They’re on the Same Line of Latitude as the South of France
Gorillas can eat leaves all year round because they live in the tropics. What about those of us who live in the North? The only leaves I see around here today are pine needles, which don’t seem edible.
We could eat produce that has been shipped from Florida or California, but think of all the fossil fuel that would get burned up. Is there another alternative? Evidently, there is. Eliot Coleman has written books about how to grow tasty leaves all year round, in an unheated greenhouse, in Maine. After he realized the shocking fact that his home in Maine is on the same line of latitude as the South of France, he started using the same techniques that the Europeans have long used for extending their growing season. He now harvests salad greens all year round.
http://www.fourseasonfarm.com/books/index.html#harvest
For the really hard-core, here’s a greenhouse from Canada that works without supplemental heat in temperatures of -30 degrees Fahrenheit. It’s insulated with soap bubbles.