The Netherlands is more than just tulips and sea-dykes

When I look out the window of my workroom at home, several minutes can easily pass without a person being in view. This is quite typical of Swedish countryside. During the times I have been in the Netherlands, however, I have never experienced even one whole minute without a person walking, or more likely cycling, into view. The Netherlands is the most densely populated country in Europe (excluding all of the really tiny countries), with about 500 people per square kilometre of actual land area.

In spite of this, the Netherlands, according to the Statistics Division of the United Nations, managed to be the largest worldwide exporter and re-exporter of fruit and vegetables (including citrus) between 2009 and 2012. The data show that the Netherlands handled 14.6% of the world's total, followed by Spain (12.1%), China (10.9%), Mexico (9.7%), the United States (8.3%), Canada (5%), France (4.4%), Belgium (3.7%), Italy (2.8%) and Germany (1.9%).

Given this unexpected fact, it seems worthwhile to list some of the other facts about the Netherlands that I bet you never knew. Many of the data come from the Eurostat database and the Statistics Netherlands database, but also from miscellaneous other sources on the web.

Bulb season at the Keukenhof Gardens, in the Netherlands.

In this period the Netherlands exported 4,600 million kilograms of vegetables with a market value of 4,200 million Euros. It is worth noting that a considerable amount of the export is actually re-export, particularly of products imported from south-east Asia. Nevertheless, about 24,000 hectares of the Netherlands is devoted to vegetables in total, plus about 19,000 ha dedicated to fruit.

Hardly anyone realizes that the Netherlands is the world’s biggest producer of onions, with 1,353,000 tonnes in 2012. For comparison, Spain produced only 1,169,700 tonnes. The Netherlands is also the leading exporter of button mushrooms (40% of the export market) followed by China, France, Spain, Hong Kong, Taiwan, Indonesia and South Korea. The U.S.A. is the largest consumer, accounting for one third of World production.

The Dutch are the biggest exporters of seed in the world, exporting some 1,500 million Euros worth every year. About 15,000 hectares of land is given over to nurseries and perennial plants, and about 3,000 ha to floricultural crops. Much of the horticultural production is under glass (c. 10% of the area). For example, within the European Union, Spain has about 65,000 hectares of commercial glasshouses, and Italy has c. 35,000 ha; but the Netherlands is third, with c. 10,000 ha.

However, it is bulbs for which the Netherlands is most famous, both as cut flowers and as whole plants. The Netherlands has 86% of the world area for tulip production, with about 10,800 hectares. It also has about 75% of the lily production area (4,280 ha), out of a Dutch total of 23,500 hectares devoted to bulbs. Sales total 1,320 million tulip bulbs per year (1,300 million as cut flowers) out of a world total of 4,320 million (2,300 million as cut flowers).

Tulip season in South Holland. Note the line of tourist camper vans.

The introduction of the tulip to Europe is usually attributed to Ogier de Busbecq, who sent the first tulip bulbs and seeds to Vienna in 1554 from Turkey in the Ottoman Empire. The Turks still tell the story of the first recipients trying to fry and eat the bulbs, rather than growing them! Tulip popularity and cultivation in the Netherlands probably dates from 1593, when the Flemish botanist Carolus Clusius planted his collection of tulip bulbs at the Hortus Botanicus in Leiden. To this day, the area immediately north of Leiden is the heart of the Dutch bulb industry (see the picture above).

However, in spite of all of this plant production, most of the farmland in the Netherlands is actually given over to animals, not plants. Only about 30% of the farmland is dedicated to plants, while 56% is reserved for grazing livestock, as shown in the next graph.

Annual area of Dutch farmland this century. Note the log scale.

Given all of this primary production, it is not unexpected that the Netherlands has the best balance of trade for raw materials within the European Union, with a surplus of 4,500 million Euros per year (see the first network below). This is followed by Sweden (3,000 million). The only other EU countries with a positive balance are Denmark, Latvia, Romania, Ireland and Estonia. Last are Italy and Germany, each with a deficit of -12,000 million Euros per year.

NeighborNet (based on manhattan distance) of the 2001-2012 data for international trade of raw materials
for the member countries of the European Union. Countries near each other in the network have a similar
balance of trade, while countries further apart are progressively more different from each other.

Furthermore, the Netherlands has the second best overall balance of trade (i.e. including manufacturing) in the European Union, with a surplus of 37,000 million Euros per year (see the next network). This is way behind Germany (153,000 million), but just ahead of Ireland (35,500 million). The only other countries to have consistently had a positive balance of trade this century are Sweden, Belgium and Denmark. The United Kingdom has fared much the worst, with a deficit of -116,000 million Euros per year.

NeighborNet (based on the manhattan distance) of the 2001-2012 data for total international trade
for the member countries of the European Union.  Countries near each other in the network have a similar
balance of trade, while countries further apart are progressively more different from each other.

The Netherlands is also famous for having 50% of its alleged land area less than 1 metre above sea level (see the map below); and indeed 20% of the land is actually below sea level. Throughout the latter region, the water flows uphill into the rivers and canals, a feat that is not usually achieved anywhere else on the planet. This has traditionally been accomplished with windmills, of course.

This situation has occurred because during the first millenium AD much of the land was washed out into the North Sea, and during the second millenium the Dutch tried to get it back again. In particular, Lake Flevo became the South Sea, and was then reclaimed as Lake IJssel. These days, rather massive sea-dykes are used to keep the water at bay.

The Netherlands with respect to the Amsterdam Ordinance Level (NAP).

So, where are the Dutch managing to do all of this agricultural production? I suspect that the creators of Dr Who invented the Tardis after a visit to the Netherlands, since clearly the Netherlands is larger on the inside than it appears to be on the outside.

A network of New Zealand's livestock regions

If I was to burrow down from Sweden through the centre of the Earth and keep going, I would come up off the east coast of New Zealand. In spite of being as far apart as you can get on this planet, these two countries have one thing in common — most people don't know quite where they are (Sweden is usually thought to be somewhere in the Alps, and New Zealand apparently exists only as a figment of Tolkien's imagination).

New Zealand is full of New Zealanders, of course (about 4.5 million of them), but according to government statistics it is also full of dairy cattle, beef cattle, sheep, deer, pigs, goats, horses, ostriches & emus, alpacas & llamas, and miscellaneous other farm animals. Indeed, there appear to be as many dairy cattle as people, as many beef cattle as people, and ten times as many sheep as people. This is ridiculous — even Australia has only five times as many sheep as people!

Where are they keeping all of these animals? To find out, I have used a network to explore the official statistics from the recently released New Zealand 2012 Agricultural Census tables, broken down by geographical region. I have restricted the data to dairy cattle, beef cattle, sheep, deer, pigs, goats and horses, as the data are a bit sporadic for the rarer animals; and they are also sporadic for the Chatham Islands, which I thus excluded. Note that the official bureaucratic terms for missing data are "Confidential" and "Suppressed" — the mind boggles at the idea that the number of pigs in or near Auckland, for example, is a government secret. Anyway, I have done my best to impute the missing data (based on the reported totals for each island and on the 2007 census).

The map shows you that the geographical regions vary dramatically in size (compare Nelson and Canterbury, for example), and so I standardized the animal counts for each region using the reported area (to get density, as animals per square kilometre). I then used a double square-root transformation, which is a traditional technique in zoology for standardizing extreme differences in animal abundance.

I then calculated the similarity of the regions using the Manhattan distance. A Neighbor-net analysis was then used to display the between-region similarities as a phylogenetic network. So, regions that are closely connected in the network are similar to each other based on their livestock abundances, and those that are further apart are progressively more different from each other.

The main outcome will surprise no New Zealander — both the North Island (shown in red) and the South Island (in blue) have distinct groups of regions. Indeed, the North Island has two-thirds of the dairy cattle, beef cattle, goats and horses, and the South Island has two-thirds of the deer and pigs, while they split the sheep equally. This means that the North Island has about 22.5 million livestock and the South Island about 20.5 million.

Nelson, West Coast, Marlborough and Tasman, all from the South Island, are the regions with the lowest density of livestock, and hence are strongly associated in the network. The West Coast has the lowest density of all of the livestock types except dairy cattle and deer, which is why it stands out in the network. (It also has the lowest density of people.)

Much of the network is highly correlated with sheep density, not unexpectedly, with increasing density from top to bottom in the graph. For example, Northland and Bay of Plenty, from the North Island, are relatively devoid of sheep, just like Marlborough and Tasman, although there are still 30-40 of them per square kilometre in all four regions. Gisborne, Hawke's Bay, Manawatu-Wanganui and Wellington are the areas with the greatest sheep density on the North Island, along with Canterbury, Southland and Otago from the South Island.

Other positions in the network are often based on single livestock species. For example, Waikato and Taranaki are far and away the most popular areas for dairy cattle; and Waikato and Auckland are the best places to go to see goats (although, at one per square kilometre, you won't see too many). Gisborne and Hawke's Bay are the places to go beef-cattle watching. Deer are particularly popular in the Canterbury, Otago and Southland regions. No-one will be surprised that horses are densest in the region with the biggest city, Auckland, which has one-third of New Zealand's population and 1 horse for every 225 people. (This doesn't even remotely challenge Sweden's national average of 1 horse for every 25 people.)

Apart form the quality of its lamb, New Zealand is world-famous for its vinous products (and its phylogeneticists, although these things are not necessarily causally related). It is probably the grape-growing in Marlborough that is excluding the livestock, since it has two-thirds of the 35,000 hectares of New Zealand's wine-grape area, according to the Agricultural Census. The West Coast is the only region listed as officially having 0 hectares of grapes, but Bay of Plenty, Taranaki, Nelson and Southland are all listed as Confidential (they have less than 55 hectares between them).