environmental variables are suitable for vegetative productivity, then soil organic matter
should increase with time as plants grow and die. As organic matter is added to the soil,
bulk density should decrease. Since most sites are constructed with mineral soil,
increases in organic matter should be apparent and should be greater in wetter and more
productive sites. If wetland hydrology has not been successfully established, this trend
my not be discernible.

 By selecting those sites, which have been determined from the results of this
 study to have a greater than average probability of supporting wetland plants, the trends
 in both increases in organic matter and decreases in bulk density should become more
 apparent. Those sites falling below the average, as shown in Figure 7.7, were selected
 and it was inferred from these data that these sites are wetter than average. Figure 7.29
 shows the relationships between soil organic matter and age (r2 = 0.70, p = 0.08) and the
 relationship between decreasing bulk density and age are even stronger (r2 = 0. 97, p =
 0.002).


 SUCCESSIONAL TRAJECTORIES OF EMERGING PROPERTIES

 Tree growth rates can vary greatly, depending on site environmental conditions,
and the chronological age of a site, more than likely, does not describe adequately the
influence of canopy trees on self-organization. Trees, as they grow, increasingly interact
with driving energies (sunlight, nutrients) and modify the environment. Below-ground
competition for soil resources and above-ground competition for light increase as trees
increase in size. Trees are what make a forest a forest and provide a proportionally
greater feedback to the self-organization of the community. The combination of
community basal area and canopy cover are fairly simple parameters that, when
combined, can quantify the influence of trees on the surrounding community.

 Community basal area (of trees greater than 5 cm) has been reported for several
forested wetland types in Florida. Davis and others (1991) found 35.66 m2 ha', 27.68 m2
ha- and 38.89 m2 ha-' in cypress domes, bayheads and hardwood swamps, respectively.
Community basal area in all constructed forested wetlands in this study was less than 10
m2 ha-1. Figure 7.30 is a graph of the best-fit line to community basal area over time in
constructed forested wetlands. The best-fit line can be extended to the horizontal line
representing the community basal area of hardwood swamps (Davis and others 1991).
The horizontal line may be considered the target or goal for constructed forested
wetlands. Figure 7.30b represents a hypothetical trajectory (based on Figure 7.30a), that
was modified to represent a shift to a logistic growth curve. The constructed forested
wetlands in this study are quite young in comparison to natural wetlands.

 Community basal area alone is insufficient to adequately describe the influence of
trees on self-organization. Depending upon site conditions, trees may be allocating
greater resources to diameter at breast height and less to canopy development. Trees that
are competing with other species for light may allocate greater resources to height than
diameter at breast height. Tree density can also influence percent canopy cover. A dense


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