30 



Examples of FTI numbers by life stage for woody species are pre- 

 sented in Table 5. Although differences between FTI numbers for tree 

 and sapling life stages are not great, FTI numbers for saplings tend to 

 be slightly higher than for trees because saplings are generally more 

 sensitive to flooding than trees. The sapling life stage also tends to 

 occur in a broader range of zones than the tree life stage due to tem- 

 poral variations in selective pressures (e.g., competition and response 

 to flooding) . FTI numbers of seedlings have little value in determining 

 hydrologic zones because they only reflect seed dispersal potential and 

 germination wherever seedbed conditions are favorable. For example, 

 seedlings of least tolerant species (e.g., Sassafras albidum) 



Table 5 



Variations in Species Flood Tolerance Index Numbers 







According: to Life 



Stage 





Scientific Name 





Tree 

 2.97 



Sapling 

 3.33 



Seedling 



Taxodium distichum 





3.09 



GlediCsia aquatica 





3.50 



3.15 



3.27 



Carya aquatica 





3.54 



3.70 



3.69 



Quercus lyrata 





3.73 



3.99 



3.80 



Fraxinus pennsylvanica 



4.44 



4.27 



4.00 



Quercus nuttallii 





4.50 



4.50 



4.50 



Acer negundo 





4.83 



5.20 



5.58 



Celtis laevigata 





4.84 



4.37 



4.77 



Liquidambar styraci 



flua 



5.03 



5.52 



4.87 



Quercus nigra 





5.73 



5.92 



5.85 



Sassafras albidum 





6.50 



6.50 



6.07 



