Maybe we have more luck next year.

Wishing a great upcoming season…

You’ve got it. The problem is that crop almost always weighs between 5 and 10 times the pruning weight (dead plant matter) at the end of the season. Which means that almost all wine, both good and bad, has a ratio of 5:1 to 10:1 fruit to cane.

It’s not a very helpful metric.

Thanks for the kind words and the comment Rama!

.brian

As for the AQUA observations, I think that biologist is at least slightly misrepresenting the truth. A lot of people have used some theoretical ideas to say that relative humidity should stay about constant in a changing climate, and at least one paper (from 2004) said this wasn’t quite true, that relative humidity was dropping slightly. Exactly what this means is not clear, but I think this is a relatively small point in our overall understanding of climate change. It could help us improve projections of future climate, but it definitely is not saying that previous projections are completely wrong.

Hope that helps!

.brian

Thanks for the comments and I appreciate your insight.

No need to fear, I certainly don’t doubt that there has been warming over the long run. My point was simply that the gaps in our knowledge are pretty large when it comes to systems as complicated as climate and plant biology.

Since you are a climate scientist, I’m curious: How much faith do you put in the climate models? Is the biologist right about the Aqua satellite data or is she misrepresenting?

I’ve started poking around realclimate.org. It’s a little dense for us folks that aren’t steeped in the various controversies they are weighing in on, but it looks interesting.

Thanks again!

I just wanted to make sure you aren’t buying into those points about global warming. I won’t comment on how global warming will affect wine, that will vary by region, soil, agricultural practices, etc. BUT as far as global warming goes, there is overwhelming evidence that there is a LONG TERM TREND toward warming, driven primarily by humans burning fossil fuels and changing the chemical composition of the atmosphere. Yes 1998 was a very hot year, maybe the hottest of the past century, but 2005 was just as warm (maybe a tiny bit cooler, or a tiny bit warmer, there’s disagreement). The idea that the temperatures have “plateaued” is wrong, based on the empirical, observed temperatures. There are bumps along the way, but the long term trend is clear, statistically and physically significant, and has been strongly tied to human influences.

For further evidence, go take a look at some of the info posted at realclimate.org, where climate scientists (rather than biologists, who do not study climate) post explanations for some of the common misconceptions about climate change. I’m not associated with that site, but I am a climate scientist, for what it’s worth.

Since I’m taking viticulture at Napa Valley College this semester, and we recently talked about the use of vine balance being cluster weight as a ratio with pruned wood, even Dr. Steve Krebs there seemed to imply that it was an effective way to balance vine capacity (of crop), meaning avoiding under- or overcropping. There was no mention of quality of crop.

He also made it sound like it was remarkably unreasonable to conduct the vine balance experiment in a working vineyard, because you couldn’t do more than a sampling of vines (you wouldn’t do it to an entire vineyard, because each vine has it’s own balanced form — some vines are stronger than others and can carry more crop). When we did a pruning field study at the NVC vineyard, we used shoot vigor (being that a balanced vine would have 1 year wood between 4-5 feet in length) as a measure of whether the vine was in balance or not, which dictated how we pruned the vine for this year’s harvest. These were cane-pruned Cab Sauv vines. This is how I see pruning crews working in the field. Having a pruning crew recording pruned wood weight on a per-vine basis, is this really being done? I guess I don’t see how you could practice that kind of “vine balance” in a practical way.

And since we’re in the same boat (8.6 acres planted, and our dry-farmed vineyard yielded less tonnage per acres than YOUR vineyard), I thought it interesting that we’re confronted with the same concerns about how to balance fruit (and ostensibly, wine) quality with being able to stay in business as a grower.

But here’s the Q factor in all of this: You can attempt to work backward from wine quality, but no matter how consistent your viticultural practices, the growing season itself can throw a huge monkey wrench in the works. 2007 is a fine example of that, since tonnages were generally down up to 30% all over the county.

What I think I am saying when I say “know your vineyard” is that you have to make wine using the fruit and then gently and gradually adjust your practices (with exceptions, naturally) to move toward what you think will be a better outcome. This I think is the same thing that Greg is saying in his comment.

Excellent discussion, I love going deep on viticulture sometimes, it’s a good review, considering my midterm for vit is next week!