The world in my garden - part I

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A garden is a tiny representation of the environment in which we live. It will share many of the same noises, soils, air, birds and climate that we find if we walk down the road. Yet as the garden matures it will come to ressemble the others in the street a little less and the personality of the people who tend it a little more, untill two gardens side by side can look as if they should be found in different continents.
It is this bringing together of the wild and untameable, with the intrinsically personal and dainty that make so many gardens endlessly alluring.
So over the next few notes I want to explore some of these contradictions by taking a ramble through my garden.
I make no excuse for using my own as if it were a blue print for others. It is after all the one that greets me when I wake up, the one that I can reach out to touch and smell rather than just looking at, and the one that is growing with me, allowing me to explore my own attitudes by seeing the consequence of the decisions I make. Perhaps just as importantly there are people around me who remember the houses being built and moving in in 1960 and can help me piece together how things have changed.
Let me start then by placing the garden for you. We live in the south of England, just north of the south downs, a system of steep grassy chalk hills that run all the way from Winchester to Eastbourne.
The garden is the width of a fairly average detached house with small garage. Separated from neighbouring gardens on either side by wooden fences It stretches, roughly rectangular, down a hill for about 100ft to a small stream. At the very bottom of the garden is a small strip of woodland which in turn gives way to a children’s park, farmland and ultimately the south downs.
The Trees
The wooded stretch at the bottom of the garden is made up of large quantities of Alders with the odd Willow, Oak, and Hawthorn whilst on our side of the stream and in neighbouring gardens are a number of large Lawson’s cypress a beautiful golden Thuja Plicata, and in pride of place and the bottom of our garden is a magnificent Willow that overshadows them all. All of the trees are huge. With the exception of the Alders (which are stick thin and sway disconcertingly in a storm) there is nothing to suggest to the untrained eye that this is not a scene of quite some age. The truth is very different.
On 15 October 1987 I was enjoying a beer with friends in David’s room in Cambridge. I was just thinking of calling it a night when we were distracted by the sound of a very old and venerable tree outside the window crashing through an old and venerable stone wall (there is a lot of old and venerable in Cambridge) and right across the road. Unsurprisingly we rang the police to let them know but, and this was a surprise, the police’s response was something along the lines of ‘yes they are doing that a lot tonight’.
And they were right. During what came to be known as the great storm of 1987 in Kent, the roof of my family’s conservatory was being picked up by the wind and transported across a field before being dumped. Whilst back in Sussex some of the most famous public gardens – Wakehurst Place, Sheffield Park, Nyman’s gardens – were taking a beating as trees that had survived for centuries were ripped up in their thousands. Most of the trees that were in our tiny patch of woodland were being summarily flattened. In total 15 million trees were blown down.
We were told at the time that this was a storm of rare magnitude – and we wouldn’t see the like of it for another 300 years or so. Then three years later another storm of similar ferocity struck. Is this climate change?
Afterall carbon dioxide gives rise to the greenhouse effect trapping more heat in the earth’s atmosphere. This in turn changes the air pressures as the warmer airs rise and the difference in the air pressure give rise to more wind. The argument seems fairly compelling and certainly the hurricanes that have been ploughing into the East Coast of America with increasing frequency suggest that something is awry.
The experts are however much less convinced. It is one of the odd ironies of life that the UK – one of the countries least affected by climate change so far – has one of the most sophisticated programmes for modelling climate change.
UKCIP, the UK Climate Impact Programme, has spent the last few years trying to identify what the likely climate change will be in different areas of the UK up to the 2080s. I am not sure whether to laugh or cry at the difficulty of this task given the problems the Met Office had predicting the 1987 storm the day before it happened. However, UKCIP believes that it has something credible to say about what will happen over quite small areas of land and has put numbers to a few important climate change variables such as days without frost, hottest temperatures, and average rainfall. Yet despite these successes UKCIP has been very shy of saying what will happen to the wind. We may get a 3-5% increase in average wind speeds by the 2080s but their models are far from conclusive.
Even if we did know what to expect there are a number of other factors that affect how much damage a storm does. The autumn of 1987 had been mild and the trees were still carrying their full complement of leaves. Just as importantly the ground was sodden, enabling trees to be wrenched from the ground comparatively easily. Our poor little wood with a stream through it is practically a marsh in winter: the trees didn’t stand a chance.
So most of the trees at the bottom of the garden now, and in particular the Alders, are known to be no more than 24 years old.
For a few years after the storm you could look straight out of the garden across the fields and up onto the Downs. You could grow vegetables throughout the garden, and as a south facing garden with a bit of a slope it was filled with sunshine throughout the day. All of this seems very peculiar to me when I lie in my hammock swinging beneath the trees and looking out into the mysterious world that there is now of ferns and brambles. It makes the 80s seem a long time ago, when women had large shoulders and mobile phones masqueraded as bricks.
Cypress, Willows and Alders. A wonderful recipe for a quick fix to a wet place. The Lawson’s Cypresses are noticeably raised away from the stream and must put their feet down a couple of feet to get them wet, but hop over the stream, as you can during the summer, and you will find a very different situation. As I mentioned, the other side is a patch of damp peaty marshland, not treacherous perhaps but certainly unpredictable enough to put off all but the most intrepid explorers, and very prone to flooding.
The vast majority of trees cannot cope with constant water-logging. They simply rot. Willows and Alders though thrive, stabilising river banks and – as in our little patch – colonising marshes and turning them into forests. Enough water remains to power our little stream throughout the year, but there is little doubt that the trees have changed our micro-environment beyond recognition.
Their influence is also felt much further afield. Our little stream flows directly off the Downs which harvest an awful lot of the clouds that come our way from the English Channel. One morning at the very start of 2010 we woke to find that the relentlessly wet winter had converted the whole of the wood and most of the park beyond (as well as a smidgen of our garden) into a large lake. Without the trees that water would have sped onwards into the village to flood the high street as it did in 2000. Instead, the thick peaty sponge beneath the trees, and deep channels created wherever roots had died and rotted allowed much of the water to slowly percolate away.
The trees create a very distinctive micro-climate. As I write this, sitting on the steps at the back of the house I am being buffeted gently by a wind that is playing in the trees. The willow in particular looks like a ship on the high seas. I know that if I went round to the front of the house and onto the street I would need a jumper. Yet sitting here I am protected by a gloriously effective wind-break: effective that is untill the next time all the trees blow down around us.
Underneath the trees it is also much, much colder in summer. It is shadier of course, but refrigeration is a big effect too. All fridges work by evaporating liquids, which takes heat from the air. Woodlands – particularly wet woodlands – do this on a massive scale. Even on the hottest summer’s day the temperature in the hammock under the trees is lovely and comfortable. It is much cooler than it would be under a gazebo.
The water vapour that is released from the top of the trees can then be wafted further inland to fall again as rain. In the UK the most important impact on our rainfall is the Atlantic – an easy source of water. For continental countries, the vapour produced by trees is much more important: this is a difficult balance to strike in countries which are short of water. Locally a tree is a water hog. A mature English Oak can take up to 50 gallons of water a day, and others can take five times that. Clearly this is difficult to cope with in arid areas, and is used as a reason for rejecting reforestation projects. But many trees are good at catching their own drink. The giant redwoods, in their native environment, rely on catching the fog that rolls off the sea, and actually help replenish the water table, whilst for many small islands decent tree cover is the only reason that they have any fresh water supply at all.
Wherever the water comes from, most of the water taken up by a tree is evaporated back into the air, rather than being lost out to sea, so wherever there is water to spare trees are an extremely effective way of sending it inland. In rainforests the forest creates the rain just as much as the rain creates the forest, and sadly this means that deforested lands become dry lands.
Back in Sussex, we are in the lucky position that the stream does not seem to run dry even during those odd summers when the weather is fine, but before we leave the subject of climate I would just add that even during the winter the impact of the wet woodland is to modify the temperature. The Alders and Willows lose their leaves, and so no longer act as coolants and as the mists and dews generated by the stream begin to freeze they release warmth back into the air.
This is so effective that I have heard of gardeners who are willing to stand in the garden at night with a misting spray during a late frost just to take the edge off the chill. It is not a prospect which appeals.
I want to tell you a bit about the Alders and Willows next but that is enough for one note methinks!

• 2 Jul, 2011
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