Climate Change | Fall 2019


Change

When the first murmurs of global warming began to surface decades ago, my reaction was that this could be a good thing for Linden as our Cabernet Sauvignon struggled to ripen and a bit more heat would help. However, I was not aware of the associated weather extremes of a warming atmosphere.

Climate is what you plan for, weather is what you get. If the climate changes, then the planning also needs to change. Along these lines, I’ve been evaluating three aspects of our viticultural management.

Canopy Management

Increasingly frequent and more intense extreme thunderstorms during the growing season have forced me to rethink some aspects of canopy management. We experienced two hail events this June. One was minor with little damage and one was moderate with significant berry bruising. Those blocks that were already leaf pulled suffered the most damage. In the future we will be doing only a very light leaf removal of lower leaves and will be leaving a denser canopy (even some laterals) just above the fruit zone. My last visit to Barolo saw about 10% of the vineyards with hail netting. I hope it doesn’t come to that.

Severe winds during storms down more shoots, just after shoot positioning. We will be installing additional catch wires this winter to help mitigate this annoying problem.

Increased rainfall results in more vigor. I finally surrendered and will purchase a mechanical hedger as we are now having trouble keeping up with the task by hand.

New Plantings

Another unfortunate consequence of climate change is increased problems in vineyard establishment. I’ve had to redefine the concept of winter damage. In the 1980s and 1990s our concern was bud mortality. Now it is vine mortality. Decades ago we would regularly experience temperatures below zero F. Hardscrabble hit -13F in 1994. There was significant yield loss, but the vines survived.

Young vines are having trouble making it to adulthood. Wildly fluctuating winter temperatures (2014) result in more vascular damage including but not limited to Crown Gall. Dismal growing seasons (2018) inhibit hardening off, sending weak vines into the winter. Many of our young vines died in the winter of 2019. The problems are exclusive to young vines (this includes replants). As the vines get older the problem diminishes. By year eight we rarely see a problem.

I stopped hilling up in the late 1980’s. While I would reconsider this method for young vines, my vineyard layout no longer allows me to do this: very tight row spacing (2m), established under row cover crops, and steep slopes with rows oriented up and down. I’m looking for alternatives and open to suggestions.

Climate Change Trial Vineyard

Our European colleagues have started to come to terms with the negative effects of climate change. Varieties that have performed well for centuries on their terroir are now being pushed out of their ripening sweet spot. Even conservative Bordeaux recently authorized the planting of several varieties that would have been considered scandalous a decade or two ago.

We in Virginia are still very much trying to get a handle on our own identity. We’ve based our industry on a handful of grape varieties that have served us well, but there is a big world out there and we too need to be more active in exploring other options. This will take a lot of time.

Next year, at Hardscrabble we will start planting a trial vineyard with cultivars that we hope will perform well under a less benign climate. We will only be planting about a dozen vines of each variety. The idea at this stage is to only evaluate vineyard performance. In another ten years, if a certain variety does well, then we may consider a larger planting, with enough yield to make wine.

We are looking primarily for three attributes:

  1. Late ripening: avoiding ripening under hot humid conditions where wine quality suffers.

  2. Bunch rot resistance. Thick skins and loose clusters is the mantra here.

  3. Cold hardiness. There is not much guidance here as most European varieties originate in milder climates. We can only plant and wait for some brutal winters, which is the whole idea of an experimental vineyard.


Grape Press, Fall 2019


Jim Law