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Evaluation of Alternatives for Restoration of Soil and Vegetation on Phosphate Clay Settling Ponds


This study, funded for one year but spread out over three years, examined the longer range success of extensive plantings of seedlings six years previously. The research identified species with high rates of survival and growth that accelerate successional restoration of forested wetlands. New experiments and the continued study of some of the 13,000 seedlings we planted earlier showed 70% survival and rapid growth of wetland trees that were planted at the appropriate time in succession and in place with hydroperiod normal to the successional sequence in Florida.

The severe limitations in natural importation of seeds which were previously shown to exist in post-mining landscapes of Florida were overcome by the plantings, even in dry years. Greenhouse experiments tested effects of soil age, fertilization, and seedling height on growth rates of wetland seedlings. Bald and pond cypress were compared.

A new technique, measuring near infrared solar energy absorption, showed wide differences among the vegetation types and stages of succession, thus allowing quantitative inferences about the transpiration and water budgets for present and future mining landscapes. Along with our three previous reports on managing ecosystem succession for reclamation purposes (1983, 1986, 1988), guidelines are given for controlling vegetation type so as to control water budget. Some vegetation such as pond cypress, conserves water by reflecting the sun’s infra-red insolation and reducing transpiration, whereas bottom land hardwoods absorb more infra-red insolation and transpire more.