You see many wonderful, tall conifers around the Arboretum, that resemble the common Christmas trees you see everywhere for this festive celebration. But wait a second, what is a conifer?
All seed-producing plants can be roughly categorised into two major plant groups: angiosperms and gymnosperms. There are some rare exceptions: Gingko trees produce seeds but do not belong to these two groups.
Angiosperms produce also flower, so they are also called flowering plants. Their seeds are enclosed in a fruit, like an apple tree. In contrast, gymnosperms do not produce flower, and their seeds are naked on the scales of the cones.
They also have different leaf and wood properties. Angiosperm trees are usually deciduous (losing their leaves in winter), and they tend to be slower-growing, making their wood density higher. These are called hardwood. On the other hand, gymnosperm trees are usually evergreen, their wood density is lower and produce softwood.
Angiosperm seeds are enclosed in fruit, but gymnosperms do not.
Angiosperm trees usually have broad leaves, but gymnosperms usually have needle or scale leaves.
<aside> 💡 There are many angiosperm and gymnosperm trees in the Arboretum. For example, Japanese maples, oaks, hazelnut, birch, willows are all angiosperm trees. Pines, cypresses, spruces, giant redwood, yew are all gymnosperm trees.
</aside>
Most of the Christmas trees you find on the market are conifers. In fact, they are so popular that the British Christmas Tree Growers Association estimate that around 7 to 8 million trees are bought each year. The usual Christmas tree size takes about 10 years to grow.
When getting a real Christmas tree, we usually have three things to consider: first, are they high maintenance? Some trees drop needle easily; second, do they produce a nice scent? third, what is the shape of their branches and are they strong enough to support the ornaments?
There are too many species of Christmas trees on the market, here are a few examples:
Nordmann firs are the most popular Christmas trees in the UK. It is excellent for retaining needles (and not dropping all around your floor). They orginate from the Caucasus mountains in Georgia and Turkey.
Norway spruces have been popular since Victorian times. It has a rich coniferous fragrance, broad base, and bushy habit. However, it drops needles easily. To help improve needle retention, the tree should be placed away from sources of heat and supplied with plenty of fresh water.
Douglas firs are native in the North America so it is less common in the UK. It has one of the best aromas among Christmas trees when crushed.
After all, should I buy a real or a fake Christmas Tree? Revisit this Oxford Sparks podcast in which I was interviewed last winter, and listen to me talking about the two sides of the coin. We will think about this question in many aspects: carbon footprints, waste disposal and recycling, local forestry and livelihoods, and possible alternatives.
Should I buy a real or a fake Christmas tree? | www.oxfordsparks.ox.ac.uk
Click here for the podcast transcription.
Listen to the podcast on YouTube. You can also subscribe the Oxford Sparks podcast channel 'Big Questions' on iTunes or Spotify.
Although in the podcast last year I said I was not going to buy a Christmas tree, I changed my mind this year. I am buying a real Christmas tree from a local tree farm. Merry Christmas!
<aside> 💡 This is the end of the digital guide. Thank you for joining us for the Walk today! 😄
</aside>