Premise

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Premise
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• Three Basic Forms of Uncertainty
• - Level of Change
• - Process Impacts
• - Time and Space

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Premise
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• Three Basic Forms of Uncertainty
• - Level of Change
• - Process Impacts
• - Time and Space

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Simulated Temperature over the US
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Source Climate Change Impacts on the US, NAST,
2000
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Premise
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• Three Basic Forms of Uncertainty
• - Level of Change
• - Process Impacts
• - Time and Space

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Scale Uncertainty
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Biome Competition
Region
Landscape
Forest Competition
Biome Selection
Landscape Dynamics
Forest Selection
Species Competition
ha
Tree
Species Selection
Insect
1/10 ha
Disease
Week Month Year
Decade Century
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Global Change Certainty across Southeastern
United States Ecosystems Impacts and
Implications
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• Steven McNulty
• Research Ecologist
• USDA Forest Service
• Raleigh, NC

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Global change impacts range from the certain to
the unknown
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Certain change
Increased atmospheric CO2
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Very Likely Impacts In Southeastern
Forests (independent of climate change)
Increased Population
Increased Fuel loads
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This will lead to
Further forest fragmentation
Further restrictions in forest management options
Increase Fire Severity and Frequency
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Likely Impacts In Southeastern Forests (with and
without climate change)
Inter-annual precipitation variability
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Percent of the continental USA with a much above
normal proportion of total annual precipitation
from 1-day extreme events (more than 2 inches or
50.8mm)
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BW 7
Karl et al. 1996
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119
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232
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Uwharrie National Forest Current Soil Erosion Map
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Areas of Soil Erosion By 2030 On UNF
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American beech
Iverson et. al GTR NE265
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Sugar maple
Iverson et. al GTR NE265
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Likely Impacts In Southeastern Forests (with and
without climate change)
Inter-annual precipitation variability
Extended growing season and warming
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Timberland Acreage Shift 1993 2040 No Climate
Change Baseline
gt 25 DECLINE 5-25 DECLINE lt5
CHANGE 5-25 INCREASE
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Timberland Acreage Shifts by 2040 Due to Hadley
Climate Change
5-25 DECLINE lt5 CHANGE 5-25
INCREASE
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Unlikely Impacts In Southeastern
Forests (dependent of climate change)
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Loblolly pine
Iverson et. al GTR NE265
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Sweetgum
Iverson et. al GTR NE265
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Unknown Impacts In Southeastern
Forests (dependent of climate change)
Increasing CO2 on forest growth
Insect and disease impacts
Integrated stress impacts
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How a different critical nitrogen load could be
determined within the same ecosystem
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Conclusions
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• There is sufficient certainty regarding several
  areas of global change for assessing probable
  ecosystem impacts across the southern US during
  the next 50 years
• Other less certain impacts need to be prioritized
  for future research study based on cost and
  potential impact
• Synergistic impacts will be very difficult, if
  not impossible to predict

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Conclusions (cont.)
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• Thresholds and positive feedback impacts are
  poorly understood and could have the greatest
  potential for catastrophic change
• More emphasis should be placed on coping and
  mitigating those impact which have a high
  probability of occurrence while time and funding
  exist to address these issues