Growth predictions for tree species planted on marginal soybean lands in the Loher Mississippi Valley

ABSTRACT:

The establishment of bottomland hardwood forest stand and riparian buffers on frequently-flooded soybean (Glycine max.) land in the Lower Mississippi Valley represents a tremendous opportunity to provide both economic and environmental benefits to the region. Selecting appropriate sites for reestablishing tree cover, accurately predicting the productivity of planted trees and optimally matching species to site are critical for the economic justification and implementation of tree planting in conservation programs.

This study tests a low-cost methodology that incorporates the expert system developed by Baker and Broadfoot (1979) to predict tree growth rates calibrated with soils data from recently published Natural Resources Conservation Service (NRCS) soil surveys specific for combinations of tree species and soil series. This information is used to make site index projections for economically-marginal soybean land. Site index estimates ranged from 28.0 m (92 ft) for cottonwood (base age 30) on Mhoon soils to 18.0 m (61 ft) for sycamore (base age 50) on Forestdale soils. Use of this method results in tree growth predictions that are both more mechanistically-based and often more conservative than the site index projections published in soil surveys, particularly for species intolerant of flooding during the growing season.