The Kentucky Coffee Tree

THE PREDICAMENT OF THE KENTUCKY COFFEE TREE

This is truly a fascinating tree with an equally interesting story. Even the name sparks interest – gymnoclaudus dioicus, ‘almost naked’. This refers to the fact that Kentucky Coffee are similar to the black walnut family in that they are leafless, or naked, most of the year. Don’t confuse these 2 species though, coffee trees do not exude the chemical, juglans, the way that the walnut family do.

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The other part of its Latin name, dioicus, refers to the fact that the trees are separate sexes, male and female. Both sexes will grow to 60 – 75 feet tall and 40-50 feet wide. Their growth is truly quick where in the first 10 years they will rise 12 – 14 feet.

I wanted to highlight some of this species unique traits. For example, they act like a giant sunflower. The leaflets will actually rotate on the stalks and track the sun all day. This is a strategy not to maximize sunlight exposure but, rather, to conserve moisture.

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The seeds of the tree are even more unusual. They are large and extremely hard. I have to use a Dremel drill to nick the seed and, as a matter of fact, most squirrels, rabbits and mice don’t bother trying to eat the seeds. The only 2 creatures I know of that feasted on the seeds were the prehistoric Mastodon and the Eastern Woodland Bison.

Presently, it is a species at risk in Ontario for many reasons. Initially, the population took a beating due to over harvesting. But the nature of the species, itself, has compounded the situation. All trees need a vector whether it be wind, water, birds or rodents to disperse their genetics to new areas. Kentucky Coffee trees have lost these dispersal agents. In addition, the most basic principle for seed germination is water. Water must penetrate any seed coat and enter the embryo. Only the presence of water will rid the seed of its final germination inhibitor. Seeds that are not nicked by wildlife lay on the forest floor for many, many years awaiting the day when water will enter their embryo and trigger germination.

By the 1980’s, most remaining sites of Kentucky Coffee were in jeopardy. These sites were islands surrounded by agricultural activity. No seed dispersal is happening and, therefore, no genetic diversity or genetic sharing between protected sites. The seeds that are produced are not readily germinating. Now, most of the tree populations are uni sexual. The only recovery program that I know of was launched in the mid 1980’s by the University of Guelph where tree representatives of each protected site were gathered and a living gene bank created at the University of Guelph Arboretum.

The value of this tree is just being realized. Cities are just starting to use this tree in their urban landscapes. Toronto has been actively planting this species throughout the city and parks and on private properties. They appreciate its hardiness, resistance to road salt and not being prone to diseases.

Not alone does this tree have tremendous potential as an urban tree but also as a soil reclamation and stabilization tree. In the States, it is planted on mine sites and is used as an alternative tree in areas ravaged by insects and disease to Ash and Elm.

Demand is the driving force in any situation. There is definitely a growing demand for Kentucky Coffee and the only supplies are from imported stock. Growers and nurseries supply the demand by importing stock instead of applying pressure for locally sourced trees. And this is where we spin in circles and end up doing nothing and allowing our local Kentucky Coffee tree population to fade into extinction. Seed collectors, like ourselves, would gladly grow these trees but there is no local seed available. Why? – there are 2 factors that stop us.

The first factor is that the locations of any local coffee populations are guarded knowledge and not readily made public. The second factor is environmental protection laws.

Wish me luck in this quest to find local coffee seeds and grow them. We know that these remaining populations of trees are in severe reproductive distress and that the probable outcome is extinction if there is no intervention. Obviously, waiting for the population to rebound on its own has not happened so maybe it is time for a redirection of action…