January 2010 Douro Insider

As is well-known, the Atlantic Ocean is the predominant force influencing Western Europe’s weather.  The jet stream that comes in over the sea normally passes north of Iberia, but in late December it moved southwards into the Mediterranean, bringing unsettled weather and an awful lot of rain over Christmas and the New Year.  This meant that 2010 got off to a very wet start indeed.  But towards the end of the first week of the year came a reversal of the usual weather patterns due to an area of low pressure over Açores and high pressure over UK and the polar region.  This large high pushed cold air from the Arctic southwards, not only over Europe but also over parts of Asia and North America.  Technically it is termed a ‘negative arctic oscillation’, and this one lasted much longer than usual so the effects were magnified.  Its manifestation here was icy cold and clear conditions for several days.  It is interesting to note that a single weather system had such widespread effects that it was responsible not only for the cold in Northern Portugal but also for heavy snow in China, India and America.

Accordingly, the second weekend of the month was extremely cold with snowflakes even being spotted in Porto which is very unusual.  And in the Douro it settled heavily right down to the level of the river again.  Indeed, at several quintas a day of work was lost on the 11th due to heavy covering of snow.  This freezing spell was almost immediately brought to a halt by a reversal of the prevailing wind direction and once again the more usual Southwesterly winds blew in off the sea, bringing with them a mass of cold and wet air.  Predictably that meant yet more intense and sustained rainfall.  Frustratingly, the rain caused even more damage in the vineyards and for much of the week conditions were so bad that the agricultural workers did not even attempt to work in the quintas.  Just upstream from Tua the sodden earth on the banks of the Douro eventually gave way, creating a landslide onto the railway line which caused its collapse into the river.  It was extremely windy too, and just thoroughly unpleasant all round.

Towards the end of the third week it turned a little warmer and a little less wet but the skies still remained pretty grey.  Finally, on the penultimate weekend, the sun came out a bit for the first time in ages, and we then enjoyed clear skies until the end of the month.  It seemed as though the worst might at last be over.  The loss of the cloud blanket made the days pleasant, but of course meant that temperatures dropped considerably at night and thus it marked a return to the mornings of frosts and frozen puddles.  There was predictably an increasing disparity between day and night time temperatures, and surprisingly high winds blew up which also started to dry out the waterlogged earth.

In Pinhão the monthly average temperature of 8.1º C was a little higher than the long-term value of 7.9º.  This data confirms that the Douro did in fact experience its sixth consecutive month of above average temperatures, doubtlessly due to the slightly warming effect of overcast skies and incessant rain.  In all there were only three nights of (slightly) sub-zero temperatures.

Pinhão suffered 15 consecutive rainy days in the middle of the month and as a result it was also the fourth consecutive month of above-average precipitation, with 128 mm comfortably more that the 90 mm that might have been expected.  Otherwise the month was of little interest: a typical January if a little wetter than normal.  The graph below charting our water status for the current year therefore shows a slight cushion after the first month.  In conjunction with the autumnal precipitation at least this positive note goes some way towards mitigating all the damage the vineyards have sustained.

Life in the vineyards in January is never pleasant and, as has already been mentioned, there were several working days lost because the weather was simply too bad to go outdoors.  The rest of the time, almost without exception, we plodded on with the pruning and cane shredding this month.  In general, by the end of January, most quintas were very close indeed to finishing, if they hadn’t already.  The latter stages of pruning may differ slightly as normally we leave the newest vineyards until the end.  This means that the vines will need to be trained as well as pruned and the whole process is somewhat more time-consuming.  Similarly, the vinhas velhas (which are often cane-pruned) need to be revisited at about this time so that the canes prepared by pruning can be arched and tied down onto the fruiting wire.  Cane collection, for grafting, is also carried out.

In terms of both man-hours and expense, pruning and harvesting are by far the two largest operations of the viticultural year, with approximately equal weight.  The main difference is, of course, that the window for pruning is much wider than that for time-critical harvesting.  So whilst harvesting is carried out relatively quickly with the additional assistance of dozens of temporary workers, pruning is tackled with only our regular workforce over a much longer period of time.  By the time they get to the end of it, the relief at finally being able to do something different is clear.

At the majority of the quintas the next step was to start on the trellis maintenance which must, of course, be carried whilst the vines are still dormant.  This involves replacing any broken trellis posts (or stones) which might have been damaged during the course of the year, often due to contact with the prepruner.  Missing staples are replaced, broken wires mended, and the wires are then re-tensioned.  It should be noted that at this stage the soil is so waterlogged that it would be unwise to tighten the wires too much – all this would do is shift the end assemblies out of line in the mud or even pull over posts.  In all likelihood many of the strainers will have to be retightened in the summer when the soil has set.

A number of properties took advantage of this relative lull to begin re-trellising some old parcels that it had been decided to regenerate rather than completely replant.  Whilst nowadays we would expect the trellis to last as long as the vineyard, in some of the older blocks the vines have outlasted the posts and wires.  This is particularly the case where brittle schist posts had been installed originally, perhaps not anticipating the degree of mechanisation that we now have.  Removing the old trellis and replacing it with a modern one can give the vineyard a new lease of life.  The stone posts are replaced by more resilient wooden ones, the old and rusty wires exchanged for galvanised ones and often the height of the structure is increased too.  Double foliage wires will normally be put in (in place of single ones) and the decision may be taken to use moveable wires (with different positions) or at least open staples to facilitate tucking in the shoots.

Normally we take advantage of this operation to retrain the vines too, as more often than not the cordons are rather irregular and it is likely that the height of the fruiting wire will need be raised by a few centimetres in any case.  Choosing a strong and well-positioned cane to retrain, the rest of the old cordon (by now often quite decrepit) is removed and the new cane trained onto the wire to form the basis of a unilateral cordon.  There will be some reduction in yield the first year, but by the second year the vines will be stronger than ever.  Clearly this operation must be carried out before budburst so as to avoid damaging the new shoots.

Other quintas were still carrying out fertilisations or localised soil corrections that hadn’t been completed in the autumn.  Where this is done manually caldeiras (hollows) must be dug at the base of each vine into which the fertiliser is dropped before covering it up.  Alternatively, a furrow close to the row of vines can be opened up using the scarifier (with some of the teeth temporarily removed) into which the fertiliser can be poured.

In terms of damage repairs, terraces cannot be rebuilt for several weeks (or even months) until the earth is much drier.  Collapsed walls, on the other hand, can be reconstructed immediately and accordingly this was a job ongoing at a large number of properties.  Repairs to the tracks should also be carried out as soon as possible, not only because they need to be transitable to allow access to the vineyards but also because rutted tracks have a tendency of getting much worse if not evened out immediately.  Also, given that many of the tracks in the Douro drain water out of the vineyards, any interruption to the run-off means that damage elsewhere (i.e.  in the vineyards themselves) becomes a likelihood.

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