Climate change as a matter of fact (Birds/bees/flowers/trees edition: pistachio trees)

Warm Winters Threaten Nut Trees. Can Science Help Them Chill Out?   (NPR, 2/17/2020)

But several times in the last decade, that timing has been out of sync. The male trees haven't bloomed at the same time as females because the winter was too warm.   

Pistachios and many other trees need to experience "chill hours," spending hundreds of hours below 45 degrees. (Another way to measure is with "chill portions," which take a broader range of temperatures into account.) The most common male pistachio variety requires more chill hours than the female trees. 

Without that down time, the trees don't wake up normally in the spring and they bloom late or erratically. That means fewer pistachios — or at harvest time, farmers will find "blanks," shells with no nut inside. 

"Now, with the weather changing, it's becoming more of a challenge to get those chill hours," Battig says.

Other birds/bees/flowers/trees posts:
White truffles production in Italy.  (11/17/2019)
Pecan orchards of New Mexico.  (9/29/2019)
Italy's olive groves.  (3/11/2019)
Insect apocalypse:  Monarch butterfly.  (12/10/2018)
Lebanon's cedar trees.  (7/19/2018)
Wisconsin's plant hardiness zone map.  (11/16/2017)
Georgia peach orchards.  (9/18/2017)
Northeast U.S. pine forests.  (8/29/2017)
California wine country.  (1/11/2017)

Other editions:
Africa
Arctic/Antarctic
Business and finance
Oceans, lakes and rivers
Rising seas
Worldwide

Other Climate Change as a Matter of Fact posts