60% 1 Sink Branch = 0.02e4' 60% Parcel B y = 0.02e3.sx
 50% (18 yar r= 0.42 (19 years) r = 0.47
 50 (18 years) < 0.01 50% p < 0.01

 S 40%- 40%

 S30% 30%
 0
 o 20% 0 20%
 0
 10% 10%


 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100%
 Soil Water Content Soil Water Content


Figure 7.15 (Cont.) The Relationship Between Soil Water Content and Organic
 Matter in a Chrono-Sequence of Constructed Forested
 Wetlands. Sites Are Presented in Chronological Order.


SUCCESSIONAL TRAJECTORIES OF CONSTRUCTED FORESTED
WETLANDS


Canopy Trajectories

 Figure 7.16 shows three successional trajectories of canopy tree species based on
ten to fourteen site averages. Figure 7.16a suggests that 83 % of the variation in tree
height is explained by age (r2 = 0.83; p < 0.01), leaving only 17 % of the variation in
height to be explained by other site factors. Sixty-four percent of the variation in tree
dbh is explained by age (r2 = 0.61 p < 0.01). The other 39% is explained by other site
variables (Figure 7.16b). The successional trajectory depicted in Figure 7.16c shows 85
% of the variation in canopy cover is explained by age (r2 = 0.85; p < 0.01).


Subcanopy Trajectories

 There are no trends associated with the subcanopy structure component of the
research sites (Figure 7.17). The data may suggest slightly greater species richness, stem
density and stem diameter of late successional subcanopy species in the youngest and
oldest sites. This trend in older sites may be attributed to age and recruitment. The
occurrence of these species in younger sites is a result of planting.


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