Perhaps an odd suggestion, but plant more fruit trees.
I do not suggest you start your own big commercial scale orchard, I do not even suggest you plant on your own land.
Naturally it is good to have your own tree if you have room on your property, but my suggestion is actually to use available space, even if that particular property belongs to someone else.
What am I talking about?
Well it is easy.
In the event of a major catastrophic event, the survivors (and hopefully you are one of them) will have the small issue of obtaining food. If deathtolls are high from for example a plague, there may be a lot of canned food in stores, but eventually that will run out.
My suggestion, to prepare the land for survival, is to make sure that there will at least be fruits available in the autumn. When you eat an apple, do not put the core in the garbage, instead dig a small hole and bury it somewhere where an appletree would have space to grow. It could be anywhere, in a park, beside a road, between roads, anywhere where there is soil or a lawn.
If someone tends that lawn, the tree will be cut down by the lawnmover. Thats allright, that means things are still normal. But should a plague strike, the chanses are that the one normally cutting the lawns in the park will be dead, or to busy with survival to spend time on that. And the trees will grow.
You do no harm by burrying a seed, but if the worst happens you have increased the chanses for the survivors. Especially if you choose fruits that you can store, perhaps dried. It usually takes at least 4 years before a tree begins to give fruite, so if you can give it one or two years headstart, it is more lilely that there will be fruits available when the canned goods run out.
I have a plum tree in the yard, so have several of my neighbours. But what they do not know is that in the cemetery 10 minutes away, there are not only the ashes and remains of people burried. Along the paths beside the graves I have planted more than 200 stones from plums. As the lawns there are well kept and the grass cut short every week, those will not become trees unless something happens. But if something do happen, the restingplace of the dead might be what saves the life of people nearby.
Every autumn I'll replant those plums, and hope that they will never need to grow.
Farmers only worry during the growing season, but towns people worry all the time.
-- Edgar Watson Howe