On Imposing a Grid on the Wind

In Muizenberg where I live, the wind patterns are all-important to comfortable existence. There are two prevailing winds, the South-Easter, which blows throughout the summer months and the North-Wester, which brings intermittent rain, mostly in winter. This means that our lucky suburb misses most of the air-borne pollution that our city generates. 

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 The winter winds come in from the South Atlantic, over Hout Bay, rises at Chapman’s Peak, passes over Silvermine and Steenberg, and then down the face of the Muizenberg itself. The Summer wind comes from the warmer Indian Ocean side, crosses False Bay, and hits us directly. Either way, there’s not much industrial development upwind, which means that we enjoy the benefit of urban living with fresh air on all but the stillest days.

The South-Easter is unrelenting in the summer, blowing at 20 – 40kph for months on end, and in times of extra turbulence, three or four times a year, bringing with it salt in a fine aerosol mist of seawater that penetrates a kilometre or more inland. The salt is lethal to plants not adapted to shoreline living, burning the leaves and flowers, and the vigilant gardener has to spray the leaves with fresh water to wash it off.

In the last century or so, people have imposed into this flow of wind a series of square and rectangular structures, the houses and businesses that fill the area from where the mountain levels out enough to build on, down to the shore. The violent meeting of the South-Easter with these hard-edged shapes creates turbulences which can be violent and unexpected, and speeds up air-flow in areas where it squeezes larger volumes between narrow gaps. I have watched this meeting of wind and house with astonishment for the 13 or so years we have been here.

One response was to write a sonnet cycle about it, A Movement of Air. But a more practical response has been living with trees.

Our house faces north, and the small front garden is a green bubble. The trees grow in the lee of the house to the level of the roof, but the wind burns off any shoots that grow too high, creating a kind of wind-tunnel topiary. The area under this canopy is effectively shielded from all but the gustiest wind, so that we can enjoy a candle-lit evening our front stoep, even when the South-Easter is blowing.

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 And all of it achieved by doing nothing. There were two avocado-pear trees, a loquat and an ornamental pomegranate growing in the front when we arrived. To these we added a Cussonia. We resisted the new owner’s urge to “let in light” and let the trees be, even though we favoured indigenous plants. The back garden was a disaster. Here the house rises a full three narrow stories, facing bang into the wind. The previous owner had uprooted the mature palm trees that had sheltered the yard and sold them to Century City. There were a couple of straggly “fast-growing” cyprus trees and a line of four Syzygium, a species of Australian myrtle against the south fence, struggling against the wind that is channelled between two houses. The yard was sandy and bleak and there was a pool. We left the existing trees and added an olive – the only tree to really thrive, this year we’ll be picking several kilos of fruit. In the face of restrictions we planted a garden that hardly needed water, a small lawn for the children to play on, and a vegetable patch.

 Thirteen years later, the one cypress is half dead, the other still growing but bent by the wind into the gap between our house and the eastern neighbour.

The Syzygiums had grown to perhaps 5 or 6 metres tall, and were starting to form a serious wind deflector, moving air upward from the back fence towards the roofs rather than through the yard. They’re the trees to the right of the picture, and in the background in the picture on the right, and formed a dense barrier to wind.

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But the neighbour on the south wanted to build. And there’s the rub.

 What he wanted to build was a garage in which he could park his large Merc as well as his wife’s smaller car. The garage would come right to the boundary, and be over three metres high. He showed us plans. We agreed, since “good fences make good neighbours.” It took them about two years to get around building, and then it began.

 The neighbour is a decent guy but very punctilious. He had the plot surveyed and discovered that the old fence is in some places about 7cm (a hand-width) over on his side. Everything had to be moved, including a pool-pump (at some expense.) When it came to the trees, we agreed that one had to go, since the law, like the tree, was arguably on his side.

But the builders had other ideas, and two trees were cut, leaving a gap in the wind-tunnel. Bushes were destroyed. Later I found the poor neighbour standing on top of his newly erected wall, sawing off any branches that crossed the imaginary plane of the boundary. The wind-break is no more.

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It was like watching someone sawing off the branch he’s sitting on. He will never be able to use the “deck” which is supposed to go on top of the garage, since it is built in a space that is a wind-tunnel throughout the summer months. The trees won’t grow into the gap because their shoots will be burned off.

The problem is really the turbulence generated when we impose a rectilinear grid on the rather more free-flowing natural world. The natural world does not of course care about the straight lines we draw on it to designate “property”. The trees grow over the fence, the wind flows around everything. The trees embody a living adaptation to their natural conditions. By cutting through them along an imaginary plane dictated by property and the law, their 20-year long aerodynamic adaptation has been destroyed, and neither neighbour will be able to enjoy its benefits again. The law offers us no guidance here – it is itself a part of the grid.

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