Seneca and Cooper, 1971.) After cold treatment, the seed should be dried 

 and stored under cool, dry conditions until planting. Seeding date should i 

 coincide with temperatures best for germination — 65°? night, and 85°F days. 

 Best growth of seedlings occurs with daytime temperatures between 80°F and 

 90°F. (Seneca and Cooper, 1971.) 



6.445 Disease and Stress . Beach grasses vary in their tolerance to 

 drought, heat, cold, disease, and parasites. Plantings of a species out- 

 side its natural geographic zone are vulnerable during periods of environ- 

 mental stress. American beach grass is more susceptible to scale infesta- 

 tion when exposure to sand blasting is reduced. Deteriorating stands of 

 American beach grass, due to scale infestation { Evioooaaus oarolined ) , 

 have been identified from New Jersey to North Carolina. (Campbell and 

 Fuzy, 1972.) South of its natural geographic zone (Nags Head, North 

 Carolina), American beach grass is susceptible to heat (Seneca and Cooper, 

 1971), and a fungal infection (Marasius blight) is prevalent. (Lucas, 



et al., 1971.) 



South of Virginia, mixed species plantings are desirable and necessary. 

 The slow natural invasion (6 to 10 years) of sea oats into American beach 

 grass dunes (Woodhouse, Seneca and Cooper, 1968), may be hastened by mixed 

 species plantings. Thus with better vegetation cover, the chance of over- 

 topping during storms is reduced. 



Sea oats and panic beach grass occur together throughout much of their 

 natural geographic zone. Mixed plantings of sea oats and beach grass are 

 recommended since they produce a thick cover and more dune profile. i 



6.446 Planting Width . Plant spacing and sand movement must be considered 

 in determining planting width. When little sand is moved for trapping, 

 and plant spacing is dense, nearly all sand is caught along the seaward 

 edge of the dune and a narrow-based dune is formed. If the plant spacing 

 along the seaward edge is less dense under similar conditions of sand 

 movement, a wider based dune will be formed. However, the rate of plant 

 growth limits the time in which the less dense plant spacing along the 

 seaward edge will be effective. The following example illustrates the 

 interrelationship of planting width, plant spacing, sand volume, and rate 

 of plant growth. American beach grass planted on the Outer Banks of North 

 Carolina at 18 inches and outer spacing of 24 to 36 inches accumulated 

 sand over a larger part of the width of the planting for the first two 

 seasons. By the end of the second season, the plant cover was so extensive 

 along the seaward face of the dune that most sand was being trapped within 

 the first 25 feet of the dune. 



American beach grass typically spreads outward by rhizomatous (under- 

 ground stem) growth, and when planted in a band parallel to the shoreline 

 will grow seaward while trapping sand. Thus, a dune can build toward the 

 beach from the original planting. Seaward movement of the dune crest in 

 North Carolina is shown in Figures 6-35 and 6-36. This phenomenon has not 

 occurred with the sea oats plantings in south Texas (Figure 6-37) or Core 

 Banks, North Carolina. (See Figure 6-38.) 



6-46 " 



