PARENT SESSION
Poster Session #5: Disturbance Ecology I.
Monday, August 5. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Post-hurricane sprouting on undamaged tree stems.

Van Bloem, Skip^*,1, Murphy, Peter¹, Lugo, Ariel², ¹ Michigan State University, East Lansing, MI² International Institute of Tropical Forestry, Rio Piedras, PR

ABSTRACT- Sprouting is common to trees that have been wounded or broken following a disturbance. Less common is sprout development in trees that are undamaged after a disturbance. Following Hurricane Georges in 1998, we measured sprout development on over 1300 stems in Puerto Rican dry forest. We counted the number of sprouts, measured their location on stems, and followed survival for two years. About 30% of stems which showed no signs of wounding sprouted after the hurricane, with 3-6 times as many sprouts as on the 3% of stems that had sprouts before the hurricane. As expected, sprouting was also high on wounded stems. Over 75% of the hurricane induced stem sprouts originated from buds within 40 cm of the ground and over 87% were still living 2 years later. We hypothesize that the hurricane caused prolonged vertical displacement of the stems, resulting in production of ethylene near their bases. Ethylene production has been shown to inhibit auxin transport in stems, which could spur sprout development. The amount of sprouting in the forest and the location of the sprouts on stems would help explain why mature dry forests in the Caribbean are shorter, more slender, and have more multi-stemmed trees than do dry forests in other locations.

KEY WORDS: dry forest, sprouting, ethylene, wind stress