Soil, hydroperiod and bedding effects on restoring bottomland hardwoods on flood-prone agricultural lands in North Louisiana, USA

Abstract

Many of the bottomland hardwood forests of the Lower Mississippi Alluvial Valley, USA have been converted to agriculture, thus constituting a sizable loss in ecological and socio-economic functions. Bottomland hardwood forest afforestation on marginal agricultural lands has grown considerably since 1990. However, many failures in bottomland hardwood afforestation have occurred for various reasons, including misunderstandings or ignoring the relationships between species, soil and hydrology. In October 1996, a 32-ha tract on an abandoned agricultural field in Catahoula Parish, Louisiana, USA was site prepared for afforestation by bedding (moulding soil in parallel ridges). The following January it was planted with seedlings of Nuttall oak (Quercus nuttallii Palmer) and green ash (Fraxinus pennsylvanica Marsh.), and direct seeded with Nuttall oak. The objective of this study was to evaluate the effects of bedding (within three soil types) on species survival and growth. Soil redox potential measurements indicated that the soils were intensely anaerobic during frequent prolonged seasonal inundation and saturation events. Bedding clayey soils significantly increased mean height of planted and direct-seeded Nuttall oak, but not that for green ash. Bedding appears to be somewhat effective in restoring site microtopography, reducing soil hydroperiod and enhancing planted Nuttall oak height growth on poorly drained, clayey soils.