1968). Removing the organic layer (ground litter and vegetative cover) with 

 fire also increases evaporation losses from macropore water. However, nutrient 

 storage in sandy soils on gentle terrain, as in the southern coastal plain, 

 suffer no appreciable losses by sheetflow erosion (Fahnestock, 1973). Soil 

 heat is temporarily increased by fire; critical soil temperature is 100 C 

 (212 F), above which most soil organisms die. However, high temperatures 

 associated with fires are of short duration and penetrate only the first few mm 

 of soil (Daubenmire, 1968). 



As a regulatory factor influencing the ecological succession of biotic 

 communities, fire is of paramount importance on the coastal plain uplands. 

 Dominance of the prairie grasslands over the woody components of brush and 

 forest is maintained, in large part, by periodic fires. The mechanisms that 

 are involved are presented in the treatment of coastal grasslands. 



Several other aspects of the abiotic system are important. Soil heat is 

 an important regulating factor for several physical/chemical/biological pro- 

 cesses including, for example, .evaporation and microbial activity. Soil heat 

 is a function of insulation, regulated by the darkness of the soil color 

 (concentration of organic materials) and by vegetative cover. 



Soil aeration is an important limiting factor of plant and microbial 

 growth. It is regulated by soil structure, soil water, and the churning 

 activities of the soil macrobiota. Sufficient gaseous exchange must occur 

 between the soil and the atmosphere to satisfy the respiratory requirements of 

 root biomass (Costing, 1956; Spurr, 1964). 



Wind-borne salt spray is an important limiting factor affecting plant 

 competiton (Costing and Billings, 1942; Boyce, 1954). It restricts plant 

 growth in nearshore locations to those species best adapted physiologically to 

 tolerate the desiccating salt and wind. Constant exposure to salt spray results 

 in zonation of vegetation with the most salt-tolerant species found nearest 

 the shoreline. Rain washes accumulated salts from plant surfaces into the soil. 



Maritime woodlands . An ecosystems diagram for the maritime woodland is 

 presented in Figure 3-2. The maritime woodland is the edaphic climax community 

 of the coastal uplands (Johnston, 1955). There is no evidence that after be- 

 coming established this system is ever replaced naturally by subsequent serai 

 stages. This community is a variant of the coastal evergreen forest, from which 

 many species have been removed by salt stress. Characteristic vegetation 

 includes many evergreen and aromatic trees and shrubs. The dominant tree 

 species is live oak ( Quercus virqiniana ). Associate subdominants usually in- 

 clude yaupon ( Ilex vomitoria ), red bay ( Persea borbonia ), wax myrtle ( Myrica 

 cerifera ), and laurel oak ( Quercus laurifolia ) (Bourdeau and Costing, 1959). 

 This subsystem has low ecological diversity as compared to other inland forest 

 sites (Bellis and proffitt, 1976). A complete list of common and scientific 

 names used in this text is found in Appendix C. 



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