Eastern Black Walnut

Basic Information
Tree ID: 
Genus and species: 
"The shadow of the walnut tree is poison to all plants within its compass." --Pliny the Elder (23-79 CE) This imposing tree is located in the gaggle of trees behind 245 Prospect. Unsurprisingly enough, the Eastern Black Walnut is most well known for the fruit it produces--the walnut. While walnuts do not have a strong smell, the leaves, stems, and fruit husks have a spicy odor. Eastern Black Walnuts can live as long as 130 years. Eastern Black Walnuts are allelopathic, meaning that they excrete chemicals that harm competition that is "within its compass."
Nate Swetlitz and Alero Egbe
Collected Data
Tree shape: 
Date of tree entry: 
15.80 m
Diameter at breast height: 
1.06 m

The eastern black walnut's bark is dark and deeply furrowed in a diamond pattern. Link: https://naturallycuriouswithmaryholland.wordpress.com/2012/02/01/black-walnut-2/ Photo from: http://www.rnr.lsu.edu/plantid/species/blackwalnut/blackwalnut.htm
Twigs & branches
The twigs are short and light-brown, with a lighter-colored chambered central portion (pith). Link: https://naturallycuriouswithmaryholland.wordpress.com/2012/02/01/black-walnut-2/ and http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=32. Photos from: http://www.rnr.lsu.edu/plantid/species/blackwalnut/blackwalnut.htm and http://www.alamy.com/stock-photo-eastern-black-walnut-juglans-nigra-view-of-the-treetop-lake-constance-86561380.html.
When the leaves of the eastern black walnut fall off, they leave behind a "scar", visible because the vascular bundles are so much darker than the scar tissue. Photo from: http://www.rnr.lsu.edu/plantid/species/blackwalnut/blackwalnut.htm.
Reproductive Structures
Eastern Black Walnuts are wind pollinated. The anthers and stigmas hang out of the flowers to allow the wind to carry pollen from the male flowers to the female flowers. Male flowers are single-stemmed catkins. The female flowers are on short spikes near twig end and yellow-green in color. Since Easter Black Walnuts possess distinct male and female flowers, self-pollination is unlikely. However, the trees are not self-sterile. Link: http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=32. Photos from: http://www.rnr.lsu.edu/plantid/species/blackwalnut/blackwalnut.htm and http://bioimages.vanderbilt.edu/pages/pollination.htm.
The fruit of the eastern black walnut is round, with a thick and green husk. The husk has a hard nut and is covered in irregular furrows. It has edible, sweet, oily meat that matures in late summer to fall. Tress may produce seed crop after only 4 years of growth. However, large seed crops do not occur until the trees are between 20 and 30 years old. Even then, good seed crops are produced irregularly, averaging 2 good seed crops every 5 years. Link: http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=32. https://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/juglans/nigra.htm. Photo from: http://www.theparklands.org/Blog/151/Can-You-Spot-a-Black-Walnut.
Natural range of distribution: 
The Eastern black walnut grows best in coves and well-drained bottoms, as found in the Appalachians and the Midwest. It does well particularly well along streams and on the lower portion of slopes facing northeast. It is commonly found on limestone soils. It does not do well on wet bottom land and on sandy, dry ridges and slopes. Link: https://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/juglans/nigra.htm
Origin, history, and uses: 

American settlers discovered the eastern black walnut in forest throughout the “New World” using it as fence posts, shingles, sills, and poles because of its resistance to decay. It was heavily harvested, with “walnut rustlers” taking trees in the middle of the night and sometimes even using helicopters to ferret them away. The wood was traditionally used to make solid furniture and gunstocks but in recent years has been mostly used for veneers as the supply has diminished. The nuts are used for desserts - baked goods and ice cream - while the shells are ground and used in a variety of products. 

Flowering and leafing occur around the same time, in about mid-April in the South and can appear anywhere from this time until early June in the northern part of its range. Walnut is monoecious with male flowers developing from auxillary buds on the previous year's outer nodes, while female flowers occurring in short terminal spikes. Female flowers develop before male flowers. They usually do not self-fertilize but, if not pollinated by nearby trees, will set out self-fertilized trees. After pollination, the tree undergoes fertilization, husk development, shell development, and finally seed development. Large edible nuts ripen in the fall, usually September or October, and drop after the leaves fall in the winter.
Media and Arts

The Black Walnut Tree

My mother and I debate:
we could sell
the black walnut tree
to the lumberman,
and pay off the mortgage.
Likely some storm anyway
will churn down its dark boughs,
smashing the house. We talk
slowly, two women trying
in a difficult time to be wise.
Roots in the cellar drains,
I say, and she replies
that the leaves are getting heavier
every year, and the fruit
harder to gather away.
But something brighter than money
moves in our blood–an edge
sharp and quick as a trowel
that wants us to dig and sow.
So we talk, but we don’t do
anything. That night I dream
of my fathers out of Bohemia
filling the blue fields
of fresh and generous Ohio
with leaves and vines and orchards.
What my mother and I both know
is that we’d crawl with shame
in the emptiness we’d made
in our own and our fathers’ backyard.
So the black walnut tree
swings through another year
of sun and leaping winds,
of leaves and bounding fruit,
and, month after month, the whip-
crack of the mortgage.

– Mary Oliver