Saturday, 3 March 2012

London Plane Tree (03 MAR 2012)

Leonardo da Vinci (1452-1519) lived in Italy during the Renaissance, a time when scientists were polymaths rather than the specialists we recognise today. They understood that the sciences, mathematics, architecture, engineering, philosophy, literature, art and music were all inseparably linked together. Leonardo himself is reknowned for his paintings and inventions but not many people are aware that he dabbled in botany in his spare time. Manuscripts containing his botanical sketches remain as evidence.

One of his observations referenced the fractal growth pattern of trees :
"Leonardo claimed that each year when the branches of plants have concluded their maturation, when added together, the sum total of their cross-section is equal to the cross-section of the trunk."  Enlarge the thumbnail in this page to see a scan of his sketch ...
... and here's a piece of modern art generated mathematically by following this principle.

Some trees exhibit it better ...

          


...  than others ...

                            


A mathematical model created last year questioned the long-standing theory that the fractal form of trees evolved to allow optimal sap flow and proposed instead that this growth pattern is dictated by wind forces.

My cherry blossom tree demonstrates wind resistance in the summer

Trees are an example of covergent evolution. This is when, through generations, unrelated species find the same solution to their problems. Different plants discovered that by developing trunks, they could reach higher, even shading other plants competing for sunlight. The first plants to evolve in this way were similar to tree ferns (with trunks but without branches) or pines with whorls of radial branches around the length of their trunks with minimal signs of further branching.

The next evolutionary steps for trees in climates where there are clearly defined seasons were that the lower branches grew upwards to form crowns for more exposure to light in sunny months, and the trees lost their leaves in wintery months resulting in reduced surface area to prevent damage by winds and snowfall.


“While human ingenuity may devise various inventions to the same ends, it will never devise anything more beautiful, nor more simple, nor more to the purpose than nature does, because in her inventions nothing is lacking and nothing is superfluous.” Leonardo da Vinci


This is my favourite tree in a public place. I posted photos of it in autumn while its leaves were still intact and last month when it was covered in snow, but here it is on a sunny day at the point where winter turns to spring. Please take a walk with me to the tip of the longest branch on the right and then ...











In autumn I didn't know its name, assuming it was a type of chestnut tree.
Its prickly, green fruit were so hard that they wouldn't break under-foot when I trod on them to check if there was a nut inside.

Now they have turned golden-brown and softened to a multitude of fluffy tufts each carrying a seed.   


I eventually classified it by the markings on its branches.
The London plane (platanus hispanica) is a hybrid of platanus occidentalis (American sycamore) and platanus orientalis. It's more resistant to fungal disease compared to its parent trees and thrives in urban areas as it self-cleanses. Its relatively stiff outer bark sheds as the tree expands, removing residual pollutants with it and producing a mottled effect which inspired the khaki pattern used for military uniforms.


I'll return later in the year to see what its flowers look like. I've read that they're inconspicuous, facilitating wind pollination, as these trees belong to an ancient family which evolved before bees and butterflies. Maybe this also explains its strange branch formation, half-way between a fir tree's and a regular deciduous tree's (as in Leonardo's sketch).

He noted that the fractal principle only applies to trees that aren't deformed or haven't been pollarded. Since classifying this tree I've seen several around, they all have symptoms of an irregular (not deformed) shape though they're not as old as the tree above. Maybe he wasn't aware of plane trees ...

I felt uncomfortable publishing this post because it seemed that I had left a loose end, but relaxed after reading these words : 

The elements of mathematics, that is to say number and measure, termed arithmetic and geometry, discourse with supreme truth on discontinuous and continuous quantities. Here no one argues that twice three makes more or less than six, nor that a triangle has angles smaller than two right angles, but with eternal silence, every dissension is destroyed, and in tranquility these sciences are relished by their devotees.
Leonardo da Vinci

I think he's saying that mathematics is just a way to simplify a complex world. Sometimes the rules apply and we can use them to help us learn more; sometimes they don't.


The references that I used for this post can be found by clicking on the blue writing.

Today I'm treading in the footsteps of these tree-bloggers Laura@patiopatch, Donna@gardenwalkgardentalk and Lucy@looseandleafy.

I'll be following this tree through the seasons and linking in with Donna Abel's Seasonal meme.

©Copyright 2012 b-a-g. All rights reserved. Content created by b-a-g for http://experiments-with-plants.blogspot.com/2012/03/london-plane-tree-03-mar-2012.html

27 comments:

Donna@Gardens Eye View said...

It is exciting to have you follow this plane tree through the seasons and to think it is a hybrid of the sycamore here in the states...a fav of mine and quite a wonderful tree...I always learn so much from you!!

Donna@GWGT said...

This was really an informative post. I did not know that it inspired military uniforms, but it is often described as having camouflage bark, which I agree it really looks like it. I also did not know the Plane tree can after the Sycamore. But being around for so long, the Sycamore came before most trees. I love these trees too. Your favorite one is a beauty. I think the Renaissance would have been a remarkable time to be alive. Thanks for mentioning me too on trees. There really is something about them that draws people to them. The world could go on without us, but not go on without trees.

Pam's English Garden said...

Dear b-a-g, Such a very clever posting! You obviously did a lot of research for it. And impressive pictures. I love that quote by da Vinci. P. x

Stacy said...

I really enjoyed the approach, b-a-g, and in more than one way. It's nice to see the tree at a distance and then get closer to see what a fantastic shape it has. Do you have any sense of how old this tree might be?

Croft Gardener said...

Thank you for an interesting post, it is always good to discover a scientifically minded gardener. Mathematics will always provide an insight in to form and structure in living organisms, however in biology there are usually too many variables to make the application of mathematical formulae strightforward. This should not encourage us to throw the text book out of the window it should stimulate us to keep asking questions and to be scientifically curious.

Alistair said...

b-a-g, you are a fascinating guy. I have always been interested in the works of Davinci. Your post brings it to a level away from the usual Mona Lisa, or flying machines for that matter. I certainly do like your favourite tree.

b-a-g said...

You're welcome Donna (GEV) - it's a pleasure to be able to contribute to your Seasonal Celebrations meme.

Thanks Donna (GWGT) - I've always suspected that humans aren't such superior beings.

Thanks Stacy - I don't really want to know the age of the tree - then I can keep imagining that it's hundreds of years old. There's no signpost and I've googled but only found it mentioned in a local artist's blog, not in any official sites.

Thanks & Welcome to Blotanical Croft Gardener.

Thanks Pam - Glad you liked Leonardo's quote. Seems that he was good with words too.

Thanks Alistair ... but Leonardo was the fascinating guy, not me!

linniew said...

That is one awesome tree. And I got all caught up in the Da Vinci website--what a great link, b-a-g. I had never thought of trunks evolving exactly, to boost up the leaves competitively. And for the first time I considered that trees sort of have exoskeletons with the life flowing inside like blood in veins. My final thought was of Ents--hard for my mind to stick with science. But you do help me with that and I thank you.

David Marsden said...

I really like the modern art - not a phrase I use often. And I miss plane trees, they are so very common in London, for the reasons you say, but not so much elsewhere in the UK. I wonder whether they are relatively fast growing? I may plant one, if so, as they are very handsome.

Janet said...

What a very interesting post. Da Vinci was way ahead of his time, wasn't he? And thanks for the link to his web site.
I wouldn't have known much about plane trees before this.

Carolyn @ Carolyn's Shade Gardens said...

All fascinating. I have 15 London plane trees on my property and several of them are that size. I love them but have never noticed the flowers. I will have to be more observant this spring (although the flowers are pretty high up there).

Stacy said...

And yay for your nicotiana header, though the other one was nifty, too, of course!

debsgarden said...

I enjoyed this post! The London Plane tree is magnificent. The earth and its universe functions within the context of scientific laws. I am not surprised that mathematics applies to trees.

Andrea said...

I like this post most especially the last quote by Da Vinci. And i echo what Donna said above. I suddenly thought of the Fibonacci numbers while reading this post, and remembered also the first time Donna and i exchanged messages because of the oaks which do not shed leaves in winter, and why! Now if you will excuse me, just reminding you that Linnaeus might turn in his grave if we dont write the scientific names properly, Platanus hispanica! hahaha! thanks.

Malar said...

The plane is really magnificient! Your photos are really sharp and this post is really awesome! You ahve present it with a lot of research done!

b-a-g said...

Thanks Linnie ... for really digesting this post. I had to google Ents because I've never heard of them. I'm sure my pet tree has a spirit too.

Thanks Dave, I've found a number of sites which label this tree as fast-growing, but they don't state how fast.

Thanks Janet - It's amazing what people achieved before the advent of computers.

Thanks Carolyn - I've passed this tree since I was a child and never noticed the flowers.

Thanks Stacy (again)- the old header took too long to load up (and looked a bit childish).

Thanks Deb & Malar - Glad you like the plane tree too.

Thanks Andrea - Sorry, Plantanus hispanica. I thought you would like the second quote.

The Sage Butterfly said...

This post was so interesting. I learned so much about trees. I have always enjoyed seeing their structure and bones in the winter. Now, I will have something else to see this next winter.

Nell Jean said...

Interesting post. We tend to take our own trees for granted. The only sycamore that I know is the American sycamore with exfoliating bark.

Donna@GWGT said...

Funny you thought tracery a hard topic to tackle because this post is brimming with tree tracery. Your shot of the bare branches against a bright blue sky is a form of tracery in landscaping. It is also how the branching pattern shadows the ground! There is much tracery in the landscape, but it often goes unnoticed, but adds to the overall garden experience, like leaves dappling in the sunlight for instance.

b-a-g said...

Thanks Sage Butterfly - enjoyed your post on Emergence.

Thanks Nell Jean - The American sycamore is one of the parents of the London plane tree. The sycamores we have in the UK are quite different with seeds like helicopters.

Thanks for the tip Donna - maybe I'll be able to join your meme after all ...

Carol said...

Inspiring and fascinating musings! I did not know this about Leonardo. I have long been inspired by Goethe's botanical work and especially his 'Metamorphosis of Plants.' Love the quotes and your photographs of the majestic tree . . . just fabulous! I feel so kindred to your statement beneath the header. Glad to have found your world through Stacy's excellent blog.

b-a-g said...

Welcome Carol ... and thanks for your kind comments. I'm a fan of Stacy too.

If I think too hard about my blog, I feel quite embarrassed about my pathetic efforts compared to the transformations in many gardens out there. I've visited your wonderful blog before ... I've always thought of you as one of the grown-up bloggers and I didn't pluck up the courage to leave a comment. I'm honoured that you visited today.

b-a-g said...

PS. Thanks for introducing me to 'Metamorphosis of Plants'

PatioPatch said...

so glad you are limelighting the London plane, b-a-g with your usual aplomb and unique viewpoint. Makes me wonder if these giants of our public spaces have convergently evolved their towering height to escape assassination by tree hacking council workers? Imagine the earth as water and their reflections will have as much tracery below as on top.

b-a-g said...

Thanks Laura - I hoped you would see this post because your tree-following was my main inspiration.

Alberto said...

I wanted to leave a comment but I realized I have nothing clever to say... I read this post with my mouth half opened. It's always interesting to see things from your scientific point of view!

b-a-g said...

Thanks for the compliment Alberto - sounds like wordless wednesday has got to you!

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