Swamp tree data used in Dixon (2002) and other papers, 734 tree
locations (630 live trees), 5
categories (4 species and other) goodplot1.txt
Columns are x,y coordinates, indicator for live (1) or dead
(0), and species code
(FX:Fraxinus spp.,ash, NS:Nyssa sylvatica,
black gum, NX: Nyssa aquatica, Water tupelo, OT: Other
species,
TD: Taxodium distichum, Bald cypress).