Abstract of Dissertation Presented to the
of the
Requirements for the Degree of Doctor of Philosophy
ECONOMIC AND
ENVIRONMENTAL ANALYSIS OF TREE CROPS ON MARGINAL LANDS IN
By
Matthew Langholtz
December 2005
Chair: Donald L. Rockwood
Major Department:
Tree crops can be used to remove contaminants from
reclaimed wastewater, restore ecological functions of phosphate and titanium mined
lands and to provide renewable energy in
Profitability measured as land expectation value (LEV) of 128 scenarios of Eucalyptus grandis cropping irrigated with reclaimed wastewater ranged from -$2,343 to +$2,762 ha-1 and was greatly reduced by high interest rates, high irrigation costs, and low yields. Each $1 kg-1 N increment in a dendroremediation incentive increases profit by $223-$376 ha-1, depending on interest rate and site productivity. Optimum management requires harvests every 2.6 to 4.0 years and replanting after two or three harvests, though the optimum number of stages per cycle would increase with improved coppice growth.
LEVs of Eucalyptus amplifolia
cropping on phosphate-mined lands in central
Average LEVs of slash pine (Pinus elliottii) stands established on titanium mined lands varied widely with
productivity, but on average were profitable and similar to those of unmined
lands. Optimum management is comparable
to that of conventional slash pine culture in northeast