A hundred years from now the memorial trees you plant will tell the story of the glory of those for whom the trees were planted…

~American Forestry Association, 1919

Picture your hometown.

Big or small, your hometown’s size doesn’t matter…as long as long as it’s more than 100 years old. Do you remember any tall walnut trees next to the town’s oldest streets or public areas? Primary streets change over time, so Main Street today might not be Main Street a century ago. Public spaces don’t change as often. It could even be in your own backyard. Black walnut trees aren’t hard to spot, especially if you have this Handy-Dandy Identification Guide.


Since we don’t want to cut into any trees, we have to guesstimate its age. Black walnut trees live from 150-300 years, and a 100-year-old tree will have a trunk over two feet in diameter*. How do you check without a ruler? Simply put our your arms and give it a big ol’ hug. If you’re an adult and your fingers don’t touch, it’s more than two feet in diameter. *Tree diameters change dramatically depending on growing seasons.

You have a black walnut tree, near a street or public space, and it’s probably 100+ years old. What’s historic about that?


No one had foreseen the industrial carnage of World War I. For the first time, the world witnessed the deadly efficiency of machine guns, tanks, chemical warfare, flamethrowers, barbed wire, and trench guns. For the first time, deaths numbered in the millions—20 million (including 120,000 Americans). When the Great War finally ended, a desolate Europe attempted to pick up the pieces, and American soldiers returned home, bringing with them the 1918 Flu Pandemic. Millions more died.

Nations across the world mourned the back-to-back tragedies. While struggling to pay the bills of a costly war, nations looked for an affordable way to honor the memories of the fallen and the dead. An inspired Great Britain decided on planting “Roads of Remembrance” across their land. These would be picturesque stretches of highway with stately trees planted on either side. Soon the idea spread to Canada, Australia, New Zealand and the United States.

The United States, however, took the idea of planting “Memorial Trees” along “Roads of Remembrance” one step further.  President Woodrow Wilson worried the Great War had depleted America’s stock of black walnut trees. Found abundantly in the United States (even considered a “weed tree” here) black walnut lumber is tough, resists decay, and plentiful. Almost every mature black walnut has 8′ to 10′ feet of clear lumber available (clear lumber has no knots or irregularities, making it easy to work and durable).

Manufacturers made the gunstocks of both the American Model 1917 Enflield and British Lee-Enfield from walnut. Airplanes of that era used propellers made from walnut. War industrialists even discovered the used black walnut shells, when burned and crushed, made excellent activated charcoal for American gas masks. America needed black walnut trees to replenish the tools of war.

The supply of these trees in the United States and overseas had been thinned by the Great War. Many of the European forests that housed these useful trees had been destroyed by the horrors of combat. In 1919, Wilson asked the Boy Scouts of America to catalog the black walnuts across the country. Knowing that a mature black walnut tree needs decades to grow, the government strongly endorsed the black walnut tree as the exclusive memorial tree of the United States.


Wanting to ease worries of yet another war, the government stressed the natural beauty of the tree, its association with Teddy Roosevelt and the American conservation movement, and its preference by revered George Washington, who loved snacking on the cooked nuts.

The program became a tremendous success. All across the country, from the smallest towns to the largest cities, Americans memorialized their loved ones by planting a black walnut tree. The American Forestry Association aided efforts by registering every walnut tree planted and providing a memorial plaque. Each tree would also be added to the published “National Honor Roll Memorial Tree Registry.”

Black walnut trees (sometimes common walnut trees) were planted by the thousands, most often in public places and busy roadways. The United States didn’t create as many “Roads of Remembrance”  as Europe, since most of the memorial trees were planted individually in small towns and cities.

American Forestry Association Registry. February, 1920.

The program faded once Wilson left office. As with any painful memory, the horrors of World War I became more distant and the urgency of planting walnut trees waned. The American Forestry Association continued its “Honor Roll” until 1922, but gradually phased out the registry. The country—and the world—moved on. In the intervening decades, the plaques and purpose of the memorial trees have mostly disappeared. Scattered records of this American Forestry Association registry remain, but most have been lost to time.

Luckily, it is the trees themselves that remain.

Now tall and stately and a century old, these behemoth black walnut trees shade the streets and squares of America’s towns and cities. Their fruit falls and stains the road ways and sidewalk with juglobe, a mild toxin that the key to their survival, poisoning competing plants nearby.

We don’t know how many of these memorial black walnut trees remain. I would guess most do. Although a handful of these memorial trees still have plaques, the planters are as deceased as the soldiers the trees honored.

That said, given the hardy nature of the species, if you’ve got a old black walnut tree in your hometown, and it’s in a public area, there’s a very good chance it was and IS a living memorial to a fallen soldier of the Great War.

Want to Know More? 

Here’s an excellent primary resource on the American technology used in World War I: a report by Assistant Secretary of War and Director of Munitions Benedict Crowell “America’s Munitions 1917-1918” .

Long before industry utilized its lumber, black walnut trees were popular for their delicious nuts. Here’s an excellent article on the tree’s biggest proponent, George Washington. “George Washington and his Walnuts” from Valley Table Magazine.