Climate Change and Other Environmental Stress impacts on North American Forests and Rangelands Steven McNulty, USDA FS Presented to the North American Forestry Commission Integration Workshop March, 2008
Management Strategy for Coping with Increased Sea Level Rise Coastal forests will be inundated and coastal beach erosion will increase. Forest managers should work with land owners at a local scale to plant mangroves and other soil retention vegetation to delay terrestrial loss for a long as reasonably possible.
Management Strategy for Coping with Increased Wild Fire Manage for and encourage more fire tolerant grass and tree species Increase public education and preparedness regarding wild fire prevention and individual preparation and control Compared to climatic drivers, fuel reduction control measures will be largely ineffectual
Likely Impacts Inter-annual precipitation variability and soil erosion
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) Karl et al. 1996 BW 7
Management Strategy for Coping with Increased Soil Erosion Continue to encourage standard soil erosion control practices such as contour plowing, winter cropping, shelter belts, and buffer strips Relocate trails away from streams Use bridge mats and culverts at stream crossings
Likely Impacts Changes in Productivity and Economic Value
Timberland Acreage Shifts by 2040 Due to Hadley Climate Change 5%-25% DECLINE <5% CHANGE 5%-25% INCREASE
Management Strategy for Coping with Changing Rangeland and Forest Productivity Work with local land owners to examine alternative crops (e.g., shift from red pine to loblolly pine plantations or from corn to wheat) as climate shifts occur Examine options for changing management strategy for exists crops (e.g., wider tree planting, fewer head per acre)
How a different critical nitrogen load could be determined within the same ecosystem N dep = 10 kg/ha/yr N leaching = 0 Mortality = 0% Critical N > 10 kg Load N dep = 10 kg/ha/yr N leaching = 1 Mortality = 10% Critical = 10 kg Load + 3 yr Drought Stress N dep = 10 kg/ha/yr S dep = 10 kg/ha/yr N leaching = 15 Mortality = 75% Critical = 8 kg Load + 3 yr Drought Stress N dep = 10 kg/ha/yr N leaching = 25 Mortality = 100% Critical < 5 kg Load + 3 yr Drought Stress + fire S dep = 10 kg/ha/yr
Conclusions There is much we understand about climate change and the impacts it is having and will continue to have on North American rangelands and forests. There are also management strategies that can be used to minimize some of the negative impacts of climate change However, while we have great confidence in the direction of climate change, there remains uncertainly regarding the rate and ultimate level of climate change. Much of this uncertainty is due to the uncertainty of society to address future green house gas emissions.