and Pacific cordgrasses contain large airspaces within their shoots and roots. 

 These airspaces (paerenchyma tissue) allow the plant to store its own supply 

 of oxygen for respiration during submergence (Johnson and York, 1915; Purer, 

 1942). Experiments have also demonstrated that oxygen is transported downward 

 through these tissues to the plants subsurface roots and rhizomes (Teal and 

 Kanwisher, 1966; Wong, 1976). This adaption may allow the lower parts of the 

 plant to carry on respiration and exchange of gasses via the emergent stems 

 even when the plant is partially submerged. Because of this special adapta- 

 tion, cordgrass survives lower in the intertidal zone than any other emergent 

 plant in its range. 



Table 3 summarizes some observations of Pacific cordgrass survival in low 

 areas of the Pacific coast. 



Table 3. Pacific cordgrass survival in lower intertidal zone 

 (Rowntree, 1973). 



Location Tidal range Lowest survivors 



(m) (m, MLLW) 



Bolinas Lagoon, Marin County 1.4 0.6 



Alameda Beach, near Bay 2.0 0.8 



Farm Island 



Palo Alto Marsh, near 2.8 1.3 



Palo Alto Yacht Harbor 



For all practical purposes, shore stabilization efforts on the Pacific 

 coast can use MTL or slightly below as the lower boundary of the planting 

 zone. 



d. Planting Density . Pacific cordgrass spreads somewhat slower than its 

 Atlantic coast counterpart, smooth cordgrass. Consequently, all stabilization 

 projects should use a spacing of 0.5 meter. A 0.5-meter spacing is a density 

 of about 40,000 propagules per hectare. 



e. Planting Width . On sheltered sites, no minimum planting width 

 (landward to seaward) is necessary. On sites exposed to wave action, a 

 practical minimum width is about 6.0 meters. However, at least 60 percent of 

 the upper half of the intertidal zone should be planted. If based on the 

 elevational range of Pacific cordgrass and the slope of the shore, the 

 potential planting area is not 6.0 meters wide, the shore must be graded to 

 provide a suitable planting width. 



f. Planting Date , tforris and Newcombe (1978) transplanted from Pacific 

 cordgrass at monthly intervals and concluded that growth was best from April 

 to August. Early spring planting (April) is preferred for stabilization 

 projects. 



g. Fertilization Requirements . A fertilizer response has not been demon- 

 strated for Pacific cordgrass on fine-textured substrates. However, because 

 early development is critical, fertilization is recommended for all shore 

 stabilization projects unless nutrients availability is certain. 



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