I've just created a new category for this blog: Journalism. [NB: from 03/06 the "Articles" topic] It's a repository for the longer bits of writing I've had published in recent years, and which I think its worth making available on the net as a resource. The pieces are quite long - several thousand words each - but if you have any interest in some of the things we're growing at Limestone Hills, climate change, or terroir, they're worth dipping in to. Because these pieces are not blog items as such, they won't appear on the front page. Just click on the Journalism link in the sidebar. Eventually I'll be adding something like Picosearch to the site, which will help in finding things not published on the front page or in the archives.

This article originally appeared in Growing Today magazine in 2001.

Hot days aren’t unusual in my part of New Zealand. Every summer there are times when it’s so hot that the best I can do is slump into the chair under the big old birch tree and drink iced water while reading a book. I know from experience that if it’s hot round the house, it’ll be even hotter out on the back paddock, and blistering among the olives. Work is futile, destined only to cause sunburn, dehydration and frustration. Before I learned this lesson, I would sometimes set out after lunch to minister to my little truffle trees, only to turn back half way, completely flattened by the heat. It seemed as though the paddock between the house and the truffière concentrated the sun, intensified its power, bleaching the grass and making lizards happy. It was the hottest place on the farm, beyond a shadow of a doubt. An idea formed. Would this be a good place for a small vineyard?

The answer, confirmed by winemaker and wine critic friends, was a resounding yes. There seemed little doubt that I could grow grapes and make wine — perhaps even very good wine. Besides the heat, the paddock is sheltered because it’s in a slight bowl and has the truffière growing to the west. The soil is rich in lime, with good drainage. It is practically frost free, with cold air rolling off the paddock and down a steep gully to the river 30 metres below. It’s not a big paddock. I will not be making a lot of wine, but I’m hoping it will be very good wine, wine that will really reflect the “terroir”.

Terroir is a French word (pronounced “terr- wahr”) that has no direct equivalent in English. It could mean “soil”, or “terrain” or “land”, but French winemakers use it as a shorthand for all the factors that go into making wine from a given vineyard taste the way it does. It’s the total physical and cultural ecology of the vineyard, the interrelationship between the physical factors of soil, sub-soil, drainage, site, climate and microclimate, the vines and their management, and the human cultural factors that go into the making of the wine. To the French, terroir is expressed in the flavour of the wine — the “natural” flavour of the wine. The winemaker aims to allow the wine to express its sense of place; what one American writer has called its “somewhereness”, and the French call “le goût du terroir” (the taste of the terroir).

Recognising a good idea when it sees one, France has now adopted terroir as a concept that can be applied to many things. “Cuisine du terroir” is the trendy new way of describing regional cooking, and “produit du terroir” can apply to just about every kind of food or product imaginable. Taking things a step further, the European Community has begun to recognise this wider use of the term in their Protected Designation of Origin (PDO) scheme. PDO status allows producers to register and protect their regional products — from Jersey Royal potatoes to Parma ham or balsamic vinegar from Modena. All of this is based on the assumption that there is a close link between terroir and taste, and not just in wine terms. It implies that in each area, the terroir is uniquely suited to producing the highest quality apples, pears, cheese, wines or whatever the local speciality is. Terroir, in that sense, suggests that farmers have found the best possible use for the land.

There are lessons in this for growers all over the world. Understanding the terroirs on your property will help you to work with the land as you grow your crops or manage your stock. One field may be right for an orchard, another for grazing. Applying the concept in your marketing will help you to stand out from the crowd, and add real value to your products. On a larger scale, building a regional identity based on the strength of local products will help to strengthen the economy and attract gourmet tourists. Equally, investigating the terroirs in a region can suggest alternative land uses and high value crops that can transform the face of the rural economy. The Southland province of New Zealand is leading the way with its Topoclimate project, a unique attempt to map soil against microclimate, and then to apply that to a huge database of crops. It is already having a major impact on farming in the region. Above all else, using terroir as a concept to inform the way we manage our land is a great way to focus on quality, and that’s something all small growers should be concerned about.

Let’s take a more detailed look at the elements that make up terroir. Underlying everything of course, is geology. The rocks under the land determine the soil that forms on top. The source rock, be it quartz, sandstone or limestone, affects the structure of the soil both in terms of its physical characteristics and its chemical make-up. As the rock weathers under the influence of rain, sun and frost, the particles provide a basis for biology to get going, and a complex community of plants, animals, fungi and bacteria evolves, each characteristic of the site. Being complex stuff, soil can vary a great deal over a short distance, and that can be reflected in the vigour of plant growth — and in the taste of the product.

The physical structure of the soil and sub-soil is equally important. Good drainage relies on water being able to move out of the soil at a reasonable pace, fast enough to avoid waterlogging problems (which can be a killer for many crops), but not so fast as to take water away from the roots before they can use it. Obstructions such as hard-packed layers in the soil or an impervious underlying rock can create problems for plants by restricting root growth, or by causing water to build up in sub-surface ponds.

Other factors, such as the colour of the soil and the amount of stones in it can have a marked impact on plant growth. Dark soils warm up more quickly than light coloured soils, and so can reach critical growing temperatures earlier in the spring, and retain them longer in the autumn. This was brought home to me fairly dramatically when an analysis of soil temperatures in my truffière, where the soil is black, showed that my North Canterbury block was just as warm as one in Hawkes Bay — 500km and 3 degrees of latitude compensated for by the colour of the soil. Stones have an influence on the temperature by warming up during the day, and then releasing their heat during the night. This advantage of stony vineyards has even been used in large colour adverts by a major New Zealand wine company.

Having dealt with the surface and what’s below, the next major influence on plant growth is the shape of the land, and its relationship to the sun. A north-facing slope will be warmer than the flat paddock below it, because the sun’s rays will be nearer to the vertical. The simple truth of this fact can be demonstrated by watching snow melt on hills in winter, or by watching how the grass dries off on the same hills in the summer. It’s also obvious that a north-facing slope will be considerably warmer than one with a southerly aspect. Anyone who has visited Germany and seen the steep vineyards on the banks of the Rhine or Mosel will have seen just how important the lie of the land can be. Those German winemakers are demonstrating the same trick as my truffière, utilising a terroir that’s warmer than you might expect from the raw climate figures for the area.

The shape of the land also affects the movement of air. Hills may shelter crops from damaging winds, or funnel ordinary winds into stiff gales. Cold air will roll down slopes as it cools, and collect in any hollows or behind obstructions, creating frost-prone ponds. That essential shelter belt may also be a perfect frost trap! Windy sites will have different growing conditions to sheltered ones, as people living by the sea can testify, and the effect can vary over a very short distance.

When looking at the effects of weather on the terroir, you have to consider it at a number of levels. Standard measurements of temperature, for example, are made in special white boxes a standard distance above the ground — roughly human height. But the temperature down at ground level can be very different. At soil level, down among the plants, there may be very little air movement, and the effective temperature can be a lot higher than you feel with your head being caressed by a gentle breeze. Similarly, in winter ground frosts are common long before air frost is a problem. And as we’ve seen, the type of soil and lie of the land can have a big influence, as can the kind of vegetation covering it.

Climate is the average of all the weather experienced in a region. This is useful for telling you about average things, but doesn’t tell you much about critical weather events that can determine whether crops are viable or not. A late spring frost can be disastrous for grape growers, damaging flowers and wiping out a crop. An early winter frost can ruin an olive harvest, freezing olives on the tree. Hail is a problem for all orchardists, while heavy rain can erode land, make rivers move their beds, and weaken trees’ hold on the ground. If a gale comes along soon after heavy rain, the toll on trees can be large.

All of the above contributions to terroir are relatively straightforward, amounting to a detailed understanding of each piece of land and its relationship to the weather. There may be a lot of factors to consider, but there’s nothing that can’t be measured, no mysticism involved. But the French concept goes further, and adds humans to the picture. Culture, they say, is as crucial a contributor to the final result as any physical factor. A wine made in Burgundy is not just made from the fruit of a vineyard, it also represents the human input of the winemaker, and perhaps hundreds of years of tradition and experimentation in making wine. A cynic might say that this is their way of defending their wines against upstart New World offerings. An Otago pinot noir may be very good indeed, but it can never be a Burgundy, because it can’t embody all that tradition. It’s a good point, but the Otago vineyard has its own unique terroir, something it can build on and refine (and emphasise in its marketing). That sort of thing is already happening in Hawkes Bay, where a group of winemakers whose vineyards are on the Gimblett Road gravels have formed a marketing association (called Gimblett Gravels, surprisingly enough) to promote their wine through emphasising the benefits of their unique terroir.

The New World advantage, of course, is that we can pick the best of the old and apply it to the best of the new. When a cheese maker with a Dutch heritage begins to make cheese, it’s natural that they should begin with a Maasdam or a Gouda, even if the cows and grass are Kiwi through and through. They are not hamstrung by rules that allow only certain “traditional” methods of production, as are wine and cheese makers in Europe. But there can also be problems. A lack of local knowledge and understanding of crops and products can limit both quality and sales. Traditional methods may help to improve the product, not stifle innovation. In terms of truffles, for example, the average New Zealander wouldn’t know a black truffle if jumped up and bit him on the bum, but in Provence or Perigord, the black truffle is a key part of local cuisine and culture. Towns hold truffle festivals, churches fill for truffle harvest blessings, and restaurants fill with customers eager to experience this seasonal delicacy. The “culture” built around truffles is an integral part of the whole truffle experience, and it’s almost totally lacking here. If there is to be a local market, then growers will need to spend a lot of time educating consumers, and perhaps the clergy. Selling to the French will mean not only delivering a first class product, but appreciating how the truffle fits into their society.

New Zealand is beginning to move more in that direction, as increasing numbers of wine and food festivals around the country demonstrate, but we still have a lot to learn. Last year, I visited the truffle market at Alba, in northern Italy. It was busy (and very smelly), and packed with tourists — mainly wealthy Germans and Swiss willing to spend a small fortune to try the fabled tartufo bianco. Very large sums of money were changing hands for very small bits of fungus. I look forward to the day when wealthy tourists are pouring out of Christchurch airport to pay homage at the Canterbury truffle festival. Not many turn up for the start of the whitebait season!

Terroir is about an intimate understanding of the land and what its best uses are, and I think it could be a key concept in the development of New Zealand agriculture. The patterns of land use you can see as you drive through Europe represent the culmination of thousands of years of farming experience (and quite a lot of EC agricultural policy distortions too, it has to be said). Here, with only a few hundred years of experience, we often lack that detailed paddock-level understanding of the land. It takes brave pioneers to back hunches and try new crops, to take dusty old sheep country and turn it into vineyards or olive groves, generating income, jobs and revitalising whole regions. If we can systematically search for the terroirs throughout the country, as they are doing in Southland, and apply just a small fraction of that knowledge to planting new crops, then the impact on New Zealand’s economy would be dramatic. We might also discover terroirs that are the best in the world for certain crops, much as we already know we can grow Pinus radiata faster than anywhere else, or make Sauvignon blanc taste superb a world away from its French roots.

Beyond land use considerations, applying the concept of terroir to management practises forces growers to think about maximising quality. It can also encourage organic or biodynamic management. One top French winemaker is on record as saying that biodynamic methods are the best way to get the “gout du terroir” in his wines. Randall Grahm, a Californian winemaker and self-confessed “terroirist” reckons that many modern vine management techniques limit the potential quality of the wine. Utilising terroirs is also an approach uniquely suited to small growers. By definition, terroirs tend to be small, and there can be little doubt that it will be a lot easier for the farmer who has 10ha to acquire a detailed understanding of the land’s moods than the farmer with 1,000ha. Small growers are already leading the way in crop innovation. Perhaps it’s time for big farmers to follow.

This was first published by Growing Today in 2003.

A long time ago, in a garden far, far away, I made an attempt to understand “ soil”. I read gardening books, watched TV gardeners, let the dry crumbly stuff run through my fingers, and then gave up — snowed under by the welter of technical terms, detailed classifications and chemistry that had me struggling to remember the stuff I’d learned at school. “Soil” was filed under T for Too Difficult, and I concentrated on just growing things. Luckily, my living did not depend on the results.

Now that I’m, ahem, a “professional” grower, I’ve had to revisit that T file, and make some real effort to understand the difficult stuff. Botany didn’t come easy, because I gave up the plant part of biology at 16, concentrating on animals. I used to be able to do a really good dissection of a worm (my eviscerated rats were, some might say, beautiful), but got completely lost when phloem was mentioned. Latin plant names were a struggle too. None of that mattered too much in the middle of a big city, in the middle of a business career, but when I discovered a mid-life urge to plant tree crops and found myself confronted by grass covered paddocks, re-education became a priority.

My motivation in all this, as regular readers may know, is that I want to grow things that taste good. Truffles, olive oil, wine grapes, walnuts, chestnuts, mushrooms — all of these are (with luck) on the way. Each of them depends on the soil they’re growing in. The soil affects the taste of the stuff I produce, so in my version of reality it has to be important. It’s my biggest asset, and understanding something about that asset has become a priority.

Soil is a small word for a very big topic. It is the living skin of the planet, the product of a complex interaction between rocks, landscape, climate, and life in all its forms. That complexity is what makes it daunting. First, there’s the geology underlying it all, full of odd names for rocks. When the rock gets weathered down into particles, complicated mineral names are bandied around (montmorillonite, smectites, other ’ites and ’anes apparently ad infinitum). Then we get into chemistry, and finally biology, with millions of little bugs and beasties all chewing and digesting their way through the earth. If you thought soil life was all about earthworms, think again. Finally, since soil is a unique product of each place and its climatic history, there are hundreds of place names that are used to describe characteristic soil types. You can rest assured that I am not going to delve too deeply into all this complexity.

It isn’t all science, however. The politics of agriculture also get involved. How you approach your soil says a lot about your farming style. Dose it up with chemical fertilisers, inject it with tear gas as a fungicide, or shun anything artificial, focussing on creating rich, healthy stuff. The “traditional” versus “organic” fence is there to be jumped. But first, the basics.

Soil starts out as rock. As the rock weathers, it breaks down into lumps and grains, and eventually into the particles that form the basic structure of soil. Two processes are at work; physical weathering through the action of heat, water, ice and plant roots, and chemical weathering, where the rock is attacked by air and water, slowly rotting down. These are remarkably powerful processes, if a little slow for us fast-paced animals to appreciate. Freezing water can split rocks just as easily as it bursts pipes, and rock can get very hot in the midday sun. When plants such as lichens and mosses get involved, clinging to the bare rock, they start to capture dust and produce organic debris. This reacts with water, creating organic acids that chew away at the rock. It’s slow but sure. In Russia, for example, a 200 year-old limestone tower was found to have developed no less than 30cm of soil on its flat roof. In New York, 70 years exposure to pollution, rain, heat and cold all but erased the inscriptions in the granite of “Cleopatra’s Needle” — which had happily survived 3,500 years in Egypt’s dry desert climate.

Rock particles don’t always stand still. They can be washed down slopes by rain, accumulating thickly in valley bottoms, or washed miles away by rivers. They can also be blown around the place, building up dunes (called loess, and common in Canterbury). Layers of different particles of various origins can be built up by geological and climatic processes, or — as in much of the North Island — deposited as ash or lava flows by volcanoes.

Soil particles are classified into three sizes. Sand is the largest, silt lies in the middle, and clay is the smallest. Sand and silt provide the structure of the soil, the skeleton, but it’s the clay particles that determine its chemical properties. Compared with sand, clay particles are tiny (under 0.002mm). Clays are the end product of weathering on the minerals that make up rock, and there are lots of different kinds of them. They play a crucial role in determining the availability of nutrients for plants and how the soil retains water, because they have an enormous surface area. Five grams of a clay called allophane has the same surface area as a rugby pitch!

On those surfaces, clays hold nutrients that plants need — potassium, ammonium, phosphates and sulphates. Some are better at it than others: they’re said to have a high “cation exchange capacity”. The surfaces also get coated in water, meaning that clay soils will hold water long after it has drained away from coarser, sandy soils.

One key chemical characteristic of the soil is its acidity, measured in terms of its pH, and that depends on the presence of lime (or calcium carbonate). Pure water is neutral, or pH7.0. Vinegar is 3.1, and Alka Seltzer 8.2. Acid soils restrict the availability of nutrients such as potassium, nitrogen and calcium, whereas alkaline soils can be low in iron, cobalt, boron and manganese. The optimum pH for most plants is somewhere on alkaline side of neutral, which is why adding lime to paddocks is a key agricultural activity in many parts of New Zealand. My truffle paddock, on the other hand, has so much natural lime that the iron levels in the soil are very low, so low that my young oaks suffer from chlorosis. Their leaves turn yellow, and they stop growing. They don’t die, they just get stunted — so if I want to get some good growth I have to go out and given them extra iron, either as a foliar spray or soil drench.

If the physical and chemical characteristics of the soil are complex, that’s nothing when compared to the complexity of the life it contains. Almost everything I’ve read about soil life starts with some staggering numbers: here are some. One millilitre of healthy soil could contain 50 nematodes ,62,000 algae, 72,000 protozoa, 111,000 fungi, 2,920,000 actinomycetes and 25,280,000 bacteria. The fungal threads (hyphae) in one teaspoon of soil would stretch 15km. The weight of earthworms in a healthy dairy paddock is greater than the weight of the cows grazing on it. And so on.

Life not only creates the soil, it is the soil itself — a vast, interlinked web of living things eating each other, cooperating with each other, modifying the soil in a myriad ways, responding to the weather and climate and the plants growing in it. When you dig a hole or plough a field, you’re creating carnage in the soil. The fresh ammonia smell of a newly ploughed field is caused by the death and decay of billions of bacteria.

Some soil bacteria live by decomposing plant and animal wastes, others can “fix” nitrogen, taking it from the air and converting it to a form that plants can use. Actinomycetes are also decomposers, while algae, a sort of single-celled plant, make sugars by photosynthesis. Some fungi are particularly good at rotting down wood and plant material, while others form beneficial associations with plants, exchanging plant sugars for nutrients extracted from the soil by the mass of hyphal threads. My truffles are this sort of mycorrhizal fungus. Animal life kicks in with protozoans and small nematode worms, eating bacteria, and themselves being eaten by larger nematodes. Bigger still, earthworms stir up the soil, mixing layers very effectively, while the grubs and larvae of moths and beetles — such as grass grub and porina moths — feed on plant roots.

Actinomycetes and fungi are also important because they form a kind of organic glue, sticking the soil particles together to create the various kinds of crumbs and textures we find when we cultivate the soil.

Although the numbers may be vast, the biomass of life in the soil may be as little as five per cent of the total organic matter present. The rest is humus, and it’s powerful stuff. Humus is usually described as a relatively stable, dark organic substance derived from the breakdown of animal and plant residues by microbial action. The precise composition of humus is impossible to pin down, as it varies just as much as the soil itself, but it is a hugely valuable source of nutrients for both plants and soil life. In energy terms, it’s a sort of solar battery, acting as a bank for nutrients and energy. One British scientist estimated that an acre of soil with 4% organic matter contained as much energy as 20 tons of coal in its surface layers.

Humus therefore represents an enormously valuable larder for the plants and animals that grow in or on it. It effectively stores surplus energy from the sun, making it available in future years. Humus is also a key part in helping to create new soils, building up as the soil ecosystem develops. A relatively small quantity of humus can turn sandy soils into rich loam, or clay into fertile fields.

If the soil acts as a nutrient bank for the plants we grow in it, and all the animals that live in it, it is also hugely important as a water storage medium. Clay particles, as we’ve seen, can absorb a lot of water, and water is also stored in the gaps and spaces in the structure of the soil. All the soil particles are coated in a film of water, and it’s in this film that much of the soil activity goes on. If the soil becomes totally dry, all soil life suffers — not just my trees. Just as the soil stores energy across seasons, so it can store water, re-charging over winter, and releasing it gradually as plants require it. Obviously, deeper soils with good clay content will do this better than thin or sandy soils.

Soils are also an important heat store, warming up during the day and then cooling only gradually during the night. Air temperatures can oscillate from frost to sweltering in a few hours, but the soil will react much more slowly — and smoothly. In spring, dark soils may warm up sooner than light soils, extending the growing season, and warm soil surfaces can help to protect plants from damaging frosts early and late in the year.

We’ve now looked at all the basic elements that make up any soil — from rocks to earthworms. It’s time to introduce the next level of complexity. Soils have profiles, and like humans, they can vary a lot. A profile describes how the soil changes with depth. At the bottom, you have the parent rock, grading upwards through rubble and stones into finer and finer particles, getting richer in humus, with a layer of vegetation on top. For some of the soils on my property, that’s all there is. The parent limestone has only a thin layer of soil on top. In other parts, the soil formed over the limestone (technically, a rendzina) has been washed down the slope, and overlies gravels. Those gravels were laid down by the river, and themselves cover different sorts of limestone, siltstone and mudstone. Leave the farm to walk to the truffle paddock, and although you may not notice much change in the surface soil, what lies underneath changes in rock type, sub-soil, depth and drainage characteristics. When I finally get my vineyard planted, I expect to be able to see vine by vine variation in vigour, and perhaps flavour, depending on the route their roots take down through all the different stuff underneath.

Soil profiles are obviously affected by geology and the history of the land. Volcanic eruptions leave layers of ash to make new land, glaciers move rocks and soils around, wind leaves drifts of dust or sand, while rivers flood and deposit silt and gravels. But soil formation is also affected by the plants that grow in it, the weather and climate of the location, and the shape of the land. Soils formed in very wet areas such as the West Coast can have the nutrients in them washed out by the continual rain. This process, called leaching, can push the nutrients down into the deeper layers of the soil profile. Soils formed under forests are very different to those formed under pasture, while the shape of the land can determine the thickness of the soil and how it drains. North-facing slopes will be warmer than South-facing ones. It’s a complex interaction.

A good place to see soil profiles is in road cuttings, preferably new ones. A minor interest in soil can add a whole new dimension to long road journeys, though “spot the rendzina” doesn’t seem to go down too well with the children. When you’re planning to plant a new crop, especially a deep rooting crop such as vines or trees, it’s a very good idea to dig a hole to check out the profile. It will tell you a lot about the water-retaining and draining properties of the paddock, as well as revealing potential problems with hard layers that may cause water to pond or be difficult for roots to penetrate. If you’ve got a hard “pan”, you will probably have to deep rip the ground before planting any tree or vine crop.

All of this information about soil structures isn’t much help if we don’t know how the soil interfaces with the plants that we’re trying to grow. Plants take in their nutrients as minerals. They can’t taken in the complex molecules in the humus directly, they have to be broken down into their constituent chemicals first. That’s why “chemical” fertilisers work so well. You’re giving the plant the nutrients it needs in a form it can directly access. The NPK and other stuff just dissolves in the soil water, and is there for the plant roots straight away. That’s why you can grow many plants hydroponically. Put the right stuff in the water, give the plant some support, and away they go.

Out in the wild, plants can’t rely on friendly growers supplying them with food. They have to find their own. A healthy soil, rich in humus, will have plenty of nutrients available for plant growth. Bacteria and fungi will mobilise the humus, and the plant roots and their mycorrhiza fungi will transfer them into the growing plant. The roots, in return, add carbon to the soil through decay and by being eaten, helping to create new humus. It’s a virtuous circle.

Enter the grower. Our aim is take a crop from the field. That could be grass, going into sheep or cows, transforming itself into meat, wool or aged Edam, or it might be olives, apricots, lavender or herbs. Although the energy for the process comes from the sun, we are taking nutrients away from the soil, and if we don’t put anything back, we are effectively strip mining the land. Over the years, the soil’s reserves, found in its humus, become depleted, and as a result the whole complex ecological fabric begins to look a bit frayed. If we choose to address the problem by adding chemical fertilisers, we can get yields up, but as the years go by increasing doses are needed to maintain production, until eventually it becomes too difficult or expensive to grow anything at all.

In my olive grove, I take nutrients and energy out of the grove in two ways — through the wood and leaves in the prunings each winter, and in the fruit I harvest (if the blackbirds don’t get it first). A lot of the stuff that the tree has used to make structure and fruit come from photosynthesis, but a lot comes from the soil. The trees can’t move on to a nice fresh paddock when they use up their own bit of soil, so it makes sense to put back as much as you take out. This is where choice comes in. The “traditional” approach is to add fertiliser, usually in the form of NPK formulations. The “organic” approach looks to enrich the soil by adding humus, trusting that the crop plants will perform well in the rich soil.

Enter politics, stage left. I suspect (or hope) that most readers will, like me, lean towards the organic end of the spectrum. Knowing that the soil is an incredibly complicated ecosystem, it seems sensible that we should feed the whole thing, rather than just the plants. Adding humus, mulching, feeding the microbes and fungi, all ensure that the nutrient and energy bank in the soil is kept in credit. In the long term, keeping your soil thriving with life will keep your crops producing good yields. And they may even taste better…

The Mediterranean Lifestyle, or growing olives, grapes, truffles and things that taste nice in salads… [First published in Growing Today in 2001 - I think].

All things Mediterranean are deemed to be fashionable. The Mediterranean diet cures us of heart disease and lengthens our lives. A Mediterranean lifestyle is something we aspire to. But the Mediterranean is just a smallish sea between Europe and Africa. What people are really talking about is a lifestyle loosely based on the lives and eating habits of peasants on the north coast of “the Med”. You don’t hear too many people waxing lyrical about emulating the Libyan or Tunisian lifestyle. From Spain in the West to Greece and Turkey in the East, the various cultures have developed diets based on using large quantities of olive oil, fresh vegetables, fish and the unstinting consumption of wine. For modern New Zealanders (and many in Australia and the USA), that sounds like a pretty good life. Couple that with warm fuzzy memories of the European leg of your last overseas trip, or that Tuscan or Provençal holiday, and you have the motivation to set about turning your chunk of land into something a little more romantic.

First thoughts turn to olives. The great movement that has seen hundreds of thousands of olive trees planted in New Zealand over the last decade offers an easy way in for most people. Trees are easy to source, presses are springing up all over the country to take the fruit, and the business has a head of steam that makes “ a few olive trees in the front paddock” seem much less of a risk than they might have been a few years ago.

Then there’s grapes. Everyone likes drinking wine, and it must be cheaper to grow your own grapes than paying someone else to do it, right? And what about truffles? They’re a gourmet delight, the black pearl of Perigord, Provence and Umbria, and they sell for NZ$3,000 per kg/US$700/lb. That should help with the mortgage.

The Mediterranean lifestyle is really a “gourmet lifestyle”, based around a range of crops that can produce wonderful food, and perhaps produce some income. That was certainly what my wife and I had in mind when we planned what we were going to do with our property on the east coast of the South Island. Truffles came first (a small obsession of mine), followed swiftly by olives, and we’re now laying plans for a small vineyard. If everything works out as it should, then our property will be financially self-supporting, but just as important to our vision was the idea that we would be able to sit under our big old silver birch, enjoying a glass of our own fine pinot noir with a salad dressed with our own Tuscan-style extra virgin olive oil, with perhaps a few slices of truffle lending their remarkable aroma to a simple roast chicken (free range, of course). We didn’t know, when we started, that we were jumping onto a bandwagon, but I have to say that it’s been an interesting trip.

Lifestyle farming is essentially small-scale, where the realities of managing small plantings of trees and vines are meshed with what the traditional agricultural sector calls “off-farm income” and which you and I know as a career or business life. The economics of lifestyle farming are more “flexible” than fully commercial, large scale operations. Profit may not come top of your list of priorities, but whatever the scale of your operation you will end up having to sell something. There is, after all, a limit to the amount of olive oil that one family can consume, and you don’t need many trees before you go over that limit. The quality of the stuff you produce therefore becomes very important. Small quantities of second rate oil or wine will be very hard to shift in a highly competitive market. Make the oil or wine to very high standards, and while the world may not beat a path to your door, it will be a lot easier to get rid of. And if you are aspiring to the gourmet lifestyle, second best is not going to be good enough.

The Mediterranean lifestyle is inextricably linked with the Mediterranean climate. That means mild, wet winters and warm, dry summers — the climate loved by grapes and olives (and pretty good for truffles). Look at New Zealand’s wine regions, and you have a pretty good idea of where the Mediterranean lifestyle is practical. In most other parts of New Zealand, it’ll be a struggle. Approximations of the Mediterranean climate can be found from the east coast of Northland, through the Bay of Plenty, down the east coast of both islands and into Central Otago — not forgetting Nelson and Golden Bay. The north, being sub or semi-tropical is more humid than is ideal for olives and grapes, and down south lack of warmth in winter becomes a factor. Frost is not in itself a problem (except with very young olive trees), but the timing of the first and last frosts can be. Early autumn frosts can damage ripening olive fruit, and late spring frosts can wreak havoc with fruit set in grapes.

Excessive rainfall should not be a problem in most east coast areas, but the lack of it may be. Grapes, olives, and truffles will all need irrigation during establishment, and in most years you will need to supplement natural rain to get decent crops. With truffles, for instance, you will need to be able to give your trees the equivalent of 30mm of rain in late January or early February, as this is thought to be one of the critical factors in triggering the truffles to form.

Beyond the obvious large scale climatic factors, you have to consider what the French call terroir — the unique combination of soil, landforms and climate that determines how individual plants prosper. It’s terroir, the French say, that makes the difference between an ordinary Burgundy and the one from the neighbouring vineyard that has critics swooning and wine lovers happily paying hundreds of dollars a bottle. Understanding something of the terroirs on your block is a key step in planning your plantings. If you’re starting out, looking for a block to buy, you should make understanding terroir a priority. If you’ve already got a block you’ll have to work within the limits it sets.

Soil is the first factor to consider. Olives and grapes both prefer free-draining soils rich in lime. Truffles are impossible without it. There are very few places in New Zealand that have perfect, unmodified truffle soils — in most truffières copious amounts of lime have been added to lift the alkalinity of the soil the required level (more than pH7.6, to be precise). Olives and grapes are not so fussy, but olives will certainly benefit from extra lime if the soil is very acid (below pH6.0). If in doubt, get a soil test done. With any crop, tree or vine, it pays to know where you’re starting from, and a few hundred dollars for soil tests will be money well spent. Remember that soils can be a patchwork, formed over thousands of years, and can — and do — vary widely over small distances. The soil profile is also important, both in terms of depth and its drainage characteristics. Dig a hole down a metre or two (hiring a digger helps) and look at the profile. That hole will also tell you something about the drainage and water table. If it rapidly fills with water you could have problems, as olives and grapes hate having wet feet.

The next element in the terroir is the local climate. Technically, there three levels on which climate can be described: the basic climate of a region, the mesoclimate of an area within that region, and the microclimate that plants experience at their growing site. In my neck of the woods, the Waipara climate is markedly warmer than the regional Canterbury climate, mainly because a range of hills keeps cool north-easterly breezes away. Those hills also help to create a “hole in the clouds”, increasing local sunshine hours. On the micro level, lots of other factors come into play. The colour of the soil and the presence or absence of stones can markedly affect the speed the soil warms up in spring, and the amount of heat radiated at night. Good shelter can ensure that wind doesn’t cool (or damage) plants, but badly positioned shelter can create frost pockets.

The lie of the land is also important. To maximise warmth, north-facing slopes are the ideal, but landforms can also affect wind directions and strengths. My olives, vigorous young trees that have astonished me by their speed of growth, are developing a distinct lean to the east. Anyone who knows about the Canterbury Norwester will know why — but there’s more to it than that. Southerlies blowing over the top of the hill behind the paddock end up belting the trees from the west as well. Poor blighters — they get no respite.

Information on microclimate may be hard to come by if you’re a newcomer to an area, and it has to be said that sellers are notably optimistic in their assessment of such things. Look at what your neighbours are doing. If they’ve been around a while they may have valuable information, especially about extremes such as floods and early or late frosts. Don’t be tempted to rely on global warming to see you right!

If you’re working with an existing block — one you’ve owned for a few years — then you should have begun to note some of the aspects of the terroir. Areas where frost lingers, or drainage is poor will stand out, as will hot, dry areas or windy ones. Factor all this into your planning, and be prepared to adapt your plans to your conditions. There’s no point in struggling to make plants grow in less than ideal conditions. If your grapes will one make good wine in one year out of five, they’ll be uneconomic in even lifestyle terms. Why put in all that work if the wine’s not worth drinking? Adapt your plans to your terroir.

This learning and planning process should not be hurried. Getting from first thoughts to actually planting the trees or vines should take around 18 months, not least because you’ll have to order plants from nurseries. Then there’s the soil tests, the ripping and poles and wires and irrigation and… the list is not endless, but it is long!

Olives

Before you do anything, decide what you’re going to do with all the fruit you hope to produce. Most people want to make oil, with a few trees to produce fruit for pickling. If so, you’ll need to plant recognised oil cultivars and one or two table olive varieties. Look at what people are growing in your area, read the books and take advice from local oil presses and nurseries. Aim to have a good mix of cultivars, including some recognised pollinators. There’s no easy answer — no universal prescription. If anyone claims to have all the answers, don’t believe them (not even me!).

The number of trees you plant will be determined by the land you have available, and by the amount of fruit you expect to be able to handle. Some basic figures: a ten year old olive tree should produce something like 35kg of fruit (could be less, could be more). So 100 trees will produce about 3.5 tonnes of fruit — a serious quantity to pick and press. If those olives yield 15 percent oil, then you’ll have something over 500 litres of oil to dispose of. Even if you can get through a litre a week, you’ll still have 450 litres to sell.

Once you’ve decided on the scale of operation you’re going for, you can start to plan the grove. As a rule of thumb, for trees you plan to pick by hand (and in a small grove that’s virtually the only option), a spacing of 5m between trees and rows 6m wide is a good compromise. When you plan the layout of the grove, take account of wind direction, and plan the positioning of your pollinators so that the pollen is spread to every tree. Plan the irrigation carefully, and with the help of an expert. There’s nothing worse than planting all the young trees and then seeing them die of thirst because the irrigation system’s on the blink. Good stakes are a must, as is some form of protection from rabbits and sprays. It also pays to “rip” along the rows — a sort of deep ploughing that loosens up the soil and makes it easier for the roots to grow. Do this the autumn before planting.

Planting is best done in spring (after any risk of severe frost has passed), to give the trees plenty of time to get established. Once in the ground, you need to make sure they’re kept watered, and that you keep grass and weeds from competing with the new roots. Organically minded folk will mulch, others will use a glyphosate spray.

For the first few years, the most demanding activity in the grove will be mowing the grass, but after a few years you will need to plan on spending increasing time in late winter on pruning the trees to the right shape (another controversy). You should also monitor the trees growth, keeping an eye open for pests, disease and nutrition problems. Olives are usually pretty robust and problem free if you look after them properly, but regular soil and leaf tests will make sure that things go well.

After a couple of years, you will also start to get some fruit (80g from 250 trees in year two, in my case), and by year four you may have enough to pickle and perhaps to press. By year seven, your crop should be measured in hundreds, if not thousands of kilos, and your harvest will have to be a carefully planned operation. For a couple of years you may be able to get a few romantically minded friends to help out, in exchange for some oil, but as more people cotton on to the fact that the harvest always seems to take place in the middle of winter (earlier in the North), you may need to start paying people to help.

Grapes

A few olives in the front paddock may be no trivial undertaking, but a vineyard in the back paddock is definitely a challenge. Start by working out what sort of wine you want to make. Is your terroir going to produce a good Chardonnay or Riesling, or is it warm enough for a robust red? Don’t try to produce a Coleraine-beater if your site is better suited to aromatic white grapes. Get to know the winemakers in your area, talk to the viticultural experts who are working on vines day in and day out. Don’t be tempted to back a hunch unless you have really good grounds for trying it out. Nevertheless, a small vineyard of an acre or so (0.4ha) is manageable by a family. It’s done all over the Mediterranean, so it ought to be possible here. But be warned, grapes are a demanding crop, and can’t be left to their own devices for weeks at a time as trees can. You may have to spray them at inconvenient times, typically holidays!

A relationship with a local vineyard and winemaker is very important if you are to make any progress with a small vineyard. Someone will have to make your wine once you’ve harvested the grapes. If you can find someone who will hold your hand and take your excess production, so much the better. A key consideration when deciding what to plant is that the effective minimum unit of wine production is a barrel — about 220 litres. You should try and arrange that the numbers of vines you plant will produce juice in the right quantities. For example, the Mendoza clone of Chardonnay is reckoned to be one of the best for producing fine wine. It will yield perhaps 1.5kg of top quality fruit per vine. If 70 percent of the weight of grapes crushes into juice, you’ll need a little over 200 vines to fill a barrel. The yield equation is a bit more complicated than that, however, because quality grapes come from vines which are cropped at low levels. How much you get is dependant on variety, planting density, soil, local climate and weather, and varies significantly from wine region to wine region. That’s why you need to tap into local experience!

With those sorts of questions sorted out, you will need to order the vines well in advance, and get the site prepared. There will be a significant investment in poles and wires to support the vines, and once again, irrigation will be required, at least in the establishment phase. You should start to get commercial crops after about four years, but it’ll be a while before the young vines mature and produce their best fruit.

Managing the vineyard is fairly demanding. It begins in late winter, with pruning. In early years this is designed to get the vines into to the right shape, and then to get the right number of fruiting shoots for the support system and planting density you’ve chosen. In early spring, you’ll be starting your spray schedule. Designed by experts, these are essential to keep nasty fungi away from the plants, and usually run on a 10 to 14 day cycle. The chemicals are not necessarily nasty, in fact experts I spoke to claim that organic management is not too difficult, provided that you keep the plants as healthy and well-fed as possible. Later in spring, you’ll be tying the new shoots into the wires, forming the “hedge” along the rows. Then it’s toenailing — removing the suckers around the bases of the vines, usually with a butcher’s glove or something similar. Flowering takes place in late spring, and cool wet weather (or a late frost) can have a damaging effect on fruit set and therefore yields. By early summer, you’ll be removing shoots as a part of “canopy management”, letting the sun into the fruit. During high summer you’ll still be trimming the canopy, irrigating as necessary up to “veraison”, the point at which the fruit starts ripening. That’s when the bird problems start. You’ll need nets, either along the rows, or in large “lock-out” covers that go over whole blocks. If you like the idea of riding around the paddocks with a shotgun, banging away at birds, now is the time to indulge yourself.

By late summer, you’ll be testing the grapes for sugar content and assessing the flavours in them, keeping the winery informed of progress. Then its time to harvest, and consign your precious cargo to the person who’s going to turn it into nectar. All you can do then is to wait, visiting the winery to taste samples, to see how the wine’s progressing, designing arty labels and choosing bottles.

Truffles

The Perigord black truffle has been a commercial crop in New Zealand for the last five years. Pioneer grower Alan Hall in Gisborne has been demonstrating to local gourmets that we can produce this incredibly aromatic mushroom just as successfully as the French — and that it can sell for very good prices indeed. Last winter, three other truffières joined Hall’s in producing truffles, and the 50 or more pioneers who already have trees planted are looking forward to the business expanding rapidly over the next few years. With luck, we’ll be selling them back to the French at exorbitant prices.

The truffle is an underground mushroom that grows on the roots of specially inoculated trees — principally oaks and hazels. These trees have to be raised from seedlings, so the lead-in to production can be anywhere from five to ten years, but yields can then potentially move into six figures per hectare, so it’s worth the wait. Sadly, mature trees cannot be inoculated successfully.

Before planting, you must ensure that the soil is at the required pH, and if that means adding tons of lime, then get spreading at least a year before you plan to plant. You also need to ensure that the soil the trees are going to grow in is well cultivated and sprayed free of grass before the little trees go into the ground.

Unlike most crops, in the truffière the aim is grow dense, active root systems, because that’s where the fungus lives. The more roots, the more truffle. Once the trees are growing, the annual maintenance involves late winter pruning (hazels are prone to suckering), a spring cultivation of the soil on either side of the rows of trees before bud burst to keep the soil loose and stimulate new root growth, and continual control of grass and weeds. Fortunately, once the trees are growing well, they should form a brulé, or region of bare earth around the tree — a sign that the fungus is doing well.

From mid-summer, watering becomes important, and the soil should be kept reasonably moist throughout the autumn. Truffles should begin to ripen from May onwards, and then its time to get your highly trained truffle hound into action. A properly trained dog is essential for any truffle grower, because the aroma of a fresh truffle, while strong, is a bit difficult for humans to smell through damp earth. Once harvested, the truffle will keep for over a week, so there’s plenty of time to airfreight the aromatic little beasts to top chefs in top restaurants in London, Paris, Tokyo or New York, or to stuff a few slices under the skin on the breast of a good chicken, and roast it.

The working year

An olive grove and truffière both involve the same sort of annual routine; harvesting in winter, pruning in late winter, and general monitoring (and mowing) through the summer. The truffière will also need a spring cultivation, to keep the soil aerated. The workload with either crop is well within the reach of the average moderately fit family, though you’ll need help with the olive harvest when the trees are mature. Both crops can be managed at weekends, provided that your plantings are modest.

Grapes are a different matter. Work is much more spread out through the year, and involves a schedule that can intrude on holidays and other work commitments. If you only have weekends “on the farm” you’ll almost certainly have to have someone local to help out. It might be possible, for instance, for several small vineyards to pool resources, labour and equipment. Another good reason for talking to your neighbours.

Other crops

The list of potential Mediterranean crops is a long one. If you’re after a Provençal feel, then lavender is essential. A little to the West, the Cevennes inland from Montpellier are covered in chestnuts, and figs do well just about everywhere. Aromatic herbs are essential — the rosemary hedge or pot of basil to scent every meal, and citrus — especially lemons — are a very Italian enthusiasm as well as a Kiwi tradition. Artichokes are traditionally grown in the olive groves of Tuscany, and walnuts are important in both French cuisine and Italian liqueurs such as nocino. Pick your favourite foods, and add them to your edible landscape.

Costs

The big question: “How much does it cost?” The answer, unfortunately, involves the length of a piece of string. There are too many variables for me to offer anything other than the broadest of broad guidelines. Getting into olives is the most straightforward. Trees are readily available at reasonable prices (provided that you buy from a reputable specialist nursery), and all the infrastructure such as irrigation, sprays and so on are standard orchard stuff and easy to find. Truffle trees are much more expensive (over $50 each), and production mostly pre-sold, so you may have to wait a few years to get hold of them. Once in the ground, their running costs should be low. Grapes require the biggest investment in infrastructure — poles, wires, and water, and the young vines, being grafted, can be costly. They also need most labour and looking after. On the other hand, you ought to be able to make excellent wine for under NZ$10/US$5 a bottle. On the equipment front, you will almost certainly be able to do without a small tractor — they can be hired for most tasks more cheaply than buying — but a four wheel bike with a sprayer on the back will be essential, especially if you’re planning a vineyard. And a good robust mower…

More than anything, the Mediterranean lifestyle is about a state of mind and a vision. It demands a relaxed appreciation of the pleasures of the table and a refined understanding of how the food gets its qualities, as well as a readiness to enjoy life. You also need the vision to see how little olive trees or tiny truffle oak seedlings will transform into elements of the landscape. For me, it’s not about recreating any one part of Europe — New Zealand has too many of its own strengths for that — but it is about living a life that many in the world aspire to, but few can afford. We are lucky to live in a part of the world where dreams are still affordable.

This article was first published in Growing Today in 2004. It was written in February and March of that year, and probably deserves to be up-dated with the latest research.

Since we bought our little piece of North Canterbury seven years ago, we’ve experienced an El Niño drought, a La Niña drought, an in-between drought, a once in 100 year flood, a once in 50 year frost and enough wind to make any tree grow with a lean. I’m looking forward to finding out what an average year’s like. Is our climate changing? I don’t know, I haven’t been here long enough to say, but the weather has certainly kept me interested.

This year we’ve had a blistering Christmas and New Year with near record heat, then a cold and wet February, bringing catastrophic floods to the south of the North Island. April brought snow to low levels, at least a month or two early. The National Institute of Weather and Atmosphere (NIWA) reports that 2003 was notable for the number of extreme weather events, and overall it was warmer than the long term average. Some interpret this as a sign that climate change is happening, others insist that it’s all part of the natural variation in our weather. In fact, it’s probably both at the same time.

The world is warming up. The evidence is now very strong indeed. 16 of the 17 hottest years since records began have occurred since 1980. The 1990s were the hottest decade ever. 2003 tied with 2002 as the second hottest year on record, slightly behind 1998. In New Zealand, the annual average temperature has increased by 0.7C over the last 100 years. Every season except spring is showing signs of increased warmth, and there’s been a significant reduction in the frequency of frost. In Alaska, winter temperatures have warmed by more than 4C in the last 30 years. Studies in Britain have shown that autumn lasts longer and spring arrives earlier now than 100 years ago. The cause, according to the Intergovernmental Panel on Climate Change (IPCC), the body of scientists convened to study the issue, is increased levels of greenhouse gases (carbon dioxide, methane, nitrous oxide, water vapour and others) in the atmosphere. Large quantities of those gases are produced by human activities — burning fossil fuels, animals belching methane, and chopping down (and burning) forests. In other words, human activity is causing the world to warm up.

Greenhouse gases warm the earth by trapping the sun’s heat, like the glass in a greenhouse. If the Earth had no atmosphere, the average surface temperature would be a rather brisk -18C, as opposed to about +15C. Globally, carbon dioxide is the most significant of the greenhouse gases, but in New Zealand, methane produced by sheep and cows is also important, not least because it’s 30 times better than carbon dioxide at absorbing energy. NIWA estimates that our animals produce around 1.5 million tonnes of methane a year (mainly by belching, not f*rting). A typical dairy cow produces 370 litres of methane per day, a sheep about 60. You could drive a car for 4 km on one cow’s daily gas production — which might open up interesting prospects for dairy farmers with large herds.

It’s carbon dioxide that’s grabbed the headlines though, because the amount in the atmosphere has been steadily increasing. Before the industrial revolution, CO2 made up about 280 parts per million by volume of the atmosphere. In 2003, the Mauna Loa observatory in Hawaii recorded 373 parts per million, a 33 percent increase. Last year’s figure was 3 ppm higher than in 2002, far exceeding the average annual increase of 1.8 ppm over the last decade. There are suggestions that this large leap has been caused, at least in part, by Asian countries that have been industrialising rapidly, with China in particular building large numbers of coal-fired power stations to keep its rapidly expanding economy going. Felling and burning the rainforests in SE Asia and Brazil doesn’t help, either.

Working out what an increasing greenhouse effect means in terms of the weather and climate we can expect over the next 50 to 100 years is not straightforward. Forecasting New Zealand’s weather from day to day is a notoriously difficult process — trying to look a week or so into the future is about the best we can get with modern techniques. Climate is what you get when you add up and average out all our weather (something plants are very good at), so a climate forecast is like a weather forecast that tries to look years ahead. Doing it on a global scale doesn’t make it any easier — there are a huge number of variables that have to be factored in. However, advances in the models that meteorologists use for weather forecasts (which form the basis of the global climate models, or GCMs), and rapid improvement in the power of the computers used to run these models, has allowed climate scientists to steadily improve their projections of what our future climate might be like. If the amount of greenhouse gases carries on increasing, the world is going to get warmer. Depending on how much CO2 and methane we pump into the air, the IPCC’s last forecast (in 2001) estimated that the world could warm by anywhere between +1.5C and +5.8C by the end of this century.

This doesn’t mean that everywhere will be 1.5C warmer all the time. The GCMs suggest that warming will be greatest at the poles, which fits rather neatly with recent observations of thinner Arctic ice, ice sheets breaking up in Antarctica, and warming in Alaska. Down here in the southern hemisphere, the oceans around us will tend to moderate the rate at which we warm up. Dr David Wratt, NIWA’s lead scientist for climate change, and a member of the IPCC’s advisory bureau, says that New Zealand will probably warm up at about two thirds of the rate of the rest of the world. “The models show increased westerlies” he told me, “and that will mean more rain in the west and on the mountains, and drier conditions on the east coast.” A tendency for the east coast to become drier is likely to increase the frequency and severity of droughts. “Irrigation issues will become very important” says Dr Wratt. Rivers that are fed from the Main Divide such as Canterbury’s Waimakariri or Otago’s Clutha could carry more water, but rivers that rise to the east of the Alps could have problems with low flows.

The increase in average temperatures will not mean the end of cold weather, just that it will become less likely. The difference between an ordinary summer and a warm summer can be as little as 1C in average temperature, so if we get an increase of that order, then what we now regard as warm summers will become “normal”. Very hot weather will also be more likely, which will add to the severity of any water shortage problems. The number of degree days will increase, and therefore the growing season in most regions will be longer. On the other hand, the winter snowline will rise, which could cause problems for ski-fields.

Beyond the increasing warmth, there is also the probability that extreme weather events will become more common, and possibly also more severe. “Extremes have important effects” says Dr Wratt, “frost, drought and floods can all have a dramatic impact. There have already been statistically significant increases in the frequency of heavy rainfall in parts of the northern hemisphere, and there’s some evidence of changes here.” By the second half of this century, a flood currently regarded as a once in 40 year event could become a once in 20 year event. Frosts already seem to be declining in frequency and severity, and average night temperatures have risen. This doesn’t mean that unseasonal frosts won’t happen — frost-prone vineyards will still have to be careful — but it does suggest that they should become less common. However warmer winters aren’t always good news. A 2001 report on the likely impacts of climate change on New Zealand agriculture by Dr Gavin Kenny suggested that in 50 years time Bay of Plenty kiwifruit growers could be having problems with a lack of winter chilling. Some crops will tend to shift southwards, and new crops may become economically viable. Bananas could thrive in Northland, olives in Dunedin. Some recent research suggests that parts of South Canterbury and Otago will become suitable for commercial vineyards. Perhaps even Southland could join the wine boom.

Extra heat will bring with it changes in the distribution of pests. Sub-tropical grass species could spread south through the North Island threatening a reduction in pasture productivity. Damaging insect pests could extend their range, or new pests arriving from overseas could find our warmer climate more to their liking. It isn’t all bad news, however. Increased CO2 in the atmosphere will tend to encourage faster plant growth, at least in the short term, but this will be limited by water and nutrient availability. In other words, crop plants may grow faster, but will require more fertiliser inputs and greater irrigation. Pasture production could be boosted, at least in part because of the longer growing season. Fewer damaging frosts will be good news for growers of many crops. And people who have been climatically rather optimistic in the choice of crops they’ve planted may strike it lucky.

To explore how farmers and growers might respond to climate change, a two year study is being carried out in east coast areas, under the aegis of the Hawke’s Bay Climate Change Adaptation Group and Dr Kenny. Workshops were held last year in the Bay of Plenty, Gisborne, Hawke's Bay, Nelson, Marlborough and North and South Canterbury, and farmers were asked what issues they might face and how they might respond if the climate had warmed 1C and rainfall dropped by ten percent by 2050. The positive benefits participants foresaw included opportunities for diversification and land use change, a longer growing season with less winter feed needed for stock, a “kinder” climate for humans, and farmers being able to respond to change by adapting their farming systems. The challenges included managing water supplies for irrigation, the changes to pasture, crops and livestock, possible negative effects on animal health, changes in weed, pest and disease prevalence, and the potential for social problems arising from more stress, some from the impacts of land use changes. The report on the workshops, called The View From The Ground — Adapting To Climate Change in Eastern New Zealand, makes interesting reading, and gives a sense of the resilience of the farming community in the face of this latest challenge.

If climate change in New Zealand turns out to be relatively gentle and gradual, farmers and growers should be able to respond and adapt. “There are issues to be concerned about” says NIWA’s Dr Wratt. “Adaptation is the key, and the best way to do that is to think on a local level.” Sensible strategies will vary from region to region and property to property, but people in high rainfall areas should be thinking about coping with more, while dry properties will need to plan for less rain and more drought. Things will be tougher if temperatures increase faster than the bottom of IPCC prediction range, and the potential for significant damage caused by extreme weather events will certainly be important on a regional level.

There is a danger, however, that the global climate could do something other than warm gradually. There is evidence from ice cores in Greenland that in the past the northern hemisphere climate has made rapid flips from warm interglacial to ice age. In some cases it could have happened in as little as ten years. This change is believed to triggered by a change in ocean currents, normally driven by water cooling and sinking in the far North Atlantic. If this sinking stops, the warm current that keeps Europe’s winters relatively mild could switch off, leading to a rapid cooling of the European climate — especially in winter. The last time it happened, 12,700 years ago, it ushered in a 1,300 year cold spell. Summer temperatures in Britain averaged only 10C and winter temperatures plunged to -20C. Until recently, scientists believed this was a relatively small risk, and any cooling effect might be relatively minor — just enough to offset the continued warming. However, new data from the Atlantic is suggesting that we may be nearer than expected to a flip from warm to cold. The risk of sudden, as opposed to gradual change is certainly there, but how big that risk is remains to be seen.

This sort of rapid change would clearly be catastrophic for the northern hemisphere, devastating European agriculture and causing unimaginable economic and social problems. What would happen to the New Zealand climate in those circumstances is not clear. Perhaps our oceans would buffer us against the worst excesses, but we would not escape the economic consequences of global climate dislocation.

For the time being, the odds seem to favour gradual change, and in those circumstances New Zealand is probably as well placed as any country in the world to cope with and adapt to a warmer climate. On a local level, I am already hatching schemes for more water storage to give my trees and vines a buffer against drought, and if we’re going to get more Norwesters, I’m going to plant more shelter. If there’s a risk of more extreme weather, perhaps I should do a bit more to stabilise some of the gullies on the property. Just good land management, and sensible insurance against a warming future.

Science, controversy, and politics

Most climate scientists agree that the world is warming up, and that man’s activities are causing it. Some scientists, and many lobbyists (who are often funded by oil and coal companies), disagree. Despite the weight of evidence and the effort that’s been put into the study of the global climate in the last 20 years, a few still try to pick holes in the data and rubbish the predictions. Climate change “sceptics” claim that climate change may not be real, or that if it is, perhaps the sun’s causing it, not us. New Zealand has its share of sceptics, and no shortage of people who would like to believe them. This where science and politics mix, and the results are often messy.

The argument runs like this. If the world is warming up, and we’re causing it, we ought to do something about it. That “something” is the Kyoto protocol, which - oversimplifying considerably - is an international agreement to restrict greenhouse gas emissions. But if the world isn’t warming, or human activities have nothing to do with any warming that is happening, then we have a good excuse for doing nothing - certainly nothing inconvenient or expensive. Many countries, including New Zealand and the European Community, have decided to apply the Kyoto rules, while others, notably the US and Australia, are hanging back. Kyoto, they say, is bad for business. The domestic New Zealand debate is polarised along roughly left/right lines, with anti-Kyoto voices coming from some farming and business lobbies, while support is to be found amongst environmentalists and the Labour government. Complicating the issue is the fact that Kyoto on its own will not bring down CO2 emissions enough to reduce warming by much, and from a New Zealand perspective, our contribution to the world’s greenhouse gas emissions is tiny. But can we afford to do nothing? The science suggests no, but any answer is inevitably political.

Web Resources

There is an immense amount of information (and disinformation) on global warming and climate change available on the web. The New Zealand government’s climate change website is: http://www.climatechange.govt.nz/. On it you can find all the official publications relating to climate change in NZ, including papers on possible impacts by region. The report “The View From The Ground” covering the east coast farmer workshops is available as a pdf download from the “Impacts” page.

The NIWA website also has lots of useful information.

The full text of the latest (2001) report from the Intergovernmental Panel on Climate Change is available at http://www.ipcc.ch/

If you want to find out what the US climate change sceptics are saying, check out The George C Marshall Institute website at http://www.marshall.org/index.php, or the Greening Earth Society at http://www.greeningearthsociety.org/. The latter organisation is funded by “municipal electric utilities [and] their fuel suppliers”.

To get an overview from the other end of the spectrum, Greenpeace has a lot of useful information at http://www.greenpeace.org.nz/. The World Wide Fund for Nature also has lots of info at http://www.panda.org/about_wwf/what_we_do/climate_change/index.cfm.

You can even help to run the computer models that are used to predict future warming. The Oxford-based climateprediction.net project (http://www.climateprediction.net/index.php) allows you to download a programme that runs in the background on your computer, using up spare processor cycles to calculate future climate scenarios. The site is also a good source of information about climate modelling in general. So far, they have received 20,000 completed forecasting runs, simulating a total of 1.5 million years of weather.

[Added May 2006] A good site to learn about current climate science is Real Climate. It's run by working climate scientists.