CHAPTER 6 



MANAGEMENT AND HARVEST 



6.1 IMPACTS OF DISTURBANCE 



We shall first consider the impacts of distur- 

 bance under many conditions in the natural forest to 

 attempt to explore the interrelationship of the multi- 

 ple factors that govern the ecosystem's functions. A 

 better understanding of the cedar wetland's native 

 state should provide a rational basis for its manage- 

 ment. 



6.1.1 Fire and Water 



The major parameters of disturbance in- 

 volve water (its depth and the duration of flooding or 

 drought) and fire (its intensity and duration, w/hich in 

 turn depend on the velocity and direction of wind; 

 water levels; available fuel, e.g., slash, brush, ex- 

 posed dry peat; and other factors). Fire has both im- 

 mediate and long-term impact. The destructiveness 

 of a fire is inversely related to the amount of water 

 present. For instance, at lower water, more peat 

 burns. The deeper the peat burn, the lowerthe possi- 

 bility that viable seed will remain in the forest floor, 

 and the lower the possibility that a new cedar stand 

 will develop. However, a light fire at high water tends 

 to eliminate shrubs and brush, and favors cedar see- 

 dling germination and survival. For detailed dis- 

 cussion, see Little (1946, 1950, 1953, 1979); Little et 

 al. (1948a,b); and Windisch (1987). 



The relationship of Atlantic white cedar to fire 

 and water appears paradoxical: cedar stands are 

 destroyed by fire, but light fire clears competition 

 from the substrate surface, permitting cedar 

 reproduction. A very hot prolonged fire at low water 

 burns off peat, which can result in more standing 

 water Cedar seedlings are drowned by flooding; 

 mature trees are stressed by permanent inundation. 

 However, flooding severe enough to kill undergrowth 

 prepares a seedbed favorable to cedars, and high 

 moisture content is essential for cedar reproduction 

 and growth. 



6.1.2 Other Factors 



Other disturbances in the natural forest are 

 caused by storms (windthrow, ice damage, salt 

 spray, saline water incursion). Deer browse can 

 destroy young stands; herbivory by mice and rabbits 

 has less impact (Little 1958). The girdling and felling 

 of cedars by beaver are of minor importance com- 

 pared to the beavers' major hydrological alterations 

 that destroy or create cedar habitat. Currently, by far 

 the most significant influence on the creation and de- 

 struction of cedar wetlands by natural forces is the 

 slow rise of sea level. The effects of the natural rise 

 of sea level and of man-induced saline incursion are 

 discussed in Sections 1.4 and 2.2.2 (Hackensack 

 Meadowlands in northern New Jersey). 



In each episode of disturbance, history is in- 

 trinsically a factor, as the cedar community at each 

 site is adapted to a particular range of water, light, 

 weather, etc., regimes. An abrupt change is, by it- 

 self, a stress factor Flooding a dry site or drying a 

 flooded site will shift the existing balance between 

 species, whereas continuation of the same situation 

 will leave species ratios unaltered. 



A series of sketches and flow diagrams il- 

 lustrates some of these interactions (Figures 25 - 29). 



6.1.3 Anthropogenic Influences 



Suburban encroachment . Studies in the 

 New Jersey Pinelands (Ehrenfeld 1983; Schneider 

 and Ehrenfeld 1987) indicate that suburbanization 

 eliminates the characteristic cedar-associated 

 species and erodes water quality. Residential 

 development is accompanied by an increase in 

 species richness, with an initial increase in drier-site 

 species followed by a large increase in non-in- 

 digenous species as native plants disappear. 

 Regional water chemistry is strongly influenced by 

 surface inflow of storm drainage carrying heavysedi- 

 ment loads and by septic tank eutrophication. Water 



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