Canning and drying are the two best methods of preserving food in a SHTF situation. A root celler is good also for potatoes, carrots, any root crop, and apples. My grandmother canned on a wood stove with a pressure cooker. Just had to watch it constantly and move it sometimes to a cooler spot. They did use coal sometimes also, for a more consistant burn. She canned a lot of fruits and jellies when they were in season. Also made wine. She used wild plumbs, muskedines, strawberries, and blackberries. They also had a fig tree, and two pear trees that always over produced. They had an apple and peach tree, but they weren't as productive. They had pecans and walnuts also. They grew a lot of different veggies and chickens.