27
THE AMAZING VALUE OF SHELTER

As every farmer (but perhaps not every city person) knows, stock need to be protected from wind in winter because wind greatly aggravates the effect of cold. This connection between wind and temperature is often referred to as the wind-chill factor. We humans are well aware of the wind-chill factor. It is a matter of simple physics that in cold weather we lose heat more rapidly if our bodies are exposed to wind. Moreover, the stronger the wind, the faster we lose heat and the more we suffer from the cold. Sheep and cattle suffer from wind in precisely the same way. It has been found that even if sheep are insulated with a coat of wool three centimetres thick they will still be affected by wind. Hence the importance of windbreaks.

For newly born lambs, wind is a matter of life and death. As sheep farmers know well, lambs unlucky enough to be born on a day when it is cold, wet and windy are liable to die, especially if they are small or weak. Twins and triplets are particularly vulnerable. Some research has shown that lambing losses are halved if adequate shelter is available. At Lanark, the results have been even better. Lambing losses fell dramatically when our ewes began lambing in the sheltered paddocks. Today, thanks to the abundant shelter available, lambing losses have almost been eliminated, a fact that my son David confirmed for me just the other day.

My other son, Patrick, David’s twin brother, has learned from experience about the importance of shelter. Patrick and his wife, Bronnie, run Vasey Farm, the property that belonged to Cicely’s family, the Gaussens. I referred in an earlier chapter to a research report by an RMIT student, Warren Shaw. In this same report, Shaw recorded a conversation he had with Patrick about the trees at Vasey Farm. He asked Patrick why he thought trees were important on rural properties. Patrick replied, ‘The most important thing in this area is the salinity . . . then shelter. Because of the wind storm of ’87, a neighbour lost 2000 sheep in a matter of two to three hours.’ How many sheep had Patrick lost during that same storm at Vasey Farm, a property with an abundance of trees and windbreaks? Patrick’s answer: just 22 lambs.

Windbreaks are important on grazing properties for another reason: sheep and cattle eat more when they are cold. In fact, this is the way they keep warm: by stoking their body furnaces with more and more fuel. It follows from this that stock protected from wind will burn up less of their feed in trying to keep warm and, therefore, put on weight. Here is one statistic I have seen quoted: sheep will be 30 per cent heavier if the velocity of the winds that they are exposed to can be reduced on average by half. The bottom line is that farmers who have their paddocks sheltered from wind will need less pasture to get them through the winter in good health. This in turn has various implications for the farm. Farmers can run more stock, safe in the knowledge that there is enough feed for them. Or they can save on buying hay and other supplementary fodder.

Winter storms take the greatest toll on sheep. In my own district, there have been three storms in the past 30 years that caused mass deaths of sheep—in 1982, 1983 and 1987. Some farmers lost 1000 sheep or more in one storm, yet on neighbouring farms where sheep had good shelter, losses were minimal. In most cases, the shelter was provided by shelter belts of trees or woodlots. Occasionally, it was provided by remnant vegetation.

Lambing remains a big problem, however—at least for sheep farmers. Nowadays, most sheep farmers prefer late winter as their lambing season, although some still choose to lamb in the autumn. Farmers who do the latter face an obvious problem: providing the ewes with enough feed to get them and their lambs through the long winter months ahead when pastures have minimal growth. Lambing in late winter is not free of problems, either. On the contrary: over the years, certainly in many areas of Victoria, there have been horrendous losses of lambs at this time because of the cold.

Lambing losses are a very old problem, of course. As I remember myself, it was the subject of endless discussion in the mid-1960s and various government authorities became involved in the search for a solution. There was a lot of interest then in the idea of building special lambing sheds, rather like maternity hospitals, where the ewes could lamb safely, regardless of the weather. About this time I attended a field day in Hamilton organised by the Department of Agriculture, at which the subject of lambing sheds came up. I was a fairly young farmer then, but I stood up and said I could see no logic in spending a lot of money on lambing sheds plus the extra labour they involved when ewes could be protected just as well from the weather by a shelter belt of trees, which cost relatively little to establish. I went on to say that four years earlier my small daughter, Amanda, had helped me plant a belt of she-oaks, which were now providing really good shelter. The audience, consisting largely of farmers and department people, was unimpressed. They let me know that in their opinion growing trees to protect stock was impractical.

Which trees make the best shelter belts? Personally, I think drooping she-oaks are hard to beat as shelter-belt trees. They also happen to be indigenous to the Hamilton area, so I admit to being biased in their favour. When someone asked me a while ago which type of tree was my favourite, I replied it was probably the river red gum. But I do have a soft spot for drooping she-oaks, which I consider the signature tree of Lanark. Drooping she-oaks were widespread at the time of white settlement, but most were later wiped out. Early settlers cut them down and fed them to their stock when grass was in short supply. Or people cut them down to fuel bakers ovens. Even when the she-oaks regenerated later, they were eaten by rabbits. When I planted a dozen or so on our roadside in the early 1960s I planted each of them in the middle of a wild briar rose bush, whose thorns protected the tree from rabbits and hares.

The drooping she-oak is a superb tree in a number of respects. It is an evergreen, of course, and at Lanark, when fully grown, stands around six metres tall. It is a beautiful, weeping, fast-growing tree. Male trees bear large numbers of small, attractive, orange-brown spikes at the end of the branchlets, while female trees are festooned with large numbers of seed capsules or nuts. I used to call these the ‘Lanark prickly men’ when our grandchildren were small.

The reason she-oaks make such good shelter-belt trees is that they block just enough wind—and let just enough wind through. The latter is as important as the former. Windbreaks must never be impermeable. If instead of a shelter belt of trees you erected, say, a solid, ten-metre-high steel fence to protect your stock, you would generate so much turbulence on the leeward side of the fence that it would be almost as bad for the stock as the wind.

My policy when I began planting she-oaks as shelter for sheep was to plant them as if I were planting an orchard— in rows a few metres apart. I cut a hole in the middle of a superphosphate bag, lay the bag on the ground and planted a tree in the hole, the idea being that the super bag would keep the ground cool and moist, rather like a layer of mulch. I then put a tree guard around each plant, which I made myself from netting, and rotary-hoed around the plants for the first two years to ensure that no other plants were competing with the trees.

The reason I rotary-hoed was that there were no safe sprays on the market then to control weeds. The rotary-hoeing proved very effective. My aim was to keep the ground around each tree completely bare to a radius of 75 centimetres. When safer sprays became available, I used them instead of the rotary hoe. By now, we were planting trees not by the hundreds but by the thousands, so spraying was the only practical option. In areas where there is a dense growth of grass or weeds, the site of each tree should ideally be sprayed in the previous spring—a year before planting—to a radius of 75 centimetres. Do not blanket-spray. It is enough to have the ground around each tree bare to a distance of 75 centimetres. The rest should be left to provide some ground-level shelter and a microclimate of grass and weeds.

If you are not well enough organised to spray in the previous spring, then spray in the following autumn (you must wait until autumn to catch the weeds that germinate then) and spray again immediately before planting in spring. As I explained in an earlier chapter, we used to plant in autumn, as many people in some areas are obliged to do, but we found that the trees we planted then often fared badly. They would just sit in their holes for the whole of the winter, suffering from the frosts and looking sorry for themselves. This is why we switched to planting in spring, preferably late September or early October, when the ground was warming up. Provided we did the required preparation work, the spring plantings proved successful.

The real key to growing trees successfully is to do a follow-up spray the following autumn—that is, about six months after planting. Not many people do this, which is why not many people have trees that grow rapidly. Ideally, you should strive to keep the area immediately around each tree bare to a distance of 75 centimetres for the first eighteen months. If you do this, you should not need to water the tree after you plant it. Whenever I plant trees I always have the tube stock sitting in a bucket of water. If the ground is dry, I may also water each hole just before I put the tree in. After that, though, watering will not be necessary—provided the trees you plant are of a suitable species and provided they do not have to compete for moisture with weeds and grass.

Planted and fostered in this way, the she-oaks we planted at Lanark had close to a 100 per cent survival rate. They grew rapidly, too, generally reaching a height of around 1.5 metres in twelve months. The rapid growth meant that, if the she-oaks were fairly close together (at Lanark we planted them 3.5 metres apart), they would provide sheep with perfectly good shelter in as little as three years.

Drooping she-oaks have another attribute that appeals to me personally: the sound they make when wind blows through their branches. It is a whispering noise, although this description hardly does the sound justice; you have to hear it yourself to appreciate it. The nineteenth-century commentator James Bonwick was obviously impressed by the sound. In his book Western Victoria, its Geography, Geology, and Social Condition: The narrative of an educational tour in 1857, he wrote, ‘Gentle undulating plains spread out before me, clothed with the weird-looking Casuarina or She Oak, through whose knotted, leafless appendages the wind breathes with a soft music like that of the Aeolian harp.’

Drooping she-oaks produce excellent timber. The wood is extremely hard and difficult to work, but it splits readily and was once used extensively for making shingles. The shearers’ quarters at Bassett has a roof clad with casuarina shingles that is still intact. The she-oak’s botanical name, by the way, used to be Casuarina stricta, but a few years ago this was changed to Allocasuarina verticillata.

The mention of the she-oak’s botanical name reminds me of something that happened at a farmers’ meeting at Branxholme some years ago. The guest speaker was a botanist, and during the meeting an elderly farmer got up and said he had a question to ask about establishing stands of Casuarina stricta in certain parts of his property. Instead of just answering the question, the botanist began by pointing out that Casuarina stricta was an obsolete name. The old farmer was made to look foolish. I thought this was intellectual snobbery of the worst kind, and I told the botanist so afterwards. I said, ‘That’s the last time that poor old bastard will ever try to use a botanical name.’

A friend, Dr John French, a CSIRO research scientist, urged me for years to establish a ‘coppice-with-standards’ plantation at Lanark in the traditional European format. He believed plantations of this kind would be a valuable addition to Australian farms generally. A coppice-with-standards plantation typically consists of timber trees (the ‘standards’) that are allowed to grow to full height in scattered formation within a fairly dense woodlot of smaller trees that are coppiced regularly—that is, heavily cut back for firewood or timber. In the spring of 1985, not long after John had visited Lanark, I began to plant just such a woodlot. When established, there were about 50 ‘standard’ trees, consisting of various eucalypts, growing among 1100 drooping she-oaks, which formed the coppice under-storey. We also included a handful of habitat trees, specifically river she-oaks and swamp paperbarks (Melaleuca ericifolia) in a particularly wet area. The entire woodlot occupied an area of not quite three acres. At the time, I could picture myself at some distant date sitting in the copse and listening to soft breezes stir the drooping she-oak branchlets.

In 1985 it was estimated that the standard trees would be harvested in about 60 years. In fact, quite a few of the standards did not survive. Instead, the best-formed of the she-oaks were pruned and allowed to grow to full height.

Windbreaks have one other role to play in the Australian landscape that most farmers seem unaware of: they can retard bushfires. How do they do this? Simply by reducing wind strength. An effective windbreak of trees will greatly slow the spread of fire downwind of it. I say ‘greatly’ because a reduction in wind strength always slows a fire exponentially. By that I mean that if a wind fanning a fire has its strength reduced by, say, 50 per cent, the speed of the fire’s spread will be reduced by more than 50 per cent and probably by as much as two-thirds.