June 2011 Douro Insider

June turned out to be rather a strange month, surprising both in its extreme temperatures over one devastating weekend, and in its unseasonable coolness during the rest of the month.  After an abnormally hot May (which registered a mean temperature three degrees above average in Pinhão) it was hardly unexpected when things cooled down considerably as the new month got underway.  And although it was initially dry and sunny, it stayed remarkably fresh by the standards of this time of the year, at least for the first three weeks.  Furthermore, it felt much less oppressive than a usual June because of some quite windy days which were generally welcomed as they helped to bring about a reduction in the overall humidity.  The morning dews that had caused us problems with fungal diseases accordingly came to an end as a fortuitous consequence.

About a week in it clouded over briefly and, even though it still felt quite sticky at times on the coast, there were days in the Douro on which the maximum temperature barely reached the mid-20ºs C.  As the days got longer the nights seemed to get cooler (and windier) with temperatures sometimes even dropping below 10º.  The weather was still unsure of itself getting towards mid-month, with some ongoing sporadic cloudiness and occasional spots of rain.  The humidity returned in the third week just to make sure that the conscientious viticulturist didn’t stop worrying about powdery mildew.

But if the first 20-odd days of the month seemed innocuous enough, they were not.  A sudden and violent hailstorm hit the Vilariça region (in the northeast of the Douro) on 5th and smashed into the vineyards, shredding leaves and damaging the bunches.  By and large, the injured berries eventually dried out and dropped off without rotting so there are no negative implications for the quality of the fruit; on the contrary, an optimist might consider it to have been an opportune monda verde (or green harvest) which loosened up the bunches.  In due time the foliage will recover with new growth, but even if the remaining berries compensate to a certain degree, there has been reduction in the potential crop as a result of this storm.

What happened over the calamitous last weekend of the month, however, will ensure that the S.  João celebrations of 2011 will live long and infamously in the collective memory of Douro viticulture.  Whilst we enjoyed a well-deserved long weekend (with two perfectly synchronised public holidays on a Thursday and Friday) something remarkable happened to the weather.  For two or three days the temperatures suddenly rocketed into the low 40ºs with matching extreme ultra-violet levels.  For those more familiar with Fahrenheit, temperatures in excess of 106º were recorded in the (again unfortunate) Vilariça valley.  The vines were completely unprepared for this thermal onslaught, and it inflicted widespread and very intense sunburn on the fruit, leading to the complete abortion, followed by immediate desiccation, of many of the bunches in the space of a weekend.

This hideous pattern was repeated across the region, but with obviously exacerbated effects in the hotter Douro Superior.  Almost without exception the damage was restricted to the Tinta Barroca, and principally in vineyards with a south-westerly exposition which bore the brunt of the afternoon sun.  Parcelas (vineyard plots) which managed to unite the unhappy conjunction of variety, sub-region and exposition lost the entire crop; elsewhere more vulnerable berries were killed off leaving the rest of the bunch intact.  Not even the oldest caseiros can remember having seen sunburn quite like it.

Why should the Barroca have suffered in particular, though? Probably it was down to a combination of factors: firstly the bunches tend to be longer than the other varieties, meaning that the bottom part at least is already more exposed.  Secondly, it produces grapes famous for being thin-skinned (hence their tendency to dehydrate and therefore produce musts with very high sugar levels).  And finally, it is one of the first castas (varieties) to reach veraison, meaning that the sensitive skins of the berries were already starting to soften when the heat struck.  It was not entirely alone in the face of these tribulations, however.  Word on the Douro grapevine soon came in from across the region with sad reports of considerable damage in the Souzão too (another thin-skinned variety) and even in the normally flame-proof Touriga Francesa.  If there is a positive side to be found, the good news is that none of this year’s three big problems (hail, sunburn and downy mildew – see last month’s report) will affect the quality of the fruit since the berries in question simply never make it into the crusher.  Yields will be down across the region, nevertheless, but a positive reading of the situation might even find that fact to be encouraging.

The balance of the month showed us that one weekend of extreme heat was not enough to stop it being coolest June since 1997, in spite of five days with a maximum over 35º in Pinhão.  There the average temperature in June was exactly the same as that of May, coming in at 20.5º (compared with a long-term mean of 21.7º).  Rainfall was only half as much, however, at 8 mm, which is less than a quarter of the average (33 mm).  Records from across the Douro showed surprisingly little variation between quintas this month, in contrast with May’s heterogeneity, although the same could not be said on a national level.  Oddly enough there was a clear north-south divide across Portugal as a whole which is quite improbable in such a small country.  The north was often much cooler than the south, and very unusually Faro was frequently the hottest place in the country, with temperatures into mid-30ºs whilst elsewhere it stayed resolutely in the 20s.

The precipitation situation was not particularly inspiring either.  The usual graph shows that our initial water deficit has been gradually increasing due to six consecutive drier than average months.  More worryingly, 10 months out of the last 12 have produced sub-mean rainfall.  Our current total for this year stands at just 234 mm which certainly does appear to be well below the 355 mm that might have been expected.  On the other hand, looking back to the last three months of last year (which contributed nearly 400 mm of rainfall) it is clear that the soil water level was well replenished at the time and we do not yet have cause for concern.  Frustratingly, for the pitiful amount of rain we have had during the spring, controlling the fungal diseases has been particularly challenging so far.  Fortunately the worst should now be over.

Perhaps the only reason that more phytosanitary treatments have not been applied so far is that the vegetative cycle this year is so advanced that there simply hasn’t been time to get round the vineyards more often.  By the time veraison comes, the risk posed by mildews is virtually nil, and by the end of June this time was fast approaching, with some scattered berries already coloured.  The canes were also maturing remarkably early with many lignified by mid-month, and the rampant shoot growth was finally starting to slow down.  This only really happens when the vines begin to feel the onset of water stress and that seemingly was not the case until the very end of the month.

Accordingly June was yet again a time when canopy management was a major worry.  Despampa (shoot thinning) and empara (shoot positioning) featured particularly heavily once more and were again followed up by despontas (hedging) in the less developed vineyards.  As before, there were other plants to worry about in addition to the vines, and so weed control and grass cutting were also prominent activities, as well as the occasional ploughing.  Hopefully there will not be much more of this required from now on but some further activity will doubtless crop up in July.  Insecticides and fungicides also put in an appearance again as we had to ensure the good health of the grapes that had hitherto survived the tribulations of a difficult growing season.  This hardier fruit is fortunately still in excellent condition, and hopes remain high for a harvest of exceptional quality.

As ever, this year’s new plantations require special attention.  With only a few months of root growth since the bench grafts were stuck in the ground around March, they clearly do not have the resources to extract water from very deep in the earth and must be irrigated by hand and hosepipe.  Caldeiras (watering depressions) that should be able to hold in excess of 15 litres of water are dug manually for each little vine and are dutifully filled when our new charges start to look thirsty.  In spite of the dry spring we are hoping that only three passes will be required this year.  The first, towards the end of June, will be followed by another in mid-July, and again in early August should the summer progress normally.  Then, some time before September, any welcome thunderstorm will see them through until the first of the autumn rains.

Incidentally, the take rate appears to be excellent so far, with the percentage of sprouting vines comfortably into the high 90s.  If they last the next three months, which everything indicates they should, then they will be on their own, and we would expect them to survive all but the most brutally hot and dry second summer without any additional water.  As was mentioned last month, stone clearing is also a priority to enable the smooth passage of agricultural machinery through these young vineyards, and of course that of the watering team.  Fortunately the sparse vegetation on these young vines means that the leaves are kept exceptionally well-aerated, and fungal problems in the first couple of years are virtually unheard of in the Douro.  The fact that they have no fruit yet also means that there are no bunches to require protection.

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