Fraxinus americana (White Ash)

Fraxinus americana functions well as a shade or street tree and a home for squirrels and birds. The wood is useful for construction of sporting equipment (namely baseball bats). Their diamond-shaped wood arises from bark fissures that occur as the tree ages. Unfortunately, these, and every other North American native Fraxinus sp. tree is in great peril from the Emerald Ash Borer infestation.

Fraxinus americana (White Ash)
Family: Oleaceae
Subspecies: ‘Autumn Purple’ (personal favorite, maroon/burgundy fall color), ‘Baltimore Ash’, ‘Greenspire’, ‘Jeffnor’, ‘Jungiger’ ‘Skycole’
Native: North America
Hardiness Zones: 3-9
Height: to 30 meters
Diameter: to 18m canopy spread, trunk to 1m
Root System: thick, woody, hard surface roots common with adults
Growth Rate:
Age: to 300 years, usually to 260
Deciduous: yes, late emerging and quickly falling foliage
Monoecious/dioecious: considered dioecious, rarely monoecious?
Monocot/dicot: dicot

Tolerates: urban pollution, especially once established,
Problems (major): Emerald Ash Borers*
Problems (minor): ash borers, lilac borers, carpenter worm, oyster shell scale, leaf miners, fall webworms, ash sawflies, ash leaf curl aphids, fungal leaf spots, powdery mildew, rust, anthracnose, cankers, ash yellows, brittle branches susceptible to breakage
Poisonous: No

Soil requirements: slightly acidic (less than 6.8 pH), organically rich, well-drained loams or clays
Air Requirements: somewhat tolerant of urban environments
Watering requirement: medium
Sun requirement: full sun required
Leaves: opposite, pinnately compound, 7-9 leaflets , dark green with white underside (particularly veins), lanceolate/ovate leaflets, entire leaf to 38cm
Flowers: dioecious (either male/female), flowers green, purple, or even black, inconspicuous, appearing after foliage develops
Fruits: winged samaras are 1-3 inches long, light green turning tan, seed takes up 1/3 of total fruit space, jingle in wind like keys
Seeds require stratification: yes

Notable characteristics:
This ash tree commonly has beautiful dark purple, golden, or yellow leaves in autumn. Its outer, older bark creates diamond shapes as the tree grows (more noticeably than F. pennsylvanica). White Ash trees are commonly confused with Green Ash trees. Green Ashes grow faster, hardier, and more commonly widespread than White Ashes. White Ash trees generally have longer leaves, a grayish-white coating beneath leaves, and buds sit “in” leaf scars from the previous year in a C-shape (Green Ash buds sit atop leaf scars, making a D-shape). The White Ash is one of the tallest ash trees in North America. Identification requires looking at buds primarily (leaves and bark less determinant).

Uses:
Previously used for lawn shade trees, street trees, campus trees, and park trees. Unfortunately, the enormous prevalence of the highly fatal Emerald Ash Borer has largely inhibited the success of this tree, as well as every species of ash tree native to North America. Many different types of sporting equipment (such as baseball clubs) are made from White Ash wood. Unfortunately, their commercial value has been reduced due to many insect and disease issues that have arisen. Squirrels and birds tend to nest in them, as ash trees often attract many residents.

Sources:

Emerald Ash Borer articles

Fraxinus_americana_autumn
Beautiful fall color, Carbondale Illinois
Fraxinus_americana_bark
Bark
Fraxinus_americana_SIU
F. americana, Carbondale

DSC05465
A single leaf, with seven leaflets, atop a mature stump

DSC05456
A mature tree killed off my Emerald Ash Borers 😥

20150820_083656
Terminal bud, axillay buds immediately below and facing upwards (not outwards)

20150820_083715
9 leaflets per leaf, white undersides clearly visible

20150820_083819
Previous bud sitting “in” previous leaf scar

20150820_084024
Form, young White Ash
All of the images provided were taken by me. They may be used for educational/informational purposes only, provided that this article/online journal is appropriately cited first.

Advertisements

Leave a comment

Filed under Plant Analysis

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s