Using long-term data from the New and Old World to understand the influence of typhoon/hurricane frequency on forest structure.
Hamburg, Steven*,1, Lin, Teng-chiu2, 1 Brown University, Providence, RI2 National Changhua University of Education, Changhua, Taiwan
ABSTRACT- Strong tropical storms are known to affect forest dynamics in both tropic and temperate regions. Yet, our understanding of cyclone (typhoon and hurricane) effects on forest dynamics disproportionally comes from studies of forests in the New World. New World hurricanes occur with frequencies an order of magnitude lower than typhoons in the Northwest Pacific and the land areas affected are only one third as large. In northwestern Taiwan an average of1.4 typhoons/y with hurricane level intensities impact the forest, while in New England and Puerto Rican forests experience an average of 0.02 and 0.07 hurricanes/y. The rates of hurricane disturbance in Puerto Rico have been referred to as frequent and rates of stream water chemistry recovery as rapid, yet by contrast in Taiwan the forest has an order of magnitude more frequent disturbances and more rapid recovery. Stream water concentrations of total P, NO3- and NH4+ increase dramatically during typhoon disturbance, but remain elevated for only a few days in Taiwan, in contrast to the years observed in Puerto Rico following Hurricane Hugo. In Puerto Rico secondary succession occurring in large gaps formed by hurricanes contributes to the retention of soil nutrients and recovery of stream water chemistry to pre-hurricane levels. Yet, in Taiwan large gaps are rare and most trees survive typhoon disturbance with at least some photosynthesizing leaves, thus they are capable of taking up nutrients continuously. Tropical cyclone effects on forest dynamics differ significantly between the New Word and at least some parts of the Old World suggesting that assumptions about the similarity of forest responses to cyclonic events are suspect.
Key words: hurricanes-typhoons, ilter, asia, watershed
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