Wednesday 4 June 2014

Tulips....on trees.....

....and other notable Carolinian tree species in southern Ontario.

The Tuliptree (Liriodendron tulipifera) is the unofficial flagship tree species of the Carolinian Life Zone (CLZ) of southern Ontario. The CLZ extends more or less south of a line from about Grand Bend to Toronto, give or take a bit.

And this is the time of year for Tuliptrees to be in flower. The one in my back yard had its first flowers open up on June 3. In some years, they will open even in the last week of May. At Rondeau, with its proximity to the cooling effects of Lake Erie, the average flowering period begins on June 8. In my recent visits to Rondeau, I suspect that it may be a week before the first flowers appear.

From the photo below, it should be clear how this magnificent tree got its name.


This is actually one I took in 2013. The flowers at the lowest and most accessible part of the tree are not yet in full flower.

The Tuliptree grows tall....really tall, and quite straight. It is one of Ontario's tallest trees, growing on occasion to 33 metres or more. However in the heart of its range, Appalachian country, it regularly grows to 50 metres, and on occasion to 60. I recall reading about one specimen in the Smokies that was 67 metres (220')!

The next photo is of what is locally known as the Three Sisters, three Tuliptrees along the.....are you ready for it....the Tuliptree Trail!



This photo which includes my wife will give a sense of scale.

And the view from the bottom.

Tuliptrees need a fair bit of sun....they are not a shade tolerant species. Being as fast growing as they are, they make use of an opening in the canopy to outgrow slower species. As you can see, most of the foliage is at the top where the most light is. Of course the flowers are there as well, which is why you seldom see them. Sometimes the first clue that a tree is in flower is when you see one lying on the ground. Squirrels climb the trees and nip off the flower buds, but some of the flowers tumble to the ground.



They produce a huge amount of seed. But in most years the viability of the seed is extremely low. Germination rates of barely 1% are not uncommon.

There are a few other notable Carolinian tree species in flower now that I will mention.

Eastern Redbud (Cercis canadensis) is often seen on urban and rural properties. In the spring, it is one of the most impressive flowering trees, and it is native to Canada. Not very many people realize that it is native. However it has that status due to a specimen that noted botanist John Macoun collected on Pelee Island in 1892.

If you are driving through most states not too far south of the Ontario border in late April, you will see this species along roadsides, especially adjacent to woodlands. The next photo is one I took several years ago in Shenandoah National Park at the north end of the Blue Ridge Parkway.



The pink/magenta clusters of flowers are truly impressive. I took these about a week ago.


Another rare Carolinian tree is Pawpaw (Asimina triloba). As recently as the 1960s, Chatham-Kent was noted as the stronghold for this species in Canada. It occurred in other CLZ counties, but not as abundantly as in C-K. The extent of upland woodland habitat and the rich soils were perfect for it. Given the loss of woodlands in C-K especially in the last couple of years, I am not sure how many of those populations survive, but that is another story.

The chocolate-maroon flowers are very distinctive, and are open right now, just as the leaves are starting to develop. It isn't a species that occurs at Rondeau. The closest population to the park is along Sinclair Line, especially along the roadside adjacent to the Lower Thames Valley Conservation Authority property at Sinclair's Bush.

Closely related to Tuliptrees is another member of the Magnolia family.....the Cucumber Magnolia (Magnolia acuminata). It is an endangered species, and grows primarily on the sandy soils of Norfolk County with a much smaller population in the Niagara Region.


There are other Carolinian tree species which may be the subject of another post at a time when they are flowering, so stay tuned!

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