Researchers' Working Meeting on Climate Change Impacts
in the Mid-Atlantic Region
Penn State--June 8-9, 1998

(Summary by Jason Allard)

Panel:

Chair - David De Walle, Penn State
Richard Birdsey, USDA Forest Service
William Easterling, Penn State
Tom Smith, University of Virginia
Michael Slimak, US EPA National Center for Environmental Assessment
John Skelly, Penn State

For purposes of this researchers’ meeting, two types of land use were combined for a single panel. The MARA report will have separate sections on forestry and agriculture, however. David De Walle described deliberation by the forestry working group on two topics: (1) identifying the impacts of climate change on temperate forests, and (2) the focus of the working group.

(1)  Potential Impacts of Climate Change on Temperate Forests:

• Migration of temperate forests northward as warming occurs, replacing boreal forests.
  
• Provided there is adequate moisture, there may be an extension of the growing season associated with potential warming and CO₂ fertilization. This could result in increased productivity. However, increased photosynthesis may be balanced by increased respiration, so that net productivity would not change.
  
• Increased activity of insects and diseases with warming. Stressed forests will be more susceptible to insects and diseases.
  
• Increased incidence of fire and drought with warming, unless there is adequate moisture. This could offset the increased productivity due to an increase in CO₂ or warming.
  
• Increased nutrient cycling and nitrogen mineralization. The speed of nutrient and nitrogen replacement needs more study.

(2)  Focus of the Working Group

• Economic consequences of forest change on forest-based recreation (e.g., recreational patterns could be altered).
  
• Economic consequences of forest change on forest health and productivity. As a result of climate change, rates of growth may change and species competition may change.
  
• Impact of forest changes on landscape patterns and biodiversity (i.e., need to relate landscape changes to biodiversity changes).

Methods to study these topics need to be clarified, although ideas are forming about what databases to use.

Forest Service employees are actively involved in global change research, including:

• Developing databases for validating large-scale models.
  
• Providing forest inventory data. The data obtained from periodically measuring forest inventory plots can be used to characterize forests (e.g., location of forest type/species, amount of harvesting, forest growth rate, biomass estimates that help with carbon budgets, etc.).
  
• Examining biome redistribution under climate change.
  
• Examining how individual species are affected by climate change (e.g., black cherry is sensitive to climate change).
  
• Conducting other specific projects (e.g., silviculture and wildlife impacts, multiple stress studies, global carbon cycles studies, etc.).

Much of their data is available on the World Wide Web, and can be applied for regional analyses.

Understanding how climate change will affect agriculture in the Mid-Atlantic Region and its interaction with other sectors raises several issues:

• A comprehensive baseline of what agriculture is like today needs to include data on acres of harvested cropland, percent of land that is harvested, and the value of agricultural production (e.g., animals are more valuable than crops in the mid-Atlantic region). Furthermore, production and consumption trends in agriculture need to be projected into the future so that researchers have a better idea of the agricultural trends with which climate change will be interacting in the future.
  
• Identifying regional "hot-spots" (e.g., Chesapeake Bay, hog facilities in North Carolina).
  
• Regional Vulnerability: Places (and their people) need to be identified that will be more sensitive to climate change (e.g., currently important agricultural areas in the Chesapeake Bay area will be under water with a 1 meter rise in sea level).

Research Questions for MAR agriculture:

• "Means vs. Extremes": It is important to discuss increases in variability that may accompany climate change, not just changes in the mean conditions.
  
• "Scales that matter": Vast differences in the agriculture of the mid-Atlantic region occur within the grid cell of a GCM. Consequently, this scale may not be fine enough for MARA.
  
• "Adaptation possibilities": Farmers will adapt to climate change, but what are the adaptation possibilities?
  
• "How climate may change the interaction of pests and production": For example, as carbon dioxide concentrations increase, Little Bluestem will be competitively disadvantaged with regard to Honey Mesquite.

Tom Smith's discussion focused on VEMAP issues that are relevant to MARA:

• VEMAP used two groups of models for its 2 x CO₂ experiments: biogeographical (DOLY, BIOME2, MAPSS) and biochemical (TEM, BIOME-BCG, CENTURY). Using two groups of models results in a wide range of predictions, so that the assessment will not depend on the finding of just one model.
  
• Phase 2 of VEMAP has switched from using an equilibrium model to using a transient model.
  
• There are three basic models which look at forest responses to climate change:

• Canopy flux (ecosystem) - defines vegetation cover.
• Biogeography - examines the correlation of vegetation with climate or other environmental factors.
• Demographic - looks at individual plant's life cycle (birth, growth, death), competition with other plants, etc. He is working on linking demographic models with biogeography models.

EPA is working on a number of topics that might be relevant to MARA:

• Interconnection of rivers and streams.
• Indicators and signal detection.
• Biome redistribution, including both the rate of redistribution and public concern over the redistribution of specific species.
• Secondary impacts, such as increased use of pesticides due to more pests (as a result of warming).
• Ecological services; e.g., the impact that global warming may have on biogeochemical cycling, or the impact that global warming may have on pollinators (e.g., honeybees).
• How climate affects the way we use land.
• The need to ensure that global change research can be interpreted by the lay public.

Caution needs to be used in identifying causes of death in forests. A lot of natural factors cause forest death (e.g., gypsy moths, chestnut blight, tornadoes, ice storms, etc.) that are mistakenly attributed to humans.

Topics to be considered in the Mid-Atlantic Regional Assessment:

• Altered forest species responses to a changing environment.
• Altered species responses to "Liebeg's Law of the Minimum Factor".
• Altered species responses to ambient pollutant loading under increasing carbon dioxide and/or temperatures.
• Changing patterns of forest management practices.