PROJECT DESCRIPTION: Studies of seedlings and saplings are and have been conducted on several landslides and plots on the LEF. The primary purposes are to study seedling recruitment and seedling and sapling growth and the effect of hurricane disturbance (specifically Hugo) on these processes as related to the degree of canopy disturbance, and the temporary reduction in shade from the defoliation of the canopy under distinct soil conditions.
9Ha Study
The primary purpose of this study is to look at seedling recruitment, and the growth of seedlings and saplings as it relates to the degree of canopy disturbance caused by Hurricane Hugo. Although all trees down to 1-cm dbh will eventually be identified and measured for the separate 16-ha grid project, the smallest trees will not be measured for at least a year, and seedling will not be included in the 16-ha grid program. The seedling/sapling plots in the 9-ha grid will allow us to follow early responses of seedlings and saplings to increased light. Tree maps for the 16-ha grid which will encompass the 9-ha grid) will eventually be used to determine the proximity of seed-source trees to each plot.
Treefall Pits Study
In this study, I compared seedling and sapling dynamics in soil pits and undisturbed forest floor, were both environment has experienced a temporary reduction in shade from the defoliation of the canopy during Hurricane Hugo (September 1989) but had soil conditions that were distinct. Soil pits were chosen as the microsite within the treefall gap most likely to differ in soil characteristics from the adjacent forest and most likely to alter plant establishment patterns. Soil mounds, important sites of establishment in some temperate forests (Webb 1999), erode quickly under the high rainfall conditions in Puerto Rico and were not considered in this study. I asked the following questions: (1) how does the soil physical environment differ between the soil pit and the forest floor?; (2) do tree species that have N-fixing symbionts influence soil nutrients or species composition of colonizers?, and (3) what are the consequences of uprooting and defoliation for populations of seedlings and saplings and for tree recruitment?
Created By: Eda C. Melendez-Colom (emelend@lternet.edu
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Last Modified On: April 25, 2002