An Introduction to The Trees of Trinity

by Jessica O’Connor

A brief stroll throughout campus will reveal a treasure trove of trees. It is clear even to an amateur naturalist that there is a vast selection present on campus. These trees from all over the world (yes, really!) manage to survive within the boundary of a city centre college campus and they sometimes make it look easy. While there is a rocky history with the survival rate of some trees, most have managed to remain here for decades. It is hard to imagine the variety of trees on campus, they range from native Irish oak species to Maidenhair trees native to China. Most of the trees on campus are deciduous- meaning they lose their leaves in autumn. Beautiful colour changes during the year help to reveal the true beauty of the trees on our campus. I hope to give you a greater appreciation for the trees on campus with an exploration of their complex history and interesting ecology. 

Walking through the main gate and out into campus, you are greeted by Parliament square. Your eyes are (most likely) initially drawn to the view directly in front of you, Front Square with its imposing architecture and characteristic cobblestone paths. However, if you look to your left and right you will be greeted by another different but just as magnificent view. The tree you are looking at is an Erman’s Birch or as those in the trade call it a Betula ermanii. This tree has a spectacular range stretching from Japan to Siberia. This pair of birches were planted following the loss of one of two Oregon maples in June of 1945 caused by an unexpected storm. After an arduous conversation, it was agreed that the second Oregon maple should be removed, the reason being symmetry. However, if you look to the right the birch present there is much less impressive; this is due to the lack of sunlight it receives in comparison to its contemporary on the left. So, possibly in homage to the cosmetic and therefore unjust removal of the second Oregon maple, lack of symmetry persists. This impressive tree can reach heights of up to 30m. Betula ermanii has shallow roots and is deciduous. The bark, which is pinkish in colour, unfurls  into scrolls at maturity. 

As you approach the east side of New Square, past the museum building there are two trees that may grab your attention. Across from house 36 of The Narrows are two Oriental plane trees, called Platanus orientalis. These trees are native to Greece eastwards to the north of Iran! Their leaves are alternate which means that each leaf is attached to the branch alone. The presence of globular clusters of fruit are distinct markers for this tree species. However, the trunk of these specimens present on campus is peculiar. There is a wart-like swelling present on the bottle-shaped trunk. Astonishingly the girth of the largest specimen is an impressive 5.5m. This trunk width is the widest of any other tree on campus. Notably, this tree is listed as one of the ‘Champion Trees’ of Dublin by the Tree Council. If we transport ourselves back to the Birr of 1834, the 3rd Earl of Rosse planted two Oriental plane trees. Why is this of importance to us? Well, the trees planted by the Earl are significant as they have the same unusual bark leading us to the conclusion that they are of the same origin as the pair of Oriental plane trees on campus. 

Without having to move too far you should come across a Sessile Oak or Quercus petraea. Sessile oak has been designated as Ireland’s national tree as it is a dominant species throughout our native woodlands. It can grow in poor acid-rich soils and is found in Europe and the Balkans. On the 13th of March in 1992 Alderman Sean Kenny, the Lord Mayor of Dublin at that time planted a Sessile oak sapling. The date of the planting marked the 400th anniversary of College Charter Day. However, due to building works taking place the specimen was moved, sadly it did not live on. The National Parks and Wildlife Service generously supplied a worthy successor, which thankfully remains standing today! 

As one heads to the Ussher library observing trees is probably the last thing on their mind, I get it! but if I may draw your attention to the infamous Aesculus hippocastanum or Horse-Chestnut as you and I may know it. This species is native to the mountainous regions of the Balkans but is planted 

around Europe. This tree was planted in the year 1920, unfortunately, we just missed its 100th birthday. Everyone reading probably has fond memories of collecting ‘conkers’ (don’t lie, we all did it!). What you are actually collecting is the distinctive seed of the tree. Interestingly they were fed to sick 

horses by the Turks as the chemical within the seeds was known to have anti-inflammatory properties. But they could make you and I quite ill, unlike regular chestnuts which are edible. 

At the flat iron, there are many different species of tree present but I am going to shine a light on the Maidenhair tree or Ginkgo biloba. This tree is what is known as a ‘living fossil’. It is the lone survivor of a major plant group that thrived during the time of the dinosaurs (Mesozoic). Imprints of leaves in rocks from 200 million years ago are practically identical to the leaves of the living tree. The leaves 

have a fan-like shape and the veins contain a forked pattern that repeats itself. Ginkgo biloba is a deciduous tree, during autumn its leaves turn a golden colour. This species is native to China and wild trees remain, although scarcely in the east. This tree has separate sexes with the male being favoured as when the female reaches maturity the seed coat becomes sticky and a rancid smell develops. The tree won’t begin to produce fruit until it reaches 20 years of age, however, once it does it makes up for the lack of production initially. Interestingly some specimens are thought to exhibit ‘leaky gender’. This means that male/female branches may form on a tree of the contrasting sex. The tree on campus was planted in 1956. 

Although brief I hope this article has given you an appreciation for some of the trees we are lucky to have on our campus. There are still many more to explore! So, I urge you even when rushing to that oh-so-important lecture or meeting up with your friends at the infamous ‘Pav’, stop and look at these magnificent marvels we have right within our reach.

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