Our surveys indicate that native bees may outnumber honey bees in many orchards and we are trying to determine what orchard management practices promote native bee abundance and diversity. Many local apple growers no longer bring honey bees into their orchards - they are relying increasingly on the naturally occurring native bees for apple pollination.Holy Cow! Farmers that don't use honey bees for pollination. It really is the future, and of course this supports my saying that honey bee hives should be viewed more as a crop, especially for the backyard beekeeper. They're still useful as pollinators for some crops. And where native bees aren't abundant they can easily be used for quick pollination services. One thing I've found that's needed to build a good native bee population is a healthy environment. Usually this would be the hedge, or forested water shed area surrounding the farm. Mainly an abundance of soil types, slopes, hallow stemmed plants, dead wood, with an abundance of native plants that flower when the bees are active are needed for these other pollinators to show up and establish themselves. This can be tricky though for farmers because they want the bees to focus on their crop most of all. Maintaining a patch of wildflowers and mowing it over when the crop starts blooming would solve this problem.
Knox Cellars. There are other providers on the web of course and a number of systems available on Amazon too.
Search Amazon.com for mason bee
I haven't tried them all of course but I can say this one here didn't work for me. It's made by an Asian company that uses bamboo sticks as tubes. It's likely intended to attract the Giant Resin Bee, Megachile sculpturalis, another import from Asia. Like the smaller mason bee they use tubes, usually the former nests to the Giant Carpenter Bees that they resemble.