Betula nigra
River Birch

Mature Height: 60-100'     Longevity: 100 years

3-9 Water Range
Soil moisture tolerated by tree

4-8 Temperature Range
Hardiness Zones in which tree naturally occurs.

DEFENSE     Soil Moisture Key
3: Identified as having some drought tolerance. Harlow & Harrar and Silvics Manual indicate tree has ability to grow on drier soils at least occasionally.

9: Frequently identified as being present around streams, ponds & even swamps. Flood tolerance only identified as moderate among bottomland species but Fire Effects (FEIS) database statistics indicate very flood tolerant.

DEFENSE (from Distribution Maps)
National Audubon Society (NAS) Map: (NORTH) Solid Z5 w/ enough presence in Z4 to warrant its inclusion. (SOUTH) Solid Z8, no Z9.

Peterson Field Guide (PFG) Map: (NORTH) Solid through Z5 w/ significant presence in Z4 in Northern plains & Wisconsin also up state NY. (SOUTH) Solid Z8 no presence in Z9.

7   Sun Strength

2   Shade Strength

DEFENSE
Growth Rate:
Succession:
Soil Range:
Salt Tol.:
Allelopath:
Avg Height:
Max Height:

Click here for Key
6.5 = Rapid
+.3 = Pioneer Capable
-.5 = 1 Minor
+.2 = Moderate
0 = No
0 = 70'
0 = 100'

DEFENSE
Shade Tol.:
Succession:
Soil Range:
Salt Tol.:
Allelopath:
Avg Height:
Longevity:

Click here for Key
2.5 = Intolerant
0 = not climax
-.5 = 1 Minor
+.2 = Moderate
0 = No
0 = 70'
-.5 = 100 years

TOTAL SCORE (6.5): Ability to pioneer & some salt tolerance overcome limited soil type occurrence.

TOTAL SCORE (1.7): Limited soil range and very short longevity ensure very limited effectiveness in shade competition.

4   Fire Strength

4   Wind Strength

DEFENSE
Base Score: Moderate-high (Big Tree) = 4-5
Branch free bole is short often with several stump sprouts. Bark can be relatively thick in mature trees & ranked as intermediate in fire protection in one study. Commonly found in some areas where fire is relatively frequent but most often in wetter areas. Short longevity. Seems to be better suited to intermediate fire tolerance than high fire tolerance.
Final Value = 4

DEFENSE
Base Score: ???
Moderate sized tree with strong wood. Proportionally large trunk. Literature does not suggest frequent windthrow or trunk snapping. Tree is highly disease resistant and any limb loss would likely result in only minor long term damage. No information about roots little other information about windfirmness prevents me from giving a higher value.
Final Value = 4