. 2011)
• CLs of Nitrogen for alpine vegetation (Bowman et al. 2012)
Incorporating Regional
and Local Efforts
• Regional “round robin” to learn about
additional efforts
• Regions requested to provide additional
information for inclusion in the Portal in
tabular or GIS format
• Schedule discussions with Regions if needed
Workshop Agenda
12:00 – 12:30
Welcome and introduction
12:30 – 1:00
Overview of available data
1:00 – 1:45
Review CLs strategy flowchart
1:45 – 2:15
Break
2:15 – 3:00
Portal products discussion
3:00 – 3:30
Regional efforts discussion
3:30 – 4:00
Final Q&A
*Times listed are Eastern Daylight Time
“Living Portal” Concept
• Phased portal implementation
• Information (data/maps) will improve over
time with input from Regions and CLAD
• Continuous call for information, suggestions/
feedback, sample Forest Plan language
The portal will only be as good as the feedback
we receive! Please give us your feedback!
QUESTIONS?
SUGGESTIONS?
Additional questions can be directed to Claire O’Dea: cbodea@fs.fed.us