but many of them are already sending new shoots through it. Unless 

 drastic shifts in erosion or deposition rates occur within the next 2 or 

 3 months, an adequate stand of well established vegetation is expected 

 over the area this spring. This is interpreted to be moderately success- 

 ful and to indicate that seeding under such conditions offers promise of 

 rapid and economical stabilization in some cases. 



k. Cost . The cost of propagating S. alterni flora from seed is 

 reasonable and not unlike that of agricultural crops, except for diffi- 

 culties in gathering seed, and for access of equipment to some planting 

 sites. The time required to harvest a known amount of seed was determined 

 at Oregon Inlet in September 1972. One man operated the harvester, while 

 two others removed the cut seed heads from it at the end of each round. 

 Three sample areas were harvested (Tab. 17) to quantify yield of seed per 

 unit area and time required for harvesting. The variability of yield is 

 demonstrated by comparing the first sample area to the other two sample 

 areas. The volume of seed per unit area was about five times greater on 

 the first sample area than on the others, even though it was much smaller. 

 Variability of this magnitude in the seed crop of S. altermiftora is 

 common. Consequently, it is difficult to predict the resources necessary 

 to harvest seed at different locations or years or even different areas 

 within the same stand. In the sample, about 5 man-hours were needed to 

 harvest enough seed to plant 1 hectare. 



The harvested seed were threshed to reduce the space necessary for 

 storage. Threshing required about one-half as many man-hours as harvesting 

 The cost of storage was negligible, since refrigeration facilities were 

 available. 



The amount of time required for planting depends on the equipment 

 available. Using a two-wheel garden tractor for preparing the seedbed 

 and covering the seed after they were broadcast by hand, 4 hectares were 

 seeded by 3 men in about 10 hours. This amounts to 7.5 man-hours per 

 hectare. 



In addition to the times listed there are other variable costs for 

 transportation to the sites, fuel, etc., which are difficult to estimate. 

 Fixed costs (equipment) are also difficult to estimate. In this case, 

 most of the equipment used was modified from that already owned by the 

 Soil Science Department, North Carolina State University. 



3. Site Requirements . 



a. Elevation and Tide Range . For propagation of salt marshes by 

 either seeding or transplanting, care must be taken in selecting or 

 preparing sites which meet the requirements of the species used. The 

 interactions of such factors as tide range, elevation, slope and 

 salinity determine the species of plants present and influence their 

 vertical zonation in marshes. The vertical range of S. alterniflora is 

 generally stated to occur from about mean sea level to mean high tide. 

 There are many exceptions to this generalization. Variations in vertical 



71 



