December 2009 Douro Insider

Conditions at the very start of the month were what we in the business would describe as ‘bloody awful’. The first of the month, a public holiday, was a complete washout in the city, and sure enough the next day the rain reached the vineyards. Very often the weather in Porto takes somewhere between 12 and 24 hours to move inland to the Douro. There was reasonable rain for the first week which was good for the soil water levels even if not conducive to happy pruning. It seemed pretty cold too, although that turned out to be nothing compared with what was to come in the middle of the month.

Just as the UK suddenly disappeared under a heavy blanket of snow brought on by an anticyclone hovering over the British Isles, the same weather system dragged a mass of cold air southwards to Iberia. For about a week from the 13th it turned very cold indeed, staying clear, with some localised frosts even falling in Porto and Gaia. It was colder still in the Douro but the humidity was low and frosts didn’t always form as heavily as they might have in spite of the freezing temperatures. What few puddles there were on the north-facing slopes were still frozen well into the afternoon. This bitter spell shook off the very last leaves from any vines that hadn’t already been pruned, and we also lost some olives to the frost.

On the 16th we had a single day of snowfalls across much of the country. There was plenty of it up in Vila Real but it decreased in depth moving down onto the lower ground, and only a smattering settled at most of the quintas at river level. After the cold came more of the wet, and we were hit by some really quite awful weather that went on for the rest of the year. There were bad storms in Porto just before Christmas bringing hail, localised flooding and lots of debris on the roads. The festive season itself was miserably cold and wet, but a real optimist might accurately claim that there was a very slight warming for the last couple of days of the year. On the other hand, it was brought on by more torrential rain, thunderstorms, power cuts and a general apocalyptic sort of feel to the weather. There was more flooding in the vineyards, roads were running with torrents of water and the river finally began to rise up its banks again after so long. New Year was one to spend indoors, well stocked up on firewood and port.

Based on what has already been said, the specific details will come as no surprise. When compared with the long-term mean, Pinhão was absolutely spot-on the average temperature for December (8.6º C) in spite of suffering four nights below freezing. The absolute maximum and minimum values were 18.7º and -2.1 respectively, which appears unremarkable for this time of the year. Rain, after all, tends to stabilise temperatures. It was, however, two and a half times wetter than would have been expected and it rained on 19 days this month. That means that our usual precipitation graph below has finally broken even after so long in negative territory due to the huge total of 215 mm of precipitation, almost all of it coming in the second half of the month. It eventually turned out to be the wettest month since January 2003. Bear in mind that the average for December is a more reasonable 85 mm.

Taking stock at the end of the calendar year did reveal some interesting facts, of which the sharp upturn in precipitation during the last quarter was particularly significant. The cumulative total, in constant deficit since March, did in fact eventually exceed the mean annual value (but not until the 28th December!) The total figure in Pinhão for 2009 was 725 mm, just a fraction over the mean of 675 mm. What this statistic does not tell us is that a remarkable 61% of this year’s rainfall actually fell after the vintage had finished. So, whilst we were not technically short-changed in the end, it clearly rained at the wrong time and as a result the vines suffered somewhat in the period immediately leading up to the harvest. The heavily skewed distribution of rainfall towards the end of the year is clearly visible in the graph. In the end five months were actually wetter than average in 2009.

The other graph, showing monthly temperatures, reveals that the year eventually gave us eight months out of the twelve with above average values. There were some more or less random fluctuations relative to the mean early in the season but then a consistently warmer period starts in August and goes on through the autumn until the end of the year. This second-half rally is enough to ensure that the year ends up with an above average mean temperature, at 16.4º. This is half a degree above the long-term value, which stands at 15.9º.

December is usually a relatively quiet month in terms of overall activity given that there are inevitably a number of working days lost over the festive season. Couple that with two public holidays which in this instance both fell on Tuesdays, inviting the obvious long weekends, and it is clearly a month in which it is not possible to plan vast viticultural projects. In practice, therefore, virtually nothing new was begun, but rather November’s jobs were carried on as best as was possible between the interruptions. The incessant rain was no help either, and some days in the field were inevitably lost to bad weather. Pruning continued as usual and was almost certainly the task to which most man-hours were dedicated. As would be expected, it is usually preceded by mechanical or even manual prepruning, and followed by cane destruction. By the end of the year most properties were more than half pruned, although usually the newer plantings are left until the end. These vineyards are relatively slower to prune as the vines need to be trained at the same time.

Unfortunately most of the other activities going on were largely bad weather related: the price that we have paid for the end of the drought is more devastation in the vineyards. As was mentioned last month, much of the damage from October’s storm recurred in the same spots as before and part of the problem was that where the taludes had been rebuilt the earth never really had the chance to dry out properly and stabilise itself. December’s rain led to yet more collapsed patamares, as there had been in November. Damage to the tracks caused by torrential run-off also needed to be patched up to make them passable once again, and yet more stone walls came down in the older vineyards, as is so often the case during a wet winter.

Where time permitted one or two properties still had fertilisations to carry out. One of the advantages of all this water is that it will at least ensure that the granules are well dissolved and the nutrients plentifully available to the vines by the time they are required when the spring eventually comes round again. And even though by now it is far too late to hope for any effect before the worst of the winter, there were still places where cover crops were being sown to protect the surface of the soil. They won’t germinate until the soil warms up but by early summer they will have caught up with last year’s self-seeded cultures.

Olive picking has always been a December stalwart but the economic advantages are not particularly clear-cut nowadays. Nevertheless, many quintas were still picking olives this month, but anything not collected by the Christmas ended up on the ground due to the bad weather. The only other activity of note relates to the new plantations planned for 2010. One thing that can be done in the rain is ripping up the old vineyards that are destined to be replanted, if this hasn’t already been done. The posts and wires are removed and the old vines are burned. This needs to be undertaken before the heavy machinery arrives, but under these waterlogged conditions the bulldozers were in no position to start trying to move mud around in any case. If things continue like this there will be delays but at least there is plenty of water in the soil to sustain the rootlings even if planting does have to be carried out late.

Share this post

Leave a Reply

Your email address will not be published. Required fields are marked *