Tree of the Month • Black Locust

January 2016 Tree of the Month and Backyard Wisdom (combined)

Black Locust  Robinia pseudoaccacia

by: Gilbert A Smith, ISA certified Master Arborist

Photos by Lesley Bruce Smith

Photos by Lesley Bruce Smith

In the early 1900’s unscrupulous land speculators sold property in the great plains claiming buyers could “strike it rich” farming the vast grasslands. Originally plains looked green and promising in Texas, Oklahoma, New Mexico, Nebraska, and Kansas because although the annual rainfall was only 10 inches the prairie grasses were well adapted. Like all grasses, when the rain stops, they simply go dormant and when the drought ends they green up. (Note, this is the same today with our lawn grasses so we really do not need to water as much as we do.)  The native grasses were tough and the thick roots that were so hard to till, held the soil in place. The modern sod busting plow and tractor, they thought, were just the tools to exploit this treasure. Hundreds of thousands headed west to make their fortune.
In 1929 the great depression struck, causing wheat prices to fall.  In an effort to keep their farms, more acres were plowed and planted. As a result, 1931 saw record production of wheat which ironically drove the wheat prices even lower. Then the drought struck. It lasted in some places for 8 years.  The native grasses would have just waited while their fibrous roots held the soil, but they had all been plowed away.  Without the prairie roots the soil was lifted by powerful westerly winds and blown east in huge dark dust storms as far east as New York City. My father who grew up in the Chicago area said that he remembered the skies were dark brown for days at a time, like dusk all day.  Thousands of Americans lost everything, migrating for work they became known as “The Okies” described in Steinbeck's Grapes of Wrath.

As part of his “New Deal” President Roosevelt established the Civilian Conservation Corps which planted more than 200,000,000 trees from Canada to Texas called shelter belt trees. These trees were also made available for free to the farmers and land owners to plant wind breaks.  

That’s where the Black Locust comes in. A member of the pea family, it’s roots harbor little nodules of bacteria which capture Nitrogen from the atmosphere and make it available for the tree to use. In soils that have been eroded the ability to “fix nitrogen” make this tree a champion.  It is drought tolerant, sterile soil tolerant, wind tolerant and its branches have small spikes that keep grazing animals at bay.  This is how the Black Locust came to Illinois.  You’ll find it on the eroding slopes along Lake Michigan and in long North South lines of sometimes gone farm fields. In the 1970’s farm land value spiked and many farmers removed the shelter belts for short term profit while their soil took to the wind again.

Every tree has a story to tell. The tough Black Locust tells us the story of the perfect storm of greed, failed private enterprise, natural disaster and massive government programs that actually worked. The hardy Black Locust remains today as a living testament to an environmental tragedy and a triumph of conservation.

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