(1) The best way to maintain a fence-constructed dune is to plant 

 it with vegetation. 



6.44 DUNE CONSTRUCTION - VEGETATION 



Few plant species survive in the harsh beach environment. Those that 

 thrive along beaches are adapted to conditions that include abrasive and 

 accumulating sand, exposure to full sunlight, high surface temperatures, 

 occasional inundation by salt water, and drought. The plants that do sur- 

 vive are long-lived, rhizomatous or stoloniferous perennials with extensive 

 root systems, stems capable of rapid upward growth through accumulating 

 sand, and tolerance of salt spray. Although only a few plant species have 

 these essential characteristics, one or more suitable species of beach- 

 grasses occur along most of the beaches of the United States. 



The most frequently used beach grasses are American beach grass 

 { Arrmophila bve-Qiligulatd) along the Mid- and Upper-Atlantic coast and in 

 the Great Lakes region (Jagschitz and Bell, 1966b; Woodhouse and Hanes, 

 1967; Woodhouse, 1970); European beach grass { Ammophila arenaria ) along 

 the Pacific Northwest and California coast (Brown and Hafenrichter, 1948; 

 McLaughlin and Brown, 1942; Kidby and Oliver, 1965; USDA, 1967) sea oats 

 j Uniola paniaulata) , along the South Atlantic and Gulf coast (Woodhouse, 

 Seneca, and Cooper, 1968: Woodard, et al., 1971); panic beach grasses 

 [ PaniGum amaj'um) and ( amcamtum) along the Atlantic and Gulf coasts 

 (Woodhouse, 1970; Woodard, et al., 1971.) 



Transplanting techniques for most species of beach grass are well 

 developed. Transplanting is recommended for areas adjacent to the beach 

 berm and for critical areas - sites subject to erosion. Most critical 

 areas require densely spaced transplants to ensure successful stabiliza- 

 tion. A mechanical transplanter mounted on a tractor is recommended for 

 flat or moderate slopes. (See Figure 6-34.) Steep and irregular slopes 

 must be planted by hand. 



Seeding is practical only when protection from eroding and drying 

 winds can be provided by mulching or frequent irrigation, and is there- 

 fore not applicable to most beach areas. Beach grass seeds are not avail- 

 able from commerical sources, and must be wild harvested during the fall 

 for spring seeding. 



Table 6-1 summarizes much of the information about transplanting and 

 sand-trapping ability of the beach grasses. Additional factors for success- 

 ful transplanting are harvesting and processing of transplants, proper 

 placement of dune, and planting transplants. 



6.441 Harvesting and Processing . The plants should be dug with care so 

 that most roots remain attached to the plants. The clumps should be sep- 

 arated into transplants having the desired number of culms (stems). Plants 

 should be cleaned of most dead vegetation and trimmed to a length of 18 to 

 20 inches to facilitate mechanical transplanting. Plants dug while dormant 

 and held in cold storage may be used for late spring plantings. 



6-43 



