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Black Walnut

Scientific name: Juglans nigra

In the first century, Pliny the Elder said, “The shadow of the walnut tree is poison to all within its compass”.  He was referring to the allelopathic qualities of the walnut, which poisons some kinds of plants and trees within reach of its roots and leaves. That said, it has an open canopy allowing dappled sunlight to reach below (where some types of grass can grow).

This native tree is fast growing  and achieves a height of 60-80 feet and a diameter of two to four feet.  Its commercial value is so high, that DNA was used to solve a crime of a stolen Black Walnut tree (the 55 foot tree was worth $2500).  The wood is very hard with a chocolatey brown color and a straight grain. It is prized for its use in furniture and cabinet making. In addition, the nuts from this tree are excellent for human consumption (if the wildlife doesn’t get to it first!).

Fruit

In October the green husks appear and turn brown as they ripen. They encase the delicious walnut inside.

Flowers

In April and May. Male and female flowers on the same tree.

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Habitat

Needs full sun for optimal growth.

Bark

Grey brown to black, broken, irregular, furrowed.

Fruit

In October the green husks appear and turn brown as they ripen. They encase the delicious walnut inside.

Flowers

In April and May. Male and female flowers on the same tree.

Ecosystem Connections

This tree is the host for several different kind of moths. When the caterpillars are feasting on leaves, they will attract birds, who will eat them in turn. Birds often eat insects for their extra protein especially during the breeding season.

Human Connections

This is one of the most highly prized woods of all for its strength and beauty. Over the years it has been crafted into furniture, caskets, gun stocks, flooring and more.

More on Trees and Shrubs in Lewisboro

Lewisboro was once entirely forested except for patches of open field caused by fire and wetlands and ponds which were expanded by beaver dams. Although it is hard to believe, by 1800 most of Lewisboro’s forests had been cut down and replaced by farms. In 1820 so many trees had been cleared that there was no shade anywhere along the route from Boston to New York.[1] But by the mid-1800’s farming here became uneconomical and as farms were abandoned, the forests began to re-grow. Today, 70% of New York is once again forest, what some call ‘the great environmental story of the United States’[2]. These new forests provide us with beauty and recreation, clean air and water, flood control, erosion prevention, carbon sequestration, cooler temperatures and habitat for other plants, insects, birds and other wildlife.

[1] Cronon, William. Changes in the Land. Macmillan, 1983.

[2] An Explosion of Green. B. Mckibben. Atlantic Monthly 275 (April 1995): 61-83.