BALDCYPRESS (TAXODIUM-DISTICHUM (L) RICH) RESTORATION IN SOUTHEAST LOUISIANA - THE RELATIVE EFFECTS OF HERBIVORY, FLOODING, COMPETITION, AND MACRONUTRIENTS

In the early 1900s, old-growth baldcypress (Taxodium distichum) was co mpletely logged out of what is now the Manchac Wildlife Management Are a, located in the Lake Pontchartrain Basin, Louisiana. Natural regener ation of swamp did not occur; the area is currently dominated by bullt ongue (Sagittaria lancifolia) marsh. This study was conducted to isola te the major factors prohibiting cypress restoration. Specifically, fo ur hundred baldcypress seedlings were planted in a three-way factorial treatment arrangement that included nutrient augmentation (fertilized vs. unfertilized), management of entangling vegetation (managed vs. u nmanaged), herbivore protection (Tuber tree shelters, PVC sleeves, Tan glefoot), and elevation (included as a covariable). Highly significant differences in diameter growth were found for ah main effects. For th e herbivore protection treatment, relatively inexpensive PVC sleeves w ere as effective as Tuber Tree Shelters; unprotected trees experienced 100% mortality. Seedlings that received Osmocote 18-6-12 fertilizer s howed nearly a two-fold increase in diameter growth. Similarly, seedli ngs that were managed grew nearly two times greater in diameter than u nmanaged seedlings. However, seedlings that were: unmanaged grew nearl y two times greater in height than managed seedlings. This study indic ates that biotic factors are primarily responsible for the lack of cyp ress regeneration in southeastern Louisiana, not the prevalent, but la rgely untested, hypothesis of salt-water intrusion. Moreover, it is li kely that, with a combination of management techniques, it is possible to restore swamp habitat in this area. Though labor intensive in the short run (i.e., first few years), once established, these trees may s urvive for hundreds of years.