Juglans nigra
Black Walnut

Mature Height: 70-150'     Longevity: 250 years

3-8 Water Range
Soil moisture tolerated by tree

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

DEFENSE     Soil Moisture Key
3: Tree can grow on dry soils & Hydric classification is FACU. Not assign a 2 as tree appears to be much better suited to sites with moisture.

8: Appears to prefer well-drained soils but references indicate occurrence along streams. Silvics Manual also indicates tree can tolerate periods of prolonged flooding.

DEFENSE (from Distribution Maps)
National Audubon Society (NAS) Map: (NORTH) Significant penetration into Z4 in plains states. (SOUTH) Solid Z8 w/ no occurrence in Z9.

Peterson Field Guide (PFG) Map: (NORTH) Same as NAS. (SOUTH) Same as NAS.

6   Sun Strength

3   Shade Strength

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

Click here for Key
5.7 = Moderate - Rapid
0 = Sub-climax
-.2 = 1 Major & 1 Minor
0 = Conflict
+.4 = Yes
+.1 = 85'
+.1 = 150'

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

Click here for Key
2.5 = Intolerant
0 = Sub-climax
-.2 = 1 Major & 1 Minor
0 = Conflict
+.8 = Yes
+.1 = 85'
0 = 250 years

TOTAL SCORE (6.1): Initial growth rate value somewhat shaky, due to lack of data & wide range of growth rates reported for tree (very site dependent). Tree can grow very rapidly on good sites but much more slowly on poorer sites. Member of Juglandaceae family may also suggest growth rate less than rapid.

TOTAL SCORE (3.2): NRCS Plants database intermediate shade tolerance value inconsistent with other data. Allelopath boosts final value.

5   Fire Strength

4   Wind Strength

DEFENSE
Base Score: High (Big Tree) = 5
Tree is very well adapted to fire. Fast growth rate & decent longevity ensure long portion of life as a fire-resistant mature tree.
Final Value = 5

DEFENSE
Base Score: ???
Wood of the tree appears to be fairly strong & the root system deep & substantial. However capacity of the tree to grow very tall with a moderate dbh gives some cause for concern regarding trunk snap or even windthrow. Lack of data or comments regarding windfirmness also unsettling for assigning value. Since has some beneficial wind qualities as well as member of Juglandaceae assign 2nd highest value.
Final Value = 4