Be a Mastodon today, grow Kentucky Coffee Trees for tomorrow: A homeowner’s guide to germinating Kentucky Coffee tree seeds
by Kristen Sandvall
Kentucky Coffee Tree (Gymnocladus dioicus) is a Species At Risk in Ontario, with only a handful of natural populations left across its natural range. There are various theories as to why this tree is so rare today. Despite its rarity Kentucky coffee tree, has gained popularity in urban landscape due to its tolerance to insects, disease and drought.
One of the most common theories is that the Kentucky coffee tree needed megafauna, large extinct mammals, to eat and disperse the seeds. By ingesting the seeds, megafauna such as mastodons and giant ground sloths, broke down the hard seed coat with their stomach acid, allowing them to absorb water and germinate after being dispersed through the megafauna droppings! With human intervention we can mimic the seed-dispersal abilities of megafauna and help these seeds grow!
These trees belong to the Legume family and are actually related to Cover, Beans and Peas! Their seeds are contained within a large, brown pod, resembling a stout, wavy bean, 4-8 inches long, containing 1-5 large round seeds, about 1 inch in diameter. **Do not confuse these pods with the small, more twisted bods of Black Locust or Honey Locust (seeds less than half an inch in diameter), or Catalpa (pods are longer than 8 inches, and perfectly straight and not flattened).**
Coffee Tree pods hold onto female trees typically throughout the winter months and begin to drop to the ground in the early spring. You may find these pods under trees planted along boulevards, in municipal parks, or even in your neighbor’s yard (make sure to ask for permission to collect seed!)
Extracting the seeds from the pods can be a bit sticky, so gloves are recommended. Once you have your seeds, you will need to scarify them. This just means removing some of the hard seed coat to allow water inside. Nurseries that scarify thousands of seeds at a time use a concentrated acid soak (up to 24 hours in 98% sulphuric acid!), as this mimics digestion by a large mammal.
For propagation at home, there are other, less hazardous methods of scarification. One of the quickest ways is by carefully filing or sanding off a patch of the seed coat. If you have a small rotary tool for sanding, these work well! If you don’t have access to such a tool, try regular hand file, or some sandpaper (with a little extra elbow grease). Whichever method you choose it’s very important to do this carefully as to prevent injury to your hands. For added safety if when using mechanical methods, you can hold the seed with vise-grips while grinding the seed coat down. You only need to file down a small patch of the seed coat enough to let water in.
After scarifying your seeds, soak them for 24 hours in water (pseudo-stratification). At the end of the soak your seeds should have expanded to 2-3 times their size. The seed coat should be much softer now and you will see some of the outer, clear seed-coat peeling off. If your seeds are still very hard and did not expand you can repeat the filing step a bit more and repeat the soak process. Once you have nice plump, expanded seeds plant them in your favourite potting soil about 1 inch below the surface. Seeds will germinate in full sun within 2 weeks. With continued care, you can accomplish the work of a mastodon, and grow a rare, Carolinian shade tree for your yard!
Biodiversity is a sound investment, and I don’t just mean that metaphorically.
Every species on earth represents a unique way of coping with the world around us, and each has evolved a unique set of tools, or adaptations to help it do so. Some tools to help find food, mates, tools that help resist pests, and tools that increase a species’ ability or cope with unpredictable change; some species are better able to cope than others.
Environmental change can comes in many forms, and at every scale. From the draining of a wetland, to the crash of an asteroid. But no matter what the cosmos have thrown at it, life always seems to find a way, seem to overcome these disturbances, but how?
When conditions change, plants and animals have three options. They can vamoose, decamp. They can migrate, and disperse to a more favorable region. If there’s enough time, species can evolve new traits and strategies to cope with their new conditions: they can adapt. But if a species is not able to either migrate or adapt, they may face local extinction.
The ability to adapt is crucial for life on earth to cope with changing climates and land uses. The greater the variety of adaptive solutions, the more likely that one will be successful at thriving under new conditions. Since every species has a different approach to coping with change, the existence of each increase the likelihood that a solution, effective at coping with climate change for example, will arise.
Similarly, for species to persist through change, they must have the capacity to adapt. There must be adequate genetic variation within the gene pool from which natural selection can draw upon to select for newly adapted traits. Fragmented populations are less resilient to change, in part because they are not receiving a flow of new genes from surrounding populations for new adaptations to be derived. So when we talk about biodiversity, we mean the variety of species, but also genetic diversity present within a species, essential for the maintenance of future viable populations.
UN Decade on Biodiversity
So important is this biological diversity to the resilience of our plant to future change, that the United Nations has declared 2010-2020 the international Decade of biodiversity. It sounds fantastic, but what does that actually mean for you and me and the rest of the biosphere?
The most powerful part of this declaration is its call to action. The official website reads:
“Each day counts. The actions taken by individuals, stakeholders and governments are important steps, one building on the other, towards protecting the life support systems that not only ensure human well-being, but support the rich variety of life on this planet.” Basically, governments and individuals now not only have an obligation to protect and enhance biodiversity, but are officially mandated to do so under international law. Make no mistake, this is some serious business.
Specific targets have been outlined in their Strategic Plan for Biodiversity, but they boil down to five main goals: