Many of you will remember the 1987 hurricane and the havoc it brought to gardens. The images of the flattened trees at Kew and other famous gardens still linger in the memory. Fortunately, not only have most been restored, but the opportunity was also taken to plant different varieties. I was reminded of this when browsing through Gilbert White's 'The Natural History of Selborne' recently.
'In the centre of the village..........stood in old times a vast oak..................Long might it have stood, had not the amazing tempest in 1703 overturned it at once, to the infinite regret of the inhabitants, and the vicar (Gilbert White's Grandfather) who bestowed several pounds in setting it in it's place again'. Unfortunately the tree soon died.
There is, of course, a huge store of information about that storm in 1703. One of the most popular is the account by Daniel Defoe. He writes of 'lead roofing on Westminster Cathedral being scrolled up', and Eddystone lighthouse destroyed along with it's occupants. The estimates gave 123 people killed on land and 8,000 offshore; the Royal Navy lost 128 ships and 1700 men. Millions of trees were lost, and 'a towering whirlwind ..........snapping an old oak in its path' was reported at Bessels Leigh.
I w Rainfall Watering: more than a dry suect.
In recent years there has been much debate on the watering problem in the gardening press. A recent article in the RHS Journal provides a useful summary ('Watch Your Water'. The Garden, January 2008). Much of what has been written revolves around either recent personal experience or the detailed discussions about climate change. It occurs to me that if the scientists had not discovered what is going on in the atmosphere, maybe our plans based on recent observation would be quite different. The very dry periods of 2006 have been balanced by the very wet seasons of 2007-2008. Indeed, we all know about what excess rainfall has done in the last year.
Total rainfall varies hugely in different areas of the country. It is difficult to determine trends, and we all know that averages are almost meaningless in the context of long term changes. The result depends on the time scales over which you calculate. If you look at the Met Office data for the period 1766-2000 you will see that it is almost impossible to detect a trend. Most of the current debate therefore has to be based on future predictions. Indeed, there are several models on the Hadley site, most of which seem to suggest that warmer, drier Summers will be followed by warmer, wetter winters, but the average change of total annual precipitation for the UK is very near to zero.
So the debate seems principally to do with saving winter rainfall for the Summer. Now then, how do you do that? Anyone who has installed a single water butt in the garden will soon realise that the whole butt full can be used up in a few days on everything except a very small garden: the capacity simply is of little use for a long dry period. Much better, then, that new large scale reservoirs are built, like the new one near to Abingdon by Thames Water.
'No, no' I hear from the enthusiastic conservators. But surely, this is the only practicable way to solve the problem.? The hose pipe bans we had in 2006 saved about 10% of the normal consumption. Very important given the low levels in the available reservoirs of course, but there was never any hope of replacing the water saved during the ban by small scale garden storage. To have any impact at all, you need large underground tanks, at a cost and space way beyond anything most people can manage. And the use of 'grey' water, if not fundamentally ill conceived, is marginal. It has to be saved (and cooled), stored, used within a short time, and withheld from edible crops. It would be all to easy to use water containing detergents or surfactants. And as for bath water, well, how many people actually bath these days?
It is clear that gardening techniques such as mulching (at the appropriate time, there is no point in mulching dry ground!), digging in organic matter (but it takes huge quantities and many years on clay soils), and the use of sophisticated soil moisture detectors are of value. Over watering is a common problem, and plants do well with much less water than is commonly thought. Sparse watering on the top of a baked soil can often do more harm than good, as the roots are tempted to grow towards the damper surface. In controlled situations like greenhouse beds or hanging baskets, drip irrigation buried underneath the surface where evaporation is minimal can be effective.
Partial root zone irrigation has already become a popular technique in dry areas, see this for example
In the long term though, more and larger reservoirs have to be the real answer if bans are to be avoided.