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Forests and Changing Climate. “Mitigation deals mostly with carbon, adaptation deals with water” John Hoklren , OSTP “ Of all the outputs of forests, water may be the most important” National Academy of Sciences 2008. Expected Climate Change Effects.
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Forests and Changing Climate • “Mitigation deals mostly with carbon, adaptation deals with water” • John Hoklren, OSTP • “Of all the outputs of forests, water may be the most important” • National Academy of Sciences 2008
Expected Climate Change Effects • Precipitation: more rain & less snow • 33% snowpack loss • 1.6 °C increase by 2060 (Knowles 2002) • Earlier snowmelt • Faster snowmelt
Predicted Loss of Snowpack(Knowles 2002) *Effect greater in northern Sierra and Cascades 3 °C increase by 2070-2099 (Bureau of Reclamation 2011)
Modeled Mean Annual Flow& Percent Decrease (Null et al. 2010)
Kings River Experimental Watersheds KREW Pacific Southwest Research Station, Fresno, CA
Bull 203 Size: 342 acres Elevation: 7170-8170 ft Mean Temp: 6.9°C Providence 303 Size: 327 acres Elevation: 5670-6530 ft Mean Temp: 8.8°C
Findings: Water Yield & Climate • Precipitation amount (30-80 in/year) • Reaches maximum at 3,940 ft • Runoff ratio (discharge / precipitation) • 10% increase per 1,000 ft • Snow-dominated 2 to 3 times discharge • Trees at rain-snow using more water in winter (evapotranspirtation30 in)
Upper Kings River BasinGoulden et al. 2012 • Measured evapotranspiration • 10,000ft 18 in/yr • 6,600 ft 30 in/yr (60% higher) • Due to winter dormancy at cold, snow dominated • Both are mixed-conifer forest • Atmospheric lapse is -5.3 °C per 3,300 ft • 3 °C warming shift vegetation upslope • ET increase of up to 60%
Erosion: Roads & Wildfire • Increased sediment yield because • Climate change = vegetation disturbance • Road maintenance and decommissioning effective but will not mitigate increase in sediment from increased wildfire • Goode et al. (2012) Idaho case study
Findings: Flow Pathways • Determined using water chemistry • Primary: Subsurface flow ~ 60% • Soil-bedrock interface • Snowmelt runoff < 40% • Fall storm runoff < 7%
Adaptation: Multiple Stressors • Air pollution • Increased wildfire • Insect outbreaks • Climate change • “I would feel more optimistic about a bright future for man if he spent less time proving that he can outwit Nature and more time tasting her sweetness and respecting her seniority.” E.B. White