the number of bitter panicum transplants can be increased by segmenting large primary 

 culms. Survival potential is not reduced, and the segmented culms are more easily handled 

 than entire ones. 

 4. Planting Procedures. 



a. Selecting the Appropriate Procedures. Foredunes were established in two general 

 locations: (a) broad overwash areas (4 to 6 feet MSL), where foredunes have been eroded by 

 hurricanes or destroyed by blowouts; and (b) across hurricane washover channels, of lower 

 elevation behind the berm and more susceptible to surges. Two general techniques of 

 foredune construction were tested: (a) planting directly on the open beach at the original 

 elevation; and (b) constructing barren foredunes with sand fencing, and planting after the 

 dune line formed. Additionally, the same techniques were applied to stabilize a 

 wind-eroding (blowout) natural foredune, and to stabilize several extensive barren areas 

 behind the foredunes (oil well drilling pad; and an active dune field encroaching upon a 

 road). 



h. Planting on Level Sites. The least costly, easiest, and generally most successful 

 method of establishing a vegetated dune was by transplanting directly onto the level 

 backshore, in areas where the original dune was eroded by broad overwash or denuded and 

 then wind-eroded. No special preparations were required since subsurface moisture was 

 usually high enough for survival and wind erosion of the planting surface did not normally 

 occur. The plantings approximated the original location of the dune line, and were between 

 350 and 500 feet inland from the shoreline. 



All the north Padre plots and several in the south were established on this type of site. 

 Photo sequences of three major beach plantings are shown in Figure 31 (1,200-foot sea oats 

 dune, north Padre); Figure 32 (1,000-foot bitter pancium dune, north Padre); and Figure 33 

 (south 400-foot sea oats dune on south Padre). 



c. Planting Across Overwash Channels. In hurricane overwash channels, periodic storm 

 surges leave soils with salinity levels more toxic to transplants than on nonchanneled barren 

 backshore areas of higher elevation. From 1969 to 1971, plantings made in several south 

 Padre passes were unsuccessful. 



To close the passes with vegetated dunes, soil salinity must be lowered to allow 

 transplant survival by elevating the planting surface high enough to prevent frequent 

 saltwater inundation. Parallel 2-foot-high sand fences placed 8 to 12 feet apart at a width of 

 50 feet will create a flat-topped, broad, low dune relatively free of salt. Fences across two 

 south Padre passes were filled with sand and ready for planting within a year after erection. 

 Subsurface soil salinity of an unaltered washover pass during winter 1971-72 averaged 2,800 

 micromhos per centimeter, while during the same period, the elevated 2-foot dune averaged 

 only 500 micromhos per centimeter. Parallel 2-foot sand fencing was used with excellent 

 success to establish young dunes (1.5 years after planting) across two overwash channels 

 where normal planting methods resulted in total failure. A photo sequence of a 2-foot fence 

 planting is shown in Figure 34. On these dunes, mulching is not required, but irrigation may 

 be necessary during drought. 



114 



