IV. SUMMARY 



Barrier dunes which are usually formed by vegetation accumulating 

 windblown sand, serve as flexible barriers to storm tides and as sand 

 stockpiles, nourishing the beach during storm attack. When windblown 

 sand is available, they may be built by planted vegetation, sand fences, 

 or a combination of the two. 



Wood or fabric fences should have 40 to 50 percent porosity and be 

 60 centimeters to 1.2 meters high, with multiple fences spaced 4h apart. 



Planting in the barrier dune zone is primarily done with perennial 

 grasses. In the North and mid-Atlantic region, the first choice is 

 American beachgrass planted in fall, winter, or early spring. Plant one 

 to five stems per hill, 20 to 35 centimeters deep, in moist sand. Space 

 the plants 45 to 60 centimeters apart or in a graduated pattern, dense 

 in the center and thinning toward the edges. Apply 100 to 150 kilograms 

 of nitrogen and 30 to 50 kilograms of phosphate per hectare in two to 

 three applications, the first season. In the mid-Atlantic, add 10 to 25 

 percent bitter panicum to American beachgrass to form a mixture more 

 resistant to disease and insect damage. In the South Atlantic region, 

 plant American beachgrass with small amounts of bitter panicum or sea 

 oats on the coasts of the Carolinas, and bitter panicum with a small 

 amount of sea oats farther south. Plant American beachgrass in the 

 winter or spring. Plant one to five stems per hill, one stem per hill 

 with other grasses, 20 to 35 centimeters deep in moist sand. Space plants 

 45 to 60 centimeters apart or on a graduated pattern thick in the center, 

 thinning toward the edges. Apply 100 to 150 kilograms of nitrogen and 30 

 to 40 kilograms of phosphate per hectare divided into two to three appli- 

 cations the first year. In the gulf region, plant bitter panicum with a 

 small amount of sea oats in late winter, early spring, or during wet 

 periods in late spring and early summer. Set one stem per hill, 20 to 35 

 centimeters deep. Space plants 60 centimeters apart or in a graduated 

 pattern, thick in the center, sparser toward the edges. Apply 100 to 

 180 kilograms of nitrogen per hectare the first year in two to three 

 applications beginning in late April or May. In the North Pacific region, 

 set European beachgrass three to five stems per hill, 30 to 35 centimeters 

 deep. Space 45 centimeters apart or in a graduated planting pattern, 

 dense in the center, thinning toward the edges. Plant only when tempera- 

 ture is below 16° Celsius and when moist sand extends to within 8 centi- 

 meters of the surfaceo Apply 40 to 60 kilograms of nitrogen per hectare 

 in the first half of April in the first growing season. In the South 

 Pacific region European beachgrass should be planted three to five stems 

 per hill, 30 centimeters deep, 45 centimeters apart, or on a graduated 

 planting pattern, dense in the center, thinning toward the edges. Plant 

 only when temperature is below 16° Celsius and when moist sand is within 

 8 centimeters of the surface. Where emphasis is on stabilization, sea 

 fig may be used. Set the sea fig cuttings 10 to 15 centimeters long into 

 moist sand. Space 45 to 60 centimeters apart or broadcast cuttings during 

 cool, rainy periods. Apply 40 to 60 kilograms of nitrogen per hectare in 

 spring of first growing season to either beachgrass or sea fig. Adjust 



105 



