California farmers have experienced record early harvests,thanks to exceptionally warm weather during the winter, spring and summer as climate change trends advance.

Early harvests are not necessarily a bad thing. But they are among the first visible symptoms of what will probably lead to a dramatic rearrangement of California’s agricultural geography and water-use policies.

Growing regions will probably shift northward, arid regions will become less productive and measures will likely be taken to regulate use of water.

In some cases, the changing weather may be creating benefits for local farmers.

While winter chill hours are required by many temperate fruit trees—such as most stone fruits—to produce large, healthy crops, farmers say the absence of cold this year resulted in a better crop: The fruits were fewer, but bigger.

However, the overall effects of warming on California’s most lucrative fruit crops are likely to be negative ones. The pistachio industry, for one, is starting to suffer.

After the balmy winter and spring of 2014, the state’s pistachio crop was thick with blanks — empty shells that result when erratic temperatures throw male and female trees out of sync during bloom time. 

Gurreet Brar, the UC Extension farm adviser for nut crops in Fresno County, says samplings of pre-harvest 2015 pistachios are showing a high percentage of blanks, as well. Brar says the almond industry may also be facing troubles as winters and springs become warmer.   The almond industry is conducting trials of about 30 new almond varieties and rootstocks that could be used to replace those that lose productivity or otherwise suffer under long-term warming trends.

For now, the effects of warming on many farmers are almost negligible, resulting only in earlier harvest schedules.

The long-term solution to adapting to warming and drought may be more complex and expensive. Breeding new fruit varieties with more tolerance of aridity, pests and other adverse conditions will be important, says Katherine Pope, orchard adviser with the UC Extension program in Woodland.

However, breeding resilience into crops will take a very long time. “It takes at least 10 to 25 years to really have confidence in a new variety,” Pope said. That, she says, is because of the slow growing pace of trees, and the fact that with most fruit tree species it takes several years just to produce the first fruits. 

Source - http://www.freshplaza.com