It has been said that there is nothing new under the sun. And, as an example of how true that statement is, here are a couple more to the same effect: those who forget history are doomed to repeat it; this too, shall pass; and the more things change, the more they stay the same. But, when there is real tumult in the world, there always seems to be a feeling that this time is different.
When it comes to the drought currently plaguing the western US, there is a strong temptation to say that this time, it is different. Numerous studies say that California’s current drought will only get worse. Faced with the prospect of dwindling water supplies, there is understandable concern about an increase in the number and intensity of fires, shrinking crop yields, and a lower quality of life. There can be no doubt that this drought is serious, and perhaps it is true that it is California’s worst drought in the last 1,200 years, but this is history on a small scale.
History on the long scale is written not in words, but in genetic code, giving the grapevine a much longer memory than humanity. Many wine grapes evolved in ancient Spain, a region that is no stranger to severe droughts, and vines employed an effective strategy for surviving with minimal water. Grape vines, where soils allow and drought necessitates, grow a deep and extensive root system, often going more than 20 feet down. By digging deep and creating a large surface area for their roots, the vine increases the chances of finding and using soil moisture to survive the drier years.
This deep root system increases the likelihood of finding water, but vines also adjust how they use the water in a drought. At the beginning of every season, after the leaves and shoots have emerged, the vine flowers. Each pollinated flower will then turn into a grape in a process known as “fruit set.” This is a critical time for the vineyard, and, in a mediterranean climate, also tends to occur immediately after most rain for the year has already fallen. In this environment, the vine has a good idea of the amount of water it will be able to pull from the ground. In a drought, with the hot, dry weather, many flowers will fail to bear fruit, resulting in a smaller crop. This failure to pollinate is known in the wine industry as “shatter.” From a survival perspective, the vine is simply making a rational choice. When there is not enough water to ripen a large number grapes, the vine will produce fewer grapes and preserve water for necessary life functions, surviving another year and waiting for better conditions.
When humans began to cultivate the vine, they noticed that struggling vines made more flavorful wines and, early in a drought, vintages tend to be quite excellent. But, as a drought wore on, the vine had depleted the resources necessary to ripen its fruit and would naturally limit it. Not wanting to settle for less wine, but being unable to control the weather, farmers sought a way to alter the natural outcome, and turned to irrigation.
In my next post, we’ll take a look at how irrigation changed the vineyard, and how some California producers are looking to ancient practices to manage the current drought.