Certified GKH Gardening Expert
Here's some info from the article on our website:
"Harvesting pistachio trees is easy because Mother Nature does most of the work. Just spread a large tarp under the tree so the ripe nuts aren’t harmed by falling in the dirt. Pistachio orchardists use mechanical “shakers” to loosen the nuts, but you can dislodge them by rapping the branches with a sturdy pole or a rubber mallet. At this point, pistachio harvesting is simply a matter of gathering the dropped nuts. To maintain flavor and quality, remove the epicarp within 24 hours of harvest."
You can read the entire article here: https://www.gardeningknowhow.com/edible/nut-trees/pistachios/how-to-harvest-pistachios.htm
If you need more in-depth detail, we recommend talking with your local cooperative extension service.