Saturday, December 31, 2011

Trees Worth Knowing About

An infographic comparing the wise old men of the tree world. 
Detail of illustration of the world's oldest tree.
Detail of infographic
I spent my antipodean Christmas break in Northland - the remote and sparsely populated top chunk of NZ's North Island. I was delighted to discover not just gorgeous scenery but also some cultural gems there. 
Northland, New Zealand

Northland was a crucible of modern New Zealand; here the Declaration of Independence was signed, soon superseded by the controversial Treaty of Waitangi. Here Busby, Hobson, Clendon and Hone Heke battled to protect their interests with flags, contracts, and fire power. And here lives something more timeless than all of those famous warriors and diplomats: Tāne Mahuta, an ancient kauri tree and one of the oldest and largest living things on earth.

Seeing the virgin kauri forest is a moving experience. There is the smell of wet rainforest and the sound of a million tiny creatures fighting their corner of the ecosystem. A giant kauri is not only incomprehensibly vast, it is also smooth, with just a chaotic, spiky crown high above the ground. The towering giant gives an impression of serenity, but it is not thanks to a peaceful nature that kauri have survived since the Jurassic. They have five clever strategies to kick the young upstarts in the shins.

1.Bigger than the rest
Crown higher than canopy.
Sheds lower branches as it grows, avoiding vines.
3.Shed skin to stay bug-free
Flaking bark defends from parasites.
4.Chemical warfare
Acidic litter from bark around base of tree releases other nutrients from clay, stopping other trees from getting them.
5.Scare off the bad bugs, share with the good ones
Acidity, waxes and phenols deter microorganisms which would otherwise rot the kauri, but symbiotic relationship with fungus mycorrhiza helps nutrient uptake, starving competitors.

Before my visit to Waipoua Forest, I was determined not to become a 'tree geek', but I'm afraid it's too late.  I'm in love with Tāne Mahuta and his contemporaries, and I thoroughly recommend you visit Northland.

Saturday, December 3, 2011

The 1376 Census of Sulmona (& Protovis Donut Chart)

Donut Chart
Data viz people love censuses.  They are a mirror for our nations to reflect upon ourselves.  There are lots of modern data viz examples using census data.  But no one seems to have analysed historic censuses.

Some of the earliest censuses which survive today began appearing in the 1200s and 1300s.  I've been enjoying Joseph & Frances Gies book, which explores what these early sources tell us about family life in the Middle Ages.  Since I used to live near Sulmona in central Italy, I had read about the rare Sulmona census of 1376 in Ezio Mattiocco's book.  Signore Mattiocco uses text, and the odd table, to explain the data.  Wouldn't it be great to see some of that visually?

The Gies don't mention the 1376 Sulmona census, so I thought I'd apply some of their analytic approaches to it in my data visualisation exploration.  

To get us started, here's a view of what land was used for in 1376.  The majority was ploughed, but a surprising amount is allocated to wine and hemp.

I created this chart in JavaScript / Protovis, but Blogger doesn't appear to support Protovis, so here's a static image instead.  In the original you can roll over each wedge to see the number of hectares represented.  Thanks to Nathan Yau's Visualize This for the tutorial.