Frozen and Thawed -- the start of a (hopefully) better year for our tree fruit

March 23, 2012: Extreme heat caused cherry trees to
bloom a full month early, dooming the crop.

In March 26, 2012, I wrote a blog piece titled, Cooked and frozen - the looming disaster for our tree fruit. Due to a ridiculously warm March and the near inevitability that temperatures would return to normal, I could foresee the impact: "Tomorrow evening, the low temperature here is predicted to be 28 degrees. Assuming that prediction -- or another one for later in the week -- is accurate, our cherry crop will be wiped out. We have no rational or affordable defenses against it." Sure enough, a frost on March 27th -- it got down to 27 degrees here -- wiped out the cherry crop.

What a difference this year! Oh, we've had freezes. 10 of the last 11 nights, including three that were colder than that coldest evening last year. But we haven't been outside to run water to the trees. Haven't even looked. Because this year, the trees haven't bloomed. The hollyhocks haven't bloomed. Nor have the forsythia. The crocuses and the snowdrops are still out.

And that's the way I like it.

The local mean temperature during March was 31 degrees Fahrenheit. That is about a half degree below normal, or virtually indistinguishable from the same month in 2008. We had a bumper crop in 2008. By contrast, the mean temperature during March 2012 was 48 degrees. On the first day of spring this year, the high temperature was 27 degrees. Last year, it was 82 degrees.

This chart shows the extreme difference between local temperatures last year (in red) and this year (in light green).

March 31, 2013: Crocus in full bloom -- a "normal" schedule.
The cherry blossoms are still weeks away, we hope.

Of course, friends are going around asking, "when is spring going to get here?," as if what happened last year should be the norm. But March's high temperature of 57 degrees is entirely normal. Nor is there any guarantee for the crops: while March was kind, we still remember 2002, when a hot spell in mid-April caused the trees to bloom early and led to the crops being wiped out during a cold spell later that month.

One thing to remember about warming trends is that they do not mean that every day or every month will be warmer than last year's. As explained at a page on the NASA web site:

Scientists emphasize that weather patterns cause fluctuations in average temperatures from year to year, but the continued increase in greenhouse gas levels in the atmosphere assures that there will be a long-term rise in global temperatures. Each individual year will not necessarily be warmer than the previous year, but scientists expect each decade to be warmer than the previous decade.

But, despite the hit our heating bill will no doubt take due to the colder temperatures in 2013, I'm glad that this year's fluctuation is downward. Cherry picking to commence in June, if things hold.