Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Effects of Miconia on Hydrology (A version of this was presented by Thomas W. Giambelluca at the 2009 International Miconia Conference May 4-7 2009 Keanae, Maui, Hawai‘i) Hydrology: The branch of science concerned with the properties of the earth's water, especially its movement in relation to land. Miconia Calvescens: a slender, fast-growing tree from South America Alien Trees in Hawaiian Forests Biologists observed that alien trees damage rather than support hydrological functions, especially ground-water recharge. But until recently, no one had demonstrated exactly how alien trees affect the water cycle. Scientists from the University of Hawai‘i at Mānoa, University of South Carolina, and National University of Singapore sought to measure the hydrological effects of miconia. How might invasive trees affect the water cycle? What are their possible hydrological impacts? • large leaves shade out understory plants that act as a natural sponge • large leaves cycle high percentage of rainfall out of system through transpiration • shallow roots create conditions for hard, packed soil • all of the above increases likelihood of soil erosion •Miconia Pilot Study in Hawai‘i • Abundance of light under canopy • Ground cover • Throughfall drop size and velocity • Root exposure as a measure of soil loss Light abundance Ground Cover Thurston: Native Forest Onomea: Miconia Stand Throughfall: Rainwater that hits trees or other obstructions on its way to the earth Results of Drop Size Survey Natural Rain Miconia median drop size = 3.8 mm Very high compared with previous observations Artificial Spray Median drop size Miconia: 5.5 mm ‘ohia: 3.7 mm Miconia Covered Area vs. an Open Area: • Decreased number of raindrops impacting the soil surface • Significant increases in drop size (mass), and therefore significant increases in kinetic energy (KE) and momentum Result: more erosive rainfall that has a greater effective KE to erode and transport sediment, organics and nutrients Root exposure: an obvious sign of soil erosion.