> the total U.S. crop value that was wholly dependent on honey bee pollination was estimated to exceed $15 billion.
and
> honeybees perform some level of pollination of nearly 75% of all plant species directly used for human food worldwide.
Which sounds like a bit more than just beekeeping.
[1] https://en.wikipedia.org/wiki/Colony_collapse_disorder#Econo...
Bees pollinate 75% of species, but not 75% of calories. The major cereals (wheat, corn, rice) are all self or wind pollinating, as are number of other staples (e.g. potatoes, peas).
It's also worth remembering that if your concern over bees is environmental and not economic, honey bees compete with native bees and also transmit pathogens to them. They're not entirely benign.
Besides, aren't solitary bees supposed to be better pollinators?
As much as I like honey, I can't help but thinking there is a huge gap in logic with all of these people waving and screaming we aren't going to have food because of dwindling honey bee populations.
So any plant that's say native to the new world (corn, beans, squash, tomatoes) must not rely on honeybees for pollination.
This is not to say that there's not a bee problem: non-honey bees suffer from habitat loss (and a lack of investment keeping them around).
Some families of plants native of Europe use bees, other not. Is more about plant phylogeny than about geography. Similar species of flowers in other areas are quickly adopted by bees when available.
Obviously, worth noting that the trees you're listing --- with the possible exception of plums --- are also non-native. Which doesn't make them bad, but does make this an industrial agriculture problem, not an environmental one. And industrial agriculture seems to have the honey bee maintenance problem basically under control.
Osmia lignaria is US native and used to pollinate almonds and orchards, but is not so common.
There are other mason bees native from USA like Osmia ribifloris but they pollinate manzanitas (a relative to Rhododendron), not manzanas (apples). They can pollinate blueberries also (that are in the same family as Manzanitas and share similarly shaped flowers).