My presumption is that even with last winter in Oregon, west of the Cascades, as warm as it was, we nonetheless came nowhere near running into lack of chill hours as a problem. Would I be correct in that assumption? Can anyone give me an example of what a winter would look like in order to begin running into such a challenge? I note some varieties of fruit require vastly more chilling hours than others? Is this an issue? Where in the West does lack of chill hours begin becoming an issue?
Kind regards,
n

...in southern California for certain fruits. The Pacific Northwest as a region has the highest chill hours in the country because the 32 to 45 degree range is very common. I believe it is in excess of 2,000 hours--there are many chill hour calculators on the Internet.
The winter of 1976/77 was extremely mild from a freezing standpoint, but there were still plenty of 32-45 degree hours.
Nick, I am in Vancouver WA which probably has a little more chill hour than Western OR, depending on where you are, but similar to Portland. Based on spring bloom, I have never had an issue with chill hours, in 15 years, for any fruit tree.
A bigger problem is late frost. Peaches, apricots, and apriums bloom in the mild late winter, then the flowers get frosted. That almost always kills my apricot trees. Plums and cherries worry me each spring, but it doesn't seem to be an issue so far.

Sensitive plants like pie cherries and American persimmons, which you can't grow in So Cal, needed like 1/3 of the chill hours we provide. In the PNW, we list hardiness degrees when people buy plants. In Cal, they list chill hours to see if you should buy the plants.
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